WO2024090449A1 - Metal additive manufacturing (am) copper alloy powder and method for producing addivtively manufactured article - Google Patents

Metal additive manufacturing (am) copper alloy powder and method for producing addivtively manufactured article Download PDF

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WO2024090449A1
WO2024090449A1 PCT/JP2023/038396 JP2023038396W WO2024090449A1 WO 2024090449 A1 WO2024090449 A1 WO 2024090449A1 JP 2023038396 W JP2023038396 W JP 2023038396W WO 2024090449 A1 WO2024090449 A1 WO 2024090449A1
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copper alloy
metal
alloy powder
powder
copper
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PCT/JP2023/038396
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French (fr)
Japanese (ja)
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晋吾 平野
清之 大久保
訓 熊谷
純 加藤
裕明 池田
和久 峰
伸康 二田
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三菱マテリアル株式会社
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  • the present invention relates to a copper alloy powder for metal additive manufacturing (metal AM) that is optimal for metal AM technology, and a method for manufacturing an additively manufactured object.
  • metal AM metal additive manufacturing
  • metal AM technology which uses powder as the main raw material and creates products using a metal 3D printer, has been put to practical use as a method for manufacturing metal parts with various three-dimensional shapes.
  • Major metal AM technologies using metal powder include powder bed fusion (PBF) using electron beams or laser light, and binder jetting.
  • Copper alloys have many basic properties suitable for industrial applications, such as electrical conductivity, thermal conductivity, mechanical properties, wear resistance, and heat resistance, and are used as materials for various components.
  • attempts have been made to form components of various shapes by metal AM using copper alloy powder in various fields such as space and electrical component applications, and there is an increasing need for copper and copper alloy components manufactured by metal AM.
  • Patent Document 1 proposes a technique for producing an additive manufacturing object by metal AM using a copper alloy powder containing either Cr or Si.
  • Patent Document 2 proposes a technique for producing an additive manufacturing object by metal AM using a copper alloy powder containing Cr and Zr.
  • Metal structures created by metal AM will be used as structural components for a variety of applications; therefore, if voids are present in the additively created body or if the microstructure of the metal material is uneven, this can cause problems in terms of thermomechanical and electrical reliability.
  • the most commonly used manufacturing method for metal AM is laser PBF, and attempts are being made to use laser PBF for manufacturing copper and copper alloys as well.
  • a thin layer of powder is first formed (powder bed), and then the powder bed is locally irradiated with a laser or an electron beam to melt and solidify the material.
  • copper and copper alloys compared with other metal materials such as iron, titanium, and nickel, copper itself has a high reflectance in the visible and infrared ranges, which causes the melting behavior of the copper alloy powder to become unstable during the laser PBF process, and voids are likely to occur inside the manufactured additive manufacturing product, resulting in a number of problems such as unstable quality of the product manufactured by laser PBF and poor productivity, and there is a demand for improvements in the productivity and quality of copper and copper alloys manufactured by laser PBF.
  • the most widely used form of raw material for metal AM is powder.
  • the electromagnetic wave absorption characteristics of the particles due to coupling and interaction with the electromagnetic waves of the surface layer of each particle constituting the raw material powder affect the melting behavior of the raw material powder, and greatly affect the productivity of parts and the quality including the defect density of the parts.
  • the thickness of the powder bed formed in one stacking process is, for example, about several tens of ⁇ m (Non-Patent Document 1), and the raw material powder is melted by irradiating such a relatively thin powder bed with converged electromagnetic waves, and the desired modeling structure is realized by repeating numerous stacking and melting and solidification.
  • the electromagnetic wave absorption characteristics of solids have a significant impact on the elementary process of such additive manufacturing using a powder bed. For example, since the electromagnetic wave absorption characteristics of solids are affected by the material composition, improving the uniformity of the powder material composition and microstructure is extremely important for achieving stable quality and high productivity in the entire additive manufacturing product.
  • the electromagnetic wave absorption characteristics of copper and copper alloys can be improved, for example, by simply adding a substance with a high absorption rate of the target laser wavelength as a component other than copper.
  • the characteristics required for that application can only be realized by appropriately selecting the type and amount of elements added to copper. Therefore, in order to improve the productivity and quality of metal AM objects made of copper or copper alloys, in other words, to improve the laser absorption of raw powders of copper or copper alloys, a simple approach such as adding various foreign elements with high laser absorption rates to copper or copper alloys of optimized composition or increasing the amount of such elements added may deteriorate the performance of copper alloys required for various applications. Therefore, there has been a demand for realizing copper alloy powders for metal AM with improved laser absorption characteristics while maintaining a material composition that can fully ensure the performance of copper alloys required for various applications.
  • One important approach to improving the laser absorption properties of powder is to improve the laser absorption ability of each particle by surface modification of each particle that constitutes the powder.
  • this surface modification it is possible to apply a coating of a substance that exhibits high absorption rate for the laser wavelength used in metal AM to the surface of each particle of the powder having the desired copper alloy composition.
  • a desired coating material may be formed on the particle surface using a wet or gas phase process.
  • such a coating process is plagued with problems not only in controlling the thickness of the coating layer on each particle, but also in reproducibility of the coating thickness and homogeneity of the coating material throughout the powder, resulting in a number of issues in the productivity and quality of the molded object.
  • one of the factors that can cause structural defects in metal AM objects is the generation of voids due to the entrapment of gases, etc.
  • gas is generated due to impurities contained in the copper alloy powder when the powder is melted, and the molten copper alloy or solidified copper alloy can trap the gas components, resulting in the generation of voids inside the additive object produced, which can make it difficult to consistently produce high-quality additive objects.
  • the reproducibility of the microstructure of such raw material powders is a similar problem with other metal AM methods such as the binder jet method.
  • metal AM of copper alloys improving productivity is a major challenge due to issues with the various raw materials.
  • This invention was made in consideration of the above-mentioned circumstances, and aims to provide a copper alloy powder for metal AM that can stably produce high-quality additively molded objects with high reproducibility of the microstructure of objects produced by metal AM and few structural defects such as voids, and a method for producing additively molded objects.
  • the copper alloy powder is derived from high-purity copper alloy raw materials, which means that there are fewer impurities that lead to gas components, suppressing the generation of gas during melting. This allows for the realization of dense copper alloy molded bodies with high thermal, electrical, and mechanical properties, and furthermore, it has been discovered that it is possible to manufacture copper alloy powder for metal AM that can achieve high productivity and high quality of copper alloy molded bodies that exhibit such high performance.
  • the copper alloy powder for metal AM of aspect 1 of the present invention is a copper alloy powder for metal AM used in metal AM, which is made of a copper alloy containing Si, and is characterized in that a Si-enriched layer is continuously formed on the surface of the copper alloy particles that make up the powder.
  • the copper alloy powder for metal AM according to aspect 1 of the present invention is made of a copper alloy containing Si, and a Si-enriched layer is continuously formed on the surface of the copper alloy particles that make up the powder. This makes it possible to stably manufacture high-quality additive manufacturing objects with high reproducibility of the microstructure of the objects produced by metal AM and with few structural defects such as voids.
  • the copper alloy powder for metal AM in the copper alloy powder for metal AM according to the first aspect, preferably contains Cr.
  • the copper alloy powder for metal AM of aspect 2 of the present invention which is made of a copper alloy containing Cr and Si, and has a Si-enriched layer continuously formed on the surface of the copper alloy particles, it is possible to stably produce high-quality additively molded objects with high reproducibility of the microstructure of the objects produced by metal AM and with few structural defects such as voids.
  • the Si-enriched layer preferably contains oxygen.
  • the Si-enriched layer formed on the surface of the copper alloy particles contains oxygen, deterioration of the copper alloy powder for metal AM can be suppressed, and the microstructure of the shaped body produced by metal AM can be highly reproducible, making it possible to more stably produce high-quality additively shaped objects with fewer structural defects such as voids.
  • the copper alloy in the copper alloy powder for metal AM according to any one of the first to third aspects, preferably contains Cr in the range of 0.1 mass % to 0.8 mass %, Si in the range of 0.4 mass % to 0.8 mass %, Ni in the range of 1.8 mass % to 3.0 mass %, and the remainder is copper and impurities.
  • the copper alloy powder for metal AM of aspect 4 of the present invention the copper alloy constituting the copper alloy powder for metal AM has the above-mentioned composition. Therefore, by subjecting an additive manufacturing object produced using this copper alloy powder for metal AM to an appropriate heat treatment, compounds can be precipitated, making it possible to produce an additive manufacturing object having excellent electrical conductivity, thermal conductivity, and strength.
  • the volume-based 50% cumulative particle diameter D50 measured by a laser diffraction/scattering method is in the range of 5 ⁇ m or more and 120 ⁇ m or less.
  • the 50% cumulative particle diameter D50 on a volume basis measured by a laser diffraction/scattering method is within the range of 5 ⁇ m or more and 120 ⁇ m or less, so that the powder has a particle size distribution suitable for metal AM and enables stable production of additive manufacturing objects.
  • a 10% cumulative particle diameter D10 on a volume basis measured by a laser diffraction/scattering method is in the range of 1 ⁇ m or more and 80 ⁇ m or less.
  • the volume-based 10% cumulative particle diameter D10 measured by a laser diffraction/scattering method is in the range of 1 ⁇ m or more and 80 ⁇ m or less, so that it has a particle size distribution suitable for metal AM and enables the stable production of additive manufacturing objects.
  • the volume-based 90% cumulative particle diameter D90 measured by a laser diffraction/scattering method is in the range of 10 ⁇ m or more and 150 ⁇ m or less.
  • the volume-based 90% cumulative particle diameter D90 measured by a laser diffraction/scattering method is in the range of 10 ⁇ m or more and 150 ⁇ m or less, so that it has a particle size distribution suitable for metal AM and enables the stable production of additive manufacturing objects.
  • the method for manufacturing an additively molded object according to aspect 8 of the present invention preferably comprises a preparation step of preparing a copper alloy powder for metal AM according to any one of aspects 1 to 7, a first step of forming a powder bed containing the copper alloy powder for metal AM, and a second step of solidifying the copper alloy powder for metal AM at a predetermined position in the powder bed to form a molding bed, and a molding step of producing an additively molded object by sequentially repeating the steps.
  • the method for manufacturing an additively molded product according to aspect 8 of the present invention uses a copper alloy powder for metal AM according to any one of aspects 1 to 7, which makes it possible to stably manufacture high-quality additively molded products with high reproducibility of the microstructure of the object produced by additive manufacturing and few structural defects such as voids.
  • the method for manufacturing an additively molded object of aspect 9 of the present invention is preferably the method for manufacturing an additively molded object of aspect 8, further comprising a heat treatment step of performing heat treatment at a temperature range of 300°C or higher and lower than the melting point of pure copper after the molding step.
  • a heat treatment step of performing heat treatment at a temperature range of 300°C or higher and lower than the melting point of pure copper after the molding step.
  • the manufacturing method of an additively molded object of aspect 10 of the present invention is preferably the same as the manufacturing method of an additively molded object of aspect 8, further comprising a first heat treatment step in which heat treatment is performed in a temperature range of 800°C or higher and lower than the melting point of pure copper after the molding step, and a second heat treatment step in which heat treatment is performed in a temperature range of 300°C or higher and lower than 800°C after the first heat treatment.
  • the present invention provides a copper alloy powder for metal AM that can stably produce high-quality additively molded objects with high reproducibility of the microstructure of objects produced by metal AM and few structural defects such as voids, and a method for producing additively molded objects.
  • FIG. 1 is a schematic explanatory diagram of a copper alloy particle constituting a copper alloy powder for metal AM according to an embodiment.
  • FIG. 1 is a flow diagram of a method for producing a copper alloy powder for metal AM according to the present embodiment.
  • FIG. 1 is a schematic explanatory diagram of a continuous casting device used when producing the copper alloy powder for metal AM according to the present embodiment.
  • FIG. 2 is a flow diagram of a method for producing a layered object according to the present embodiment.
  • FIG. 2 is a schematic explanatory diagram of another continuous casting device used in producing the copper alloy powder for metal AM according to the present embodiment.
  • FIG. 1 is a diagram showing the results of Auger electron spectroscopy analysis of the outermost surface of a particle constituting the copper alloy powder for metal AM according to the present embodiment, and is a secondary electron image of the particle surface.
  • FIG. 2 is a diagram showing the results of Auger electron spectroscopy analysis of the outermost surface of a particle constituting the copper alloy powder for metal AM according to the present embodiment, and is an element mapping image of the particle surface.
  • 1 is an example of a graph showing the results of Auger electron spectroscopy analysis of the outermost surface of a particle constituting the copper alloy powder for metal AM according to the present embodiment, and shows an O intensity depth profile.
  • 1 is an example of a graph showing the results of Auger electron spectroscopy analysis of the outermost surface of a particle constituting the copper alloy powder for metal AM according to this embodiment, and shows an intensity depth profile of Si.
  • the copper alloy powder for metal AM according to the present embodiment is a copper alloy powder used for metal AM. Note that the copper alloy powder for metal AM according to the present embodiment is considered to be particularly suitable for the laser PBF method.
  • the copper alloy powder for metal AM of this embodiment is an aggregate of particles made of a copper alloy containing Si, and a Si-concentrated layer is continuously formed on the surface of the copper alloy particles that make up the copper alloy powder for metal AM. That is, as shown in FIG. 1, the copper alloy particle 50 of the copper alloy powder for metal AM of this embodiment has a particle body (copper alloy particle) 51 made of a copper alloy containing Si, and a Si-concentrated layer 52 formed on the surface (or surface layer) of this particle body 51.
  • the surface (particle surface) (or surface layer) of the copper alloy particle of the copper alloy powder for metal AM is a region from the outermost surface of the particle to a depth of 100 nm.
  • the Si-enriched layer 52 is a layer in which a portion having a Si intensity amplification factor (defined below) of 2 or more is analyzed from the results of Auger electron spectroscopy on the surface of the particle body 51. This analysis method will be described below. Using a scanning Auger electron spectrometer PHI700xi manufactured by ULVAC-PHI, Inc., the signal intensity of Si element (IAES(t)) over measurement time (t) is measured every 30 seconds from the start of Auger electron signal measurement on the surface of the particle body 51 to be analyzed.
  • a Si intensity amplification factor defined below
  • the Si-enriched layer 52 is identified by Auger electron spectroscopy as follows.
  • the signal intensity (I AES (t)) of the Si element is measured over the measurement time (t) every 30 seconds from the start of Auger electron signal measurement on the particle surface to be analyzed.
  • Six or more regions where the I AES (t) for the Si element is roughly constant are then identified, and the average value of I AES (t) is calculated in these regions where the I AES (t) is constant. This average value is defined as the average background intensity (I AES , BG AVE ).
  • the I AES (t) at all the acquired times t is divided by the I AES , BG AVE to obtain a numerical value.
  • This numerical value is defined as I AES, NORM (t).
  • I AES, NORM (t) is expressed by the following formula (1).
  • I AES, NORM (t) I AES (t) / I AES , BG AVE Equation (1)
  • I AES,NORM (t) increases continuously with decreasing measurement time in the Si-enriched layer 52.
  • the start time of the region where this continuous increase in I AES,NORM (t) is observed is defined as the time t s0 which marks the end of the Si-enriched layer.
  • ts0 is approximately 2 min.
  • I AES,NORM (t) calculated by formula (1) is called the Si intensity amplification factor. According to Table 5, in an embodiment in which the Si-enriched layer 52 is present, a value of the Si intensity amplification factor exceeding 2 is clearly observed, and a situation in which the Si signal intensity is clearly stronger than the background intensity is confirmed.
  • a Si-enriched layer 52 is present on the surface of the particle body 51.
  • a portion of the Si-enriched layer 52 may have a Si intensity magnification factor of less than 2 to 1.7, for example.
  • the Si-enriched layer 52 formed on the surface of the particle body 51 of the copper alloy particle 50 of the copper alloy powder for metal AM contains oxygen (O).
  • the thickness of the Si-enriched layer 52 formed on the surface of the particle body 51 is preferably 1 nm or more and 100 nm or less.
  • the thickness of the Si-enriched layer 52 is preferably 1 nm or more, and may be 5 nm or more, 10 nm or more, 20 nm or more, 30 nm or more, or 50 nm or more.
  • the thickness of the Cr compound layer 52 is preferably 100 nm or less, and may be 95 nm or less, 90 nm or less, 80 nm or less, or 70 nm or less.
  • the thickness of the Si-enriched layer 52 is determined by etching the surface of the copper alloy particles 50 of the copper alloy powder for metal AM by ion etching at an etching rate of 1.08 nm/min under the standard etching conditions, and analyzing the surface of the copper alloy particles 50 of the copper alloy powder for metal AM by Auger electron spectroscopy using a scanning Auger electron spectrometer PHI700xi manufactured by ULVAC-PHI, Inc. to obtain a Si mapping image showing the Si compound, and obtaining a silicon (Si) intensity depth profile (a graph showing the relationship between intensity and etching time shown in FIG. 7B).
  • the copper alloy constituting the copper alloy particles 50 of the copper alloy powder for metal AM of this embodiment preferably contains Cr as an alloying element. This is because the addition of Cr to the copper alloy produces compounds of Cr and Si in the copper alloy, and in particular the compounds of Cr and Si present on the surface of the copper alloy particles contribute to improving the laser absorption rate.
  • the copper alloy constituting the copper alloy particles 50 of the copper alloy powder for metal AM of this embodiment preferably contains Ni as an alloying element. This is because the addition of Ni to the copper alloy causes Ni to dissolve in the Cu crystal grains, which contributes to improving the laser absorptivity of the Cu crystal grains in the copper alloy particles.
  • the content of Ni contained as an alloying element is preferably 3.0 mass% or less.
  • the copper alloy constituting the copper alloy particles 50 of the copper alloy powder for metal AM of this embodiment preferably contains, as alloy elements, Cr in the range of 0.1 mass% to 0.8 mass%, Si in the range of 0.4 mass% to 0.8 mass%, Ni in the range of 1.8 mass% to 3.0 mass%, and the rest is composed of copper and impurities. That is, the copper alloy constituting the copper alloy particles 50 of the copper alloy powder for metal AM of this embodiment preferably has a composition equivalent to C18000.
  • the alloy elements refer to Cr, Si, and Ni.
  • the impurities referred to here are components including impurity elements described below as well as O, H, S, and N.
  • the numerical accuracy error is ⁇ 10% (excluding O, H, S, and N).
  • the lower limit of the Cr content is more preferably 0.2 mass% or more, and even more preferably 0.3 mass% or more.
  • the upper limit of the Cr content is more preferably 0.8 mass% or less, and even more preferably 0.7 mass% or less.
  • the lower limit of the Si content is more preferably 0.45 mass% or more, and even more preferably 0.5 mass% or more.
  • the upper limit of the Si content is more preferably 0.7 mass% or less, and even more preferably 0.6 mass% or less.
  • the lower limit of the Ni content is more preferably 1.9 mass% or more, and even more preferably 2.0 mass% or more.
  • the upper limit of the Ni content is more preferably 2.9 mass% or less, and even more preferably 2.8 mass% or less.
  • the copper alloy constituting the copper alloy particles 50 of the copper alloy powder for metal AM may contain additive elements and impurity elements (excluding O, H, S, and N) other than the alloy elements.
  • the additive elements are elements that are intentionally added to the copper alloy particles 50 of the copper alloy powder for metal AM of this embodiment.
  • the impurity elements (excluding O, H, S, and N) are elements that are unintentionally mixed into the copper alloy particles 50 of the copper alloy powder for metal AM of this embodiment, and originate from contamination during the manufacturing process or impurities contained in trace amounts in the raw materials.
  • the impurity elements may be unavoidable impurities.
  • additive elements and impurity elements (excluding O, H, S, and N) other than the alloy elements constituting the copper alloy particles 50 of the copper alloy powder for metal AM include Zr, Mg, Ti, Al, Zn, Ca, Sn, Pb, Fe, Mn, Te, Nb, P, Co, Sb, Bi, Ag, Ta, W, and Mo.
  • the additive elements and impurity elements (excluding O, H, S, and N) other than the alloy elements may include at least one element selected from the group consisting of Zr, Mg, Ti, Al, Zn, Ca, Sn, Pb, Fe, Mn, Te, Nb, P, Co, Sb, Bi, and Ag, Ta, W, and Mo.
  • the total amount of additive elements and impurity elements (excluding O, H, S, and N) other than the alloy elements constituting the copper alloy particles 50 of the copper alloy powder for metal AM may be 0.07 mass% or less, 0.06 mass% or less, or 0.05 mass% or less, preferably 0.04 mass% or less, more preferably 0.03 mass% or less, even more preferably 0.02 mass% or less, and even more preferably 0.01 mass% or less.
  • the upper limit of the content of each of the additive elements and impurity elements (excluding O, H, S, and N) other than the alloy elements constituting the copper alloy particles 50 of the copper alloy powder for metal AM is preferably 30 ppm by mass or less, more preferably 20 ppm by mass or less, and even more preferably 15 ppm by mass or less.
  • the 50% cumulative particle diameter D50 on a volume basis measured by a laser diffraction/scattering method is in the range of 5 ⁇ m or more and 120 ⁇ m or less
  • the 10% cumulative particle diameter D10 is in the range of 1 ⁇ m or more and 80 ⁇ m or less
  • the 90% cumulative particle diameter D90 is in the range of 10 ⁇ m or more and 150 ⁇ m or less.
  • the lower limit of the 50% cumulative particle size D50 is more preferably 10 ⁇ m or more, and even more preferably 15 ⁇ m or more.
  • the upper limit of the 50% cumulative particle size D50 is more preferably 100 ⁇ m or less, and even more preferably 90 ⁇ m or less.
  • the lower limit of the 10% cumulative particle size D10 is more preferably 5 ⁇ m or more, and even more preferably 10 ⁇ m or more.
  • the upper limit of the 10% cumulative particle size D10 is more preferably 70 ⁇ m or less, and even more preferably 60 ⁇ m or less.
  • the lower limit of the 90% cumulative particle size D90 is more preferably 20 ⁇ m or more, and even more preferably 30 ⁇ m or more.
  • the upper limit of the 90% cumulative particle size D90 is more preferably 140 ⁇ m or less, and even more preferably 120 ⁇ m or less.
  • the manufacturing method of copper alloy powder for metal AM according to this embodiment includes a melting and casting step S01 for obtaining a copper alloy ingot, a copper alloy raw material preparation step S02 for processing the obtained copper alloy ingot into a wire rod to obtain a copper alloy raw material, and a powder processing step S03 for processing the copper alloy raw material into powder.
  • a copper alloy ingot having a predetermined composition is produced.
  • the melting and casting process S01 includes a melting step, an alloying element addition step, and a continuous casting step.
  • a copper alloy ingot 1 is produced using a continuous casting apparatus 10 shown in FIG.
  • This continuous casting apparatus 10 includes a melting furnace 11, a tundish 12 arranged downstream of the melting furnace 11, a connecting trough 13 connecting the melting furnace 11 and the tundish 12, an addition section 14 for adding alloy elements in the tundish 12, a continuous casting mold 15 arranged downstream of the tundish 12, and a pouring nozzle 16 for pouring molten copper alloy from the tundish 12 into the continuous casting mold 15.
  • the copper raw material is melted in a non-oxidizing atmosphere (an inert gas atmosphere or a reducing atmosphere) to obtain molten copper 3 (melting step).
  • the copper raw material melted in the melting furnace 11 is high-purity copper having a purity of 99.99 mass% or more (e.g., high-purity electrolytic copper or oxygen-free copper).
  • the copper raw material to be melted is high-purity copper of 4N grade (99.99 mass%) or more, more preferably high-purity copper of 5N grade (99.999 mass%) or more, and even more preferably high-purity copper of 6N (99.9999 mass%) or more.
  • the obtained molten copper 3 is preferably oxygen-free molten copper.
  • the obtained molten copper 3 is supplied to the tundish 12 while maintaining a non-oxidizing atmosphere (an inert gas atmosphere or a reducing atmosphere).
  • the connecting trough 13 is disposed between the melting furnace 11 and the tundish 12, and the molten copper 3 passes through the inside of the connecting trough 13 in a non-oxidizing atmosphere.
  • the molten copper 3 is held in a non-oxidizing atmosphere (an inert gas atmosphere or a reducing atmosphere).
  • the connecting trough 13, and the tundish 12 are in a non-oxidizing atmosphere (an inert gas atmosphere or a reducing atmosphere), the gas components (O, H) in the molten copper 3 are reduced.
  • alloy elements Cr, Si, Ni, etc.
  • additive elements may be appropriately added here.
  • alloying elements By adding alloying elements to the molten copper 3 in which the gas components (O, H) have been sufficiently reduced, the yield of the alloying elements added is good, so that the amount of the alloying elements used can be reduced, and the manufacturing cost of the copper alloy can be reduced.
  • alloying elements By adding alloying elements to the molten copper 3 flowing inside the tundish 12, the alloying elements can be uniformly dissolved, and a molten copper alloy having stable component values can be continuously produced.
  • the obtained molten copper alloy is poured into a continuous casting mold 15 through a pouring nozzle 16 to continuously produce a copper alloy ingot 1 (continuous casting process).
  • a copper alloy ingot having a circular cross section is produced.
  • the obtained copper alloy ingot 1 has an O concentration of 10 ppm by mass or less and an H concentration of 5 ppm by mass or less.
  • the S concentration is preferably 15 mass ppm or less.
  • the total content of impurity elements other than Cu and alloy elements is preferably 0.04 mass% or less.
  • the total concentration of O, H and S is preferably 20 mass ppm or less.
  • the copper alloy raw material preparation step S02 includes an extrusion step, a drawing step, and a cutting step.
  • a copper alloy ingot having a circular cross section is heated and processed by hot extrusion into a rod having a predetermined diameter (extrusion step).
  • the heating temperature during the hot extrusion process is preferably set within a range of 700° C. or more and 1000° C. or less.
  • the obtained rod is subjected to drawing to produce a wire of a specified diameter (drawing process).
  • drawing process There are no particular restrictions on the temperature of the drawing process, but it is preferable to carry out the process at a temperature between -200°C and 200°C, which results in cold or warm rolling, and room temperature is particularly preferable.
  • the resulting wire is then cut to a predetermined length to provide a copper alloy raw material (cutting step).
  • the obtained copper alloy raw material has an O concentration of 10 mass ppm or less and an H concentration of 5 mass ppm or less.
  • the S concentration in the obtained copper alloy raw material is preferably 15 mass ppm or less.
  • the total content of impurity elements (excluding O, H, and S) other than Cu and alloy elements in the obtained copper alloy raw material is preferably 0.04 mass% or less.
  • the copper alloy raw material obtained in the copper alloy raw material preparation step S02 is subjected to an atomization process to produce copper alloy powder for metal AM.
  • This powder processing step S03 includes a melting step, an atomizing step, and a classification step.
  • the melting step the copper alloy raw material is heated and melted to obtain a molten alloy.
  • the melting atmosphere is preferably a non-oxidizing atmosphere.
  • powder is obtained by, for example, gas atomization. That is, the molten alloy obtained in the melting process is sprayed with high-pressure gas to rapidly cool the droplets of the molten alloy, thereby producing powder having a spherical or similar shape.
  • Inert gases such as argon and nitrogen can be used as the gas used in the gas atomization process.
  • the obtained powder is classified to obtain a copper alloy powder having a predetermined particle size distribution.
  • the melting temperature of the copper alloy raw material in the gas atomization process (the melting temperature during the gas atomization process) is preferably equal to or higher than the melting point of copper and equal to or lower than 1500° C.
  • the melting temperature during the gas atomization process may be equal to or higher than 1085° C. and equal to or lower than 1500° C.
  • the copper alloy powder for metal AM according to the present embodiment is manufactured by the above-mentioned steps.
  • the O concentration is preferably 1000 mass ppm or less
  • the H concentration is preferably 5 mass ppm or less
  • the S concentration is preferably 10 mass ppm or less.
  • the O concentration may be about 2700 ppm by mass or less, preferably 1000 ppm by mass or less, and more preferably 900 ppm by mass or less.
  • the lower limit of the O concentration is not particularly limited, but may be a value that does not include 0 (or a value that exceeds 0).
  • the H concentration may be 90 mass ppm or less, may be 60 mass ppm or less, and is preferably 5 mass ppm or less.
  • the lower limit of the H concentration is not particularly limited, but may be a value that does not include 0 (or a value that exceeds 0).
  • the S concentration may be 90 mass ppm or less, may be 60 mass ppm or less, and is preferably 30 mass ppm or less.
  • the S concentration in the copper alloy powder for metal AM is more preferably 10 mass ppm or less.
  • the lower limit of the S concentration is not particularly limited, but may be a value that does not include 0 (or a value that exceeds 0).
  • atmospheric components contained in the atmosphere or during the process may cause the powder to contain atmospheric components.
  • nitrogen derived from atmospheric components may be contained in the powder.
  • the nitrogen concentration (N concentration) is preferably 30 mass ppm, more preferably 20 mass ppm, and even more preferably 10 mass ppm or less.
  • the nitrogen concentration (N concentration) is more preferably 5 mass ppm or less.
  • the lower limit of the N concentration is not particularly limited, but may be a value that does not include 0 (or a value that exceeds 0).
  • the copper alloy powder for metal AM may contain additive elements and impurity elements other than the alloy elements to the extent that they do not affect the characteristics.
  • the total amount of additive elements other than alloy elements and impurity elements may be 0.07 mass% or less, may be 0.06 mass% or less, may be 0.05 mass% or less, is preferably 0.04 mass% or less, is more preferably 0.03 mass% or less, is further preferably 0.02 mass% or less, and is further preferably 0.01 mass% or less.
  • the upper limit of the content of each of additive elements other than alloy elements and impurity elements is preferably 30 mass ppm or less, more preferably 20 mass ppm or less, and even more preferably 15 mass ppm or less.
  • the manufacturing method of an additively molded object in this embodiment includes a preparation process S101 for preparing the above-mentioned copper alloy powder for metal AM, a first process S121 for forming a powder layer containing the copper alloy powder for metal AM, and a second process S122 for solidifying the copper alloy powder for metal AM at a predetermined position in the powder layer to form a molding layer, and a modeling process S102 for producing an additively molded object by sequentially repeating these steps.
  • a layered object having a predetermined shape is manufactured. Since the layered object uses the copper alloy powder for metal AM according to the present embodiment, the layered object has few structural defects such as voids and has excellent mechanical properties.
  • the copper alloy powder for metal AM of this embodiment configured as described above is composed of copper alloy particles 50 containing Si, and Si is segregated on the surface of the copper alloy particles 50 that constitute the copper alloy powder for metal AM, and a Si-enriched layer 52 is formed on the outer surface of the particle body 51.
  • the Si-enriched layer 52 formed on the surface of the particle body 51 is an oxide layer containing Si and O, it is possible to suppress the deterioration of the copper alloy powder for metal AM, and it is possible to more stably manufacture an even higher quality additively manufactured object with high reproducibility of the microstructure of the object produced by additive manufacturing and with fewer structural defects such as voids.
  • the copper alloy powder for metal AM of this embodiment when the copper alloy constituting the copper alloy particles 50 contains Cr in the range of 0.1 mass% to 0.8 mass%, Si in the range of 0.4 mass% to 0.8 mass%, Ni in the range of 1.8 mass% to 3.0 mass%, and the rest is copper and impurities, by subjecting an additive manufacturing product made using this copper alloy powder for metal AM to an appropriate heat treatment, compounds can be precipitated, making it possible to manufacture an additive manufacturing product with excellent electrical conductivity, thermal conductivity, and strength.
  • the 50% cumulative particle diameter D50 on a volume basis measured by the laser diffraction/scattering method is within the range of 5 ⁇ m or more and 120 ⁇ m or less, it has a particle size distribution suitable for metal AM, and it becomes possible to stably manufacture additive manufacturing objects.
  • the volume-based 10% cumulative particle diameter D10 measured by the laser diffraction/scattering method is within the range of 1 ⁇ m or more and 80 ⁇ m or less, it has a particle size distribution suitable for metal AM, and it becomes possible to stably manufacture additive manufacturing objects.
  • the volume-based 90% cumulative particle diameter D90 measured by the laser diffraction/scattering method is within the range of 10 ⁇ m or more and 150 ⁇ m or less, it has a particle size distribution suitable for metal AM, and it becomes possible to stably manufacture additive manufacturing objects.
  • the manufacturing method for additive manufacturing of this embodiment uses the copper alloy powder for metal AM of this embodiment, which makes it possible to reproducibly produce the microstructure of the object produced by additive manufacturing, and to stably manufacture high-quality additive manufacturing objects with few structural defects such as voids.
  • the copper alloy powder for metal AM and the method for manufacturing an additive manufacturing object according to the embodiment of the present invention have been described above.
  • the present invention is not limited thereto and can be modified as appropriate without departing from the technical concept of the invention.
  • the copper alloy powder for metal AM is produced by gas atomization, but this is not limited thereto, and the copper alloy powder for metal AM may be produced by water atomization, centrifugal atomization, plasma atomization, or the like.
  • the copper alloy powder for metal AM obtained as described above may be appropriately heat-treated in a controlled atmosphere to stabilize the structure. Furthermore, in this embodiment, the copper alloy powder for metal AM suitable for the laser PBF method has been described as being produced, but this is not limited to this, and the copper alloy powder for metal AM applicable to other additive manufacturing methods may also be used.
  • a heat treatment process may be performed in which heat treatment is performed at a temperature of 300° C. or more and the melting point of pure copper or less.
  • a first heat treatment process may be performed in which heat treatment is performed at a temperature range of 800° C. or more and the melting point of pure copper or less, and after this first heat treatment process, a second heat treatment process may be performed in which heat treatment is performed at a temperature range of 300° C. or more and 800° C. or less.
  • the continuous casting apparatus shown in FIG. 3 is used to produce a copper alloy ingot, but the present invention is not limited to this, and other casting apparatuses may be used.
  • a continuous casting device 101 shown in FIG. 5 may be used.
  • This continuous casting device 101 includes an oxygen-free copper supply means (molten copper supply section) 102 arranged at the most upstream portion, a heating furnace 103 arranged downstream thereof, a tundish 104 arranged downstream of the heating furnace 103 and supplied with molten copper, molten metal supply passages 105a, 105b, and 105c connecting the oxygen-free supply means 102 to the heating furnace 103, a trough 106 connecting the heating furnace 103 and the tundish 104, addition means (addition sections) 107 and 108 for adding alloy elements in a non-oxidizing atmosphere, and a continuous casting mold 142.
  • the oxygen-free copper supply means 102, the heating furnace 103, the tundish 104, the molten metal supply passages 105a, 105b, and 105c, and the trough 106 each have a non-oxidizing atmosphere inside.
  • the oxygen-free copper supply means 102 is composed of a melting furnace 121 for melting the copper raw material, a holding furnace 122 for temporarily holding the molten copper obtained by melting in the melting furnace 121, a degassing treatment device 124 for removing oxygen and hydrogen from the molten copper, and molten metal supply paths 105a, 105b, and 105c that connect these.
  • the degassing treatment device 124 has a gas bubbling device as stirring means for stirring the molten copper therein, and removes oxygen and hydrogen from the molten copper by bubbling with an inert gas, for example.
  • the molten metal supply passages 105a, 105b, and 105c have a non-oxidizing atmosphere therein to prevent the molten copper and the oxygen-free copper molten metal from being oxidized.
  • the non-oxidizing atmosphere is formed by blowing a mixed gas of nitrogen and carbon monoxide or an inert gas such as argon into the molten metal supply passages.
  • a first adding means 107 disposed in the heating furnace 103 and a second adding means 108 disposed in the tundish 104 are provided.
  • the alloying elements are added to the oxygen-free copper molten metal stored in the heating furnace 103.
  • the oxygen-free copper molten metal stored in the storage section is heated by a high-frequency induction coil, and the melting of the added alloying elements is promoted.
  • the alloying elements are continuously or intermittently charged from the second adding means 108 provided in the tundish 104, the alloying elements are added to the molten oxygen-free copper flowing in the tundish 104.
  • the molten oxygen-free copper flowing in the tundish 104 is heated in the heating furnace 103 and has a high temperature, and also flows within the tundish 104, the dissolution of the added alloying elements is promoted.
  • Example of the invention First, by the manufacturing method described in the embodiment, a copper raw material made of 4N grade high purity copper was used to produce an ingot of C18000 having the composition shown in Table 1. Next, the produced C18000 ingot was used as a raw material to produce copper alloy powder for metal AM having the composition shown in Table 2 by gas atomization using argon gas, and the powder was classified to a particle size suitable for the powder bed of metal AM. The melting temperature during the gas atomization process was 1400°C.
  • the particle size distribution of the copper alloy powder for metal AM of the present invention was measured using MT3300EXII manufactured by Microtrac Co., Ltd., and the particle size distribution was as follows: 10% cumulative particle size on a volume basis was 15 ⁇ m, 50% cumulative particle size was 24 ⁇ m, and 90% cumulative particle size was 38 ⁇ m.
  • a Si-enriched layer was observed on the surface of the copper alloy particles, as described later.
  • a small piece of an additive manufacturing object was produced using a commercially available laser PBF device at an energy density of 13 J/ mm2 .
  • Comparative Example As a comparative example, a copper alloy powder for metal AM having the composition of C18000, which does not have a Si-enriched layer formed on the particle surface, unlike the examples of the present invention, was prepared.
  • particle size distribution measurement was performed using MT3300EXII manufactured by Microtrac, and the particle size distribution was as follows: 10% cumulative particle size on a volume basis was 16 ⁇ m, 50% cumulative particle size was 28 ⁇ m, and 90% cumulative particle size was 45 ⁇ m.
  • a scanning Auger electron spectrometer PHI700xi manufactured by ULVAC-PHI, Inc. was used to measure the signal intensity ( IAES (t)) of the Si element over the measurement time (t) for the particle body to be analyzed every 30 seconds from the start of measurement of the Auger electron signal on the surface. Then, for one of these I AES (t), six or more regions where the I AES (t) for the Si element was roughly constant were identified, and the average value of I AES (t) was calculated in these regions where the I AES (t) was constant.
  • I AES, BG AVE average background intensity
  • I AES, NORM (t) I AES (t) / I AES , BG AVE Equation (1)
  • I AES,NORM (t) increased continuously with decreasing measurement time in the Si-enriched layer.
  • the start time of the region where this continuous increase in I AES,NORM (t) was observed was defined as t s0 , which is the end of the Si-enriched layer.
  • t s0 was about 2 min
  • I AES, NORM (t) was taken as the Si intensity amplification factor.
  • the measurement time (t), signal intensity of Si element (I AES (t)), and Si intensity magnification factor I AES, NORM (t) of the copper alloy powder for metal AM of the present invention obtained by the above measurements and calculations are shown in Table 5.
  • the average background intensity (I AES , BG AVE ) of the present invention example was 2847.57.
  • Table 5 in the present invention examples in which a Si-enriched layer exists, a Si intensity magnification factor exceeding 2 was clearly observed, and it was confirmed that the Si signal intensity was clearly stronger than the background intensity. Therefore, it was confirmed that a Si-enriched layer exists in the particle body of the copper alloy powder for metal AM of the present invention example.
  • no Si strength magnification factor exceeding 2 was observed, and it was considered that no Si-enriched layer was present in the particle body of the copper alloy powder for metal AM.
  • composition of ingot and copper alloy powder for metal AM The O concentration in the ingots shown in Table 1, the copper alloy powders for metal AM of the present invention, and the copper alloy powders for metal AM of the comparative examples was determined by inert gas fusion-infrared absorption method, the H concentration by inert gas fusion-thermal conductivity method, and the S concentration by combustion-infrared absorption method.
  • concentrations of components other than these substances, except for copper were determined by a combination of X-ray fluorescence analysis, glow discharge mass spectrometry, and inductively coupled plasma mass spectrometry. The evaluation results are shown in Tables 1 and 2.
  • the density of the layered object was evaluated from the cross section of the layered object and the area occupied by voids observed in the cross section of the layered object. In this specification, this density is defined as the density of the object.
  • the density of the molded object was evaluated by first defining the cross-sectional area of the object to be measured (this is called the evaluation cross-sectional area; 3.4 mm square), and then checking for voids within this measurement cross-sectional area, and calculating the area occupied by voids in the evaluation cross-sectional area. The density of the molded object was then defined as (evaluation cross-sectional area - void-occupied area)/evaluation cross-sectional area. The evaluation results of the density of the molded object are shown in Table 3.
  • Figures 6A and 6B show the results of Auger electron spectroscopy analysis of the particle surface of the copper alloy powder for metal AM of the present invention. As shown in Figures 6A and 6B, it was confirmed that a Si-enriched layer exists on the surface (or surface layer) of the copper alloy particles of the copper alloy powder for metal AM of the present invention, and that the particle surface is entirely covered with the Si-enriched layer.
  • FIG. 7A and 7B show the intensity depth profiles of Si and O obtained by Auger electron spectroscopy of the particle surface of the copper alloy powder for metal AM of the present invention.
  • the etching rate of each element alone or compounds generated by each element on the particle surface of the copper alloy powder of the present invention example in the experimental system of this Auger electron spectroscopy is not clear, but since the etching rate of SiO2 in the experimental system of this Auger electron spectroscopy is 1.08 nm/min, it is considered that the structure after ion etching for 7 minutes is approximately 10 nm thick.
  • the Si concentration is high on the surface side of the powder, and it was confirmed that a Si-enriched layer was formed on the surface of the powder. From this result, it is considered that the thickness of the Si-enriched layer is generally in the range of about 1 nm to 100 nm.
  • Si does not segregate on the surface of the powder, and it is recognized that a Si-enriched layer is not formed on the surface of the powder.
  • the O concentration on the surface side of the copper alloy powder for metal AM of the present invention is high, and the Si-enriched layer formed on the surface of the powder contains oxygen (O). That is, it is considered that the Si-enriched layer in the copper alloy powder for metal AM of the present invention is composed of a layer containing Si and O. Thus, it is considered that oxygen is also detected at the same time in the Si-enriched layer in the copper alloy powder for metal AM of the present invention, and surface deterioration of the copper alloy powder can be relatively suppressed.
  • the copper alloy powder for metal AM of the present invention contains oxygen as a copper alloy, so that a certain amount of oxygen exists in the particle body, which is considered to constitute the background concentration of oxygen in the particle body.
  • a gradient of oxygen concentration can be generated on the particle surface, mainly due to the powdering process, on the order of the thickness of the above-mentioned Si-enriched layer.

Abstract

This metal AM copper alloy powder for use in metal additive manufacturing (AM) comprises a copper alloy containing Si. An Si-enriched layer is continuously formed on the surface of copper alloy particles of which the powder is composed.

Description

金属ＡＭ銅合金粉末および積層造形物の製造方法Metal AM copper alloy powder and method for manufacturing laminated objects
　本発明は、金属アディティブ・マニュファクチャリング（金属ＡＭ）技術に最適な金属ＡＭ用銅合金粉末、および、積層造形物の製造方法に関する。
　本願は、２０２２年１０月２４日に、日本に出願された特願２０２２－１６９９２１号に基づき優先権を主張し、その内容をここに援用する。 The present invention relates to a copper alloy powder for metal additive manufacturing (metal AM) that is optimal for metal AM technology, and a method for manufacturing an additively manufactured object.
This application claims priority based on Japanese Patent Application No. 2022-169921, filed on October 24, 2022, the contents of which are incorporated herein by reference.
　近年、様々な立体形状を有する金属部品を製造する手法として、主に原料として粉を用いて金属３Ｄプリンターで製品を造形する金属ＡＭ技術が実用化されている。金属粉末を用いた主な金属ＡＭ技術としては、電子ビームやレーザー光を用いた粉末床溶融法（パウダー・ベッド・フュージョン：ＰＢＦ）、バインダジェット法等が挙げられる。
　ここで、銅合金は、導電性、熱伝導性、機械的特性、耐摩耗性、耐熱性など工業的な応用に適した多数の基本的性質を有しており、各種部材の素材として利用されている。そこで、近年、宇宙、電気部品応用など様々な分野において、銅合金粉末を用いた金属ＡＭにより、様々な形状の部材を形成することが試行され、金属ＡＭで製造された銅及び銅合金の部品のニーズが高まっている。 In recent years, metal AM technology, which uses powder as the main raw material and creates products using a metal 3D printer, has been put to practical use as a method for manufacturing metal parts with various three-dimensional shapes. Major metal AM technologies using metal powder include powder bed fusion (PBF) using electron beams or laser light, and binder jetting.
Copper alloys have many basic properties suitable for industrial applications, such as electrical conductivity, thermal conductivity, mechanical properties, wear resistance, and heat resistance, and are used as materials for various components. In recent years, attempts have been made to form components of various shapes by metal AM using copper alloy powder in various fields such as space and electrical component applications, and there is an increasing need for copper and copper alloy components manufactured by metal AM.
　例えば、特許文献１には、ＣｒとＳｉのいずれかを有する銅合金粉末を用いて、金属ＡＭによる積層造形物を作成する技術が提案されている。
　また、特許文献２には、ＣｒとＺｒを有する銅合金粉末を用いて、金属ＡＭによる積層造形物を作成する技術が提案されている。 For example, Patent Document 1 proposes a technique for producing an additive manufacturing object by metal AM using a copper alloy powder containing either Cr or Si.
Moreover, Patent Document 2 proposes a technique for producing an additive manufacturing object by metal AM using a copper alloy powder containing Cr and Zr.
特開２０１６－２１１０６２号公報JP 2016-211062 A 特開２０１９－０７０１６９号公報JP 2019-070169 A
　金属ＡＭにより造形される金属構造体は、様々な用途に応じて何らかの構造部材として用いられることになるため、積層造形体の中にボイドが存在する場合や金属材料としての微細構造が不均一である場合には、熱機械的また電気的な信頼性の点で問題となる。
　現在、金属ＡＭで最も多く使用されている造形方式はレーザーＰＢＦであり、銅及び銅合金においても、レーザーＰＢＦによる造形が試みられてきている。
　ところで、レーザー光や電子線を照射する方法で積層造形する際には、まず薄い粉末の層を形成し（粉末床）、続いてこの粉末床にレーザーや電子線を局所的に照射して材料を溶融凝固させる。しかし、銅及び銅合金においては、鉄、チタン、ニッケル系などの他の金属材料と比較して、銅そのものが可視、赤外域の光に対する反射率が高いことなどが原因となり、レーザーＰＢＦの過程で銅合金粉末の溶融挙動が不安定となり、作製された積層造形物の内部にボイドが発生しやすく、レーザーＰＢＦで製造した造形体の品質が安定しない、生産性が悪いなどの課題が山積しており、レーザーＰＢＦにより製造された銅及び銅合金の生産性及び品質の改善が求められてきている。 Metal structures created by metal AM will be used as structural components for a variety of applications; therefore, if voids are present in the additively created body or if the microstructure of the metal material is uneven, this can cause problems in terms of thermomechanical and electrical reliability.
Currently, the most commonly used manufacturing method for metal AM is laser PBF, and attempts are being made to use laser PBF for manufacturing copper and copper alloys as well.
Incidentally, when performing additive manufacturing using a method of irradiating a laser beam or an electron beam, a thin layer of powder is first formed (powder bed), and then the powder bed is locally irradiated with a laser or an electron beam to melt and solidify the material. However, in the case of copper and copper alloys, compared with other metal materials such as iron, titanium, and nickel, copper itself has a high reflectance in the visible and infrared ranges, which causes the melting behavior of the copper alloy powder to become unstable during the laser PBF process, and voids are likely to occur inside the manufactured additive manufacturing product, resulting in a number of problems such as unstable quality of the product manufactured by laser PBF and poor productivity, and there is a demand for improvements in the productivity and quality of copper and copper alloys manufactured by laser PBF.
　現在、最も広く使用されている金属ＡＭ用原料の形態は粉末である。例えば、レーザーＰＢＦを用いた金属ＡＭにおいては、原料粉末を構成する各粒子の表面層の電磁波とのカップリング・相互作用による粒子の電磁波の吸収特性が、原料粉末の溶融挙動に影響を及ぼし、部品の生産性や部品の欠陥密度を含む品質に大きく影響する。例えば、粉末床を用いる金属ＡＭプロセスにおいては、一回の積層過程で形成される粉末床の厚みは例えば数１０μｍ程度であり（非特許文献１）、収束した電磁波をこのような比較的薄い粉末床に照射することにより原料粉末を溶融させ、更に数多くの積層と溶融凝固を繰り返すことにより所望の造形構造を実現する。粉末床を用いるこのような積層造形の素過程に大きな影響を及ぼすのが固体の電磁波の吸収特性であり、例えば、固体の電磁波の吸収特性は材料組成により影響されるため、粉末の材料組成や微細構造の均一性を高めることは、積層造形物全体において安定した品質を実現することや高い生産性の実現において極めて重要となる。 Currently, the most widely used form of raw material for metal AM is powder. For example, in metal AM using laser PBF, the electromagnetic wave absorption characteristics of the particles due to coupling and interaction with the electromagnetic waves of the surface layer of each particle constituting the raw material powder affect the melting behavior of the raw material powder, and greatly affect the productivity of parts and the quality including the defect density of the parts. For example, in a metal AM process using a powder bed, the thickness of the powder bed formed in one stacking process is, for example, about several tens of μm (Non-Patent Document 1), and the raw material powder is melted by irradiating such a relatively thin powder bed with converged electromagnetic waves, and the desired modeling structure is realized by repeating numerous stacking and melting and solidification. The electromagnetic wave absorption characteristics of solids have a significant impact on the elementary process of such additive manufacturing using a powder bed. For example, since the electromagnetic wave absorption characteristics of solids are affected by the material composition, improving the uniformity of the powder material composition and microstructure is extremely important for achieving stable quality and high productivity in the entire additive manufacturing product.
　ここで、銅及び銅合金における電磁波の吸収特性は、例えば、単純に銅以外の成分として、目的のレーザー波長の吸収率が高い物質を添加することで改善可能である。しかしながら、過去の多くの冶金研究が示すように、銅及び銅合金をある応用に供する場合、その応用に必要な特性は、銅に添加される元素の種類とその添加量が適切に選択されることにより初めて実現される。従って、銅や銅合金の金属ＡＭ造形体の生産性や品質改善のために、言い換えると、銅や銅合金の原料粉末のレーザー吸収の改善のために、最適化された組成の銅や銅合金にレーザー吸収率の高い各種異元素を添加したり、その添加量を増加させたりするなどの単純なアプローチは、各種応用に必要な銅合金の性能を悪化させる可能性がある。従って、各種応用に必要な銅合金の性能を十分に確保することが可能な材料組成を維持しながら、レーザー吸収特性が改善された金属ＡＭ用銅合金粉末を実現することが求められてきた。 Here, the electromagnetic wave absorption characteristics of copper and copper alloys can be improved, for example, by simply adding a substance with a high absorption rate of the target laser wavelength as a component other than copper. However, as many past metallurgical studies have shown, when copper and copper alloys are used for a certain application, the characteristics required for that application can only be realized by appropriately selecting the type and amount of elements added to copper. Therefore, in order to improve the productivity and quality of metal AM objects made of copper or copper alloys, in other words, to improve the laser absorption of raw powders of copper or copper alloys, a simple approach such as adding various foreign elements with high laser absorption rates to copper or copper alloys of optimized composition or increasing the amount of such elements added may deteriorate the performance of copper alloys required for various applications. Therefore, there has been a demand for realizing copper alloy powders for metal AM with improved laser absorption characteristics while maintaining a material composition that can fully ensure the performance of copper alloys required for various applications.
　粉末のレーザー吸収特性の改善のための一つの重要なアプローチは、粉末を構成する各粒子表面の表面改質により各粒子のレーザー吸収能を改善することである。この表面改質のためには、所望の銅合金組成を有する粉末の各粒子の表面に、金属ＡＭで使用するレーザー波長に対し高い吸収率を示す物質のコーティングを施すことが考えられる。このような粒子表面のコーティングのアプローチとして、所望のコーティング材料を湿式や気相プロセスを用いて粒子表面に形成することがあり得る。しかしながら、このようなコーティングプロセスでは、各粒子でのコーティング層の厚みの制御だけではなく、粉末全体でのコーティング厚みやコーティング材料の均質性の再現性の問題が付きまとい、結果として造形体の生産性や品質において数々の課題が発生することになる。 One important approach to improving the laser absorption properties of powder is to improve the laser absorption ability of each particle by surface modification of each particle that constitutes the powder. For this surface modification, it is possible to apply a coating of a substance that exhibits high absorption rate for the laser wavelength used in metal AM to the surface of each particle of the powder having the desired copper alloy composition. As an approach to coating the particle surface, a desired coating material may be formed on the particle surface using a wet or gas phase process. However, such a coating process is plagued with problems not only in controlling the thickness of the coating layer on each particle, but also in reproducibility of the coating thickness and homogeneity of the coating material throughout the powder, resulting in a number of issues in the productivity and quality of the molded object.
　また、銅合金においては、過去の様々な研究開発の結果、高い導電性を維持しながら高い機械強度を実現した材料や、耐熱性に優れる材料などが既に開発されており、金属ＡＭにおいても、既存のこのような高性能銅合金材料を用いて所望の形状を有する金属ＡＭ部品を実現したい社会的要請がある。
　しかし、コーティングにより形成した特定成分の量を制御しながら、最終造形物の銅合金の材料組成を制御することは、大きな製造工程の負荷となるだけでなく、組成ばらつきや微細構造のばらつきに起因する造形部品の性能の悪化、部品の量産性の悪化、また部品の品質の維持の面など、多数の大きな問題を抱える懸念があった。 Furthermore, as a result of various past research and development efforts, copper alloy materials that achieve high mechanical strength while maintaining high electrical conductivity and materials with excellent heat resistance have already been developed, and in the field of metal AM, there is a social demand to realize metal AM parts having desired shapes using such existing high-performance copper alloy materials.
However, controlling the amount of specific components formed by the coating while also controlling the material composition of the copper alloy in the final product not only places a significant burden on the manufacturing process, but there were concerns that it could result in a number of major problems, such as deterioration of the performance of the molded parts due to variations in composition and microstructure, deterioration of mass producibility of parts, and issues with maintaining the quality of the parts.
　また、金属ＡＭ造形体の構造欠陥の原因となる一つの因子として、ガスなどの巻き込みに起因するボイドの発生がある。従来の銅合金粉末を用いてＰＢＦ法で積層造形した場合、粉末溶融時に、銅合金粉末に内包される不純物が原因となりガスが発生し、溶融した銅合金や凝固した銅合金がガス成分をトラップし、作製された積層造形物の内部にボイドが生じることがあり、安定して高品質な積層造形物を作製することができないおそれがあった。 Furthermore, one of the factors that can cause structural defects in metal AM objects is the generation of voids due to the entrapment of gases, etc. When conventional copper alloy powder is used for additive manufacturing using the PBF method, gas is generated due to impurities contained in the copper alloy powder when the powder is melted, and the molten copper alloy or solidified copper alloy can trap the gas components, resulting in the generation of voids inside the additive object produced, which can make it difficult to consistently produce high-quality additive objects.
　また、原料の粉末床にレーザー光や電子線を照射して積層造形する場合、レーザー光などが照射される各場所の粉末粒子の組成再現性を含む原料粉末に関わる微細構造の再現性が欠如している場合、粉末の溶融挙動が不均一となり、その結果、造形体内部にボイドなどの構造欠陥の発生を誘発したり、造形体の金属組成の不均一性による機械特性の悪化を生じさせたりするおそれがあった。 In addition, when additive manufacturing is performed by irradiating a powder bed of the raw material with laser light or electron beams, if there is a lack of reproducibility of the microstructure of the raw material powder, including the reproducibility of the powder particle composition at each location irradiated with the laser light, the melting behavior of the powder becomes non-uniform, which can result in the occurrence of structural defects such as voids inside the molded object, or the deterioration of mechanical properties due to non-uniformity in the metal composition of the molded object.
　また、このような原料粉末の微細構造の再現性は、粉末の材料組成の再現性を含み、バインダジェット法など他の金属ＡＭの工法においても同様な問題となっていた。銅合金の金属ＡＭにおいては、このような各種の原料の課題のため生産性の改善が大きな課題であった。 Furthermore, the reproducibility of the microstructure of such raw material powders, including the reproducibility of the powder's material composition, is a similar problem with other metal AM methods such as the binder jet method. In metal AM of copper alloys, improving productivity is a major challenge due to issues with the various raw materials.
　この発明は、前述した事情に鑑みてなされたものであって、金属ＡＭにより作製した造形体の微細構造の再現性が高く、ボイド等の構造欠陥が少ない高品質な積層造形物を安定して製造可能な金属ＡＭ用銅合金粉末、および、積層造形物の製造方法を提供することを目的とする。 This invention was made in consideration of the above-mentioned circumstances, and aims to provide a copper alloy powder for metal AM that can stably produce high-quality additively molded objects with high reproducibility of the microstructure of objects produced by metal AM and few structural defects such as voids, and a method for producing additively molded objects.
　この課題を解決するために、実応用に必要な銅合金組成を有しながらも、金属ＡＭプロセスを用いて高性能で高品質な銅合金部品を高い生産性で実現するための銅合金粉末を製造するための研究開発を行った。その結果、高純度の銅合金を原料として用いて粉末化処理を行った場合、銅合金粉末全体としては不純物が少なくかつ均一な組成を維持しながら、銅合金粉末中の個別の粒子表面に着目すると、レーザーが照射されることになる銅合金粒子表面に薄層が形成されていることが見いだされた。更に、この銅合金粒子表面に形成された薄層においては、バルクの銅合金粒子内部と比較し、銅よりも高いレーザー吸収を示す粉末構成元素が高頻度で存在するという特徴ある構造が、粉末への個別のコーティングプロセスや付加的なプロセスを経ることなく、銅合金原料からの直接的な粉末化プロセスにおいて自発的に生成することが見出された。 In order to solve this problem, we conducted research and development to manufacture copper alloy powder that has the copper alloy composition required for practical applications, but can also be used to produce high-performance, high-quality copper alloy parts with high productivity using a metal AM process. As a result, when a high-purity copper alloy is used as a raw material and powder processing is performed, it was found that while the copper alloy powder as a whole has few impurities and maintains a uniform composition, when focusing on the surfaces of individual particles in the copper alloy powder, a thin layer is formed on the copper alloy particle surface that is irradiated with a laser. Furthermore, it was found that in the thin layer formed on the copper alloy particle surface, compared to the interior of the bulk copper alloy particle, a characteristic structure in which powder constituent elements that exhibit higher laser absorption than copper are frequently present is spontaneously generated in the direct powder processing process from the copper alloy raw material, without going through an individual coating process or additional process on the powder.
　このような銅合金粒子表面の構造的特徴に加えて、高純度の銅合金原料に由来した銅合金粉末であることにより、ガス成分につながる不純物が少ないことで溶融時のガス発生を抑制することにより、高い熱的、電気的、機械的特性を有しながら、緻密な銅合金造形体を実現し、更にこのような高い性能を示す銅合金造形体の高い生産性と高い品質を実現することが可能な金属ＡＭ用銅合金粉末が製造できることを見出した。 In addition to these structural features of the copper alloy particle surface, the copper alloy powder is derived from high-purity copper alloy raw materials, which means that there are fewer impurities that lead to gas components, suppressing the generation of gas during melting. This allows for the realization of dense copper alloy molded bodies with high thermal, electrical, and mechanical properties, and furthermore, it has been discovered that it is possible to manufacture copper alloy powder for metal AM that can achieve high productivity and high quality of copper alloy molded bodies that exhibit such high performance.
　不純物が少ない銅原料に由来し、Ｓｉが添加された銅合金をアトマイズ処理することにより作製した銅合金粉末において、銅合金の溶湯を噴霧するアトマイズ工程における急速な微細化と温度変化に誘起される微細構造変化により、銅合金粉末を構成する粒子表面にＳｉ濃化層を自己形成的かつ連続的に形成させることに成功した。
　このような特徴的な表面構造を有する粒子から成る金属ＡＭ用銅合金粉末を用いて銅合金を積層造形した場合には、積層造形物中のボイドの発生を大幅に削減可能であり、緻密な銅合金の積層造形物を作製することが可能であるとの知見を得た。このような造形性に優れる銅合金粉末は従来の銅合金粉末よりも高い生産性を実現すると考えられる。 In copper alloy powder produced by atomizing copper alloys derived from copper raw materials with few impurities and containing added Si, the rapid micronization during the atomization process in which molten copper alloy is sprayed and the microstructural changes induced by temperature changes have succeeded in self-forming and continuous formation of a Si-enriched layer on the particle surfaces that make up the copper alloy powder.
It has been found that when copper alloy powder for metal AM made of particles having such a characteristic surface structure is used for additive manufacturing of copper alloy, it is possible to significantly reduce the occurrence of voids in the additive manufactured product, and it is possible to produce a dense additive manufactured product of copper alloy. It is believed that such copper alloy powder with excellent formability will achieve higher productivity than conventional copper alloy powders.
　本発明は、上述の知見に基づいてなされたものであって、本発明の態様１の金属ＡＭ用銅合金粉末は、金属ＡＭに用いられる金属ＡＭ用銅合金粉末であって、Ｓｉを含有する銅合金からなり、粉末を構成する銅合金粒子の表面にＳｉ濃化層が連続的に形成されていることを特徴としている。 The present invention was made based on the above findings, and the copper alloy powder for metal AM of aspect 1 of the present invention is a copper alloy powder for metal AM used in metal AM, which is made of a copper alloy containing Si, and is characterized in that a Si-enriched layer is continuously formed on the surface of the copper alloy particles that make up the powder.
　本発明の態様１の金属ＡＭ用銅合金粉末によれば、Ｓｉを含有する銅合金からなり、粉末を構成する銅合金粒子の表面にＳｉ濃化層が連続的に形成されていることにより、金属ＡＭにより作製した造形体の微細構造の再現性が高く、ボイド等の構造欠陥が少ない高品質な積層造形物を安定して製造することが可能となる。 The copper alloy powder for metal AM according to aspect 1 of the present invention is made of a copper alloy containing Si, and a Si-enriched layer is continuously formed on the surface of the copper alloy particles that make up the powder. This makes it possible to stably manufacture high-quality additive manufacturing objects with high reproducibility of the microstructure of the objects produced by metal AM and with few structural defects such as voids.
　本発明の態様２は、態様１の金属ＡＭ用銅合金粉末において、前記銅合金はＣｒを含有していることが好ましい。
　本発明の態様２の金属ＡＭ用銅合金粉末によれば、ＣｒとＳｉを含有する銅合金からなり、銅合金粒子の表面にＳｉ濃化層が連続的に形成されていることにより、金属ＡＭにより作製した造形体の微細構造の再現性が高く、ボイド等の構造欠陥が少ない高品質な積層造形物を安定して製造することが可能となる。 In a second aspect of the present invention, in the copper alloy powder for metal AM according to the first aspect, the copper alloy preferably contains Cr.
According to the copper alloy powder for metal AM of aspect 2 of the present invention, which is made of a copper alloy containing Cr and Si, and has a Si-enriched layer continuously formed on the surface of the copper alloy particles, it is possible to stably produce high-quality additively molded objects with high reproducibility of the microstructure of the objects produced by metal AM and with few structural defects such as voids.
　本発明の態様３は、態様１または態様２の金属ＡＭ用銅合金粉末において、前記Ｓｉ濃化層が酸素を含有していることが好ましい。
　本発明の態様３の金属ＡＭ用銅合金粉末によれば、銅合金粒子の表面に形成された前記Ｓｉ濃化層が酸素を含有していることから、金属ＡＭ用銅合金粉末の変質を抑制でき、金属ＡＭにより作製した造形体の微細構造の再現性が高く、ボイド等の構造欠陥が少ない高品質な積層造形物をさらに安定して製造することが可能となる。 In a third aspect of the present invention, in the copper alloy powder for metal AM according to the first or second aspect, the Si-enriched layer preferably contains oxygen.
According to the copper alloy powder for metal AM of aspect 3 of the present invention, since the Si-enriched layer formed on the surface of the copper alloy particles contains oxygen, deterioration of the copper alloy powder for metal AM can be suppressed, and the microstructure of the shaped body produced by metal AM can be highly reproducible, making it possible to more stably produce high-quality additively shaped objects with fewer structural defects such as voids.
　本発明の態様４は、態様１から態様３のいずれか一つの金属ＡＭ用銅合金粉末において、前記銅合金は、Ｃｒを０．１質量％以上０．８質量％以下の範囲内、Ｓｉを０．４質量％以上０．８質量％以下の範囲内、Ｎｉを１．８質量％以上３．０質量％以下の範囲内で含み、その他が銅及び不純物からなる組成とされていることが好ましい。
　本発明の態様４の金属ＡＭ用銅合金粉末によれば、金属ＡＭ用銅合金粉末を構成する銅合金が上述の組成とされているので、この金属ＡＭ用銅合金粉末を用いて作製された積層造形物に対して適切な熱処理を施すことにより、化合物を析出させることができ、導電性、熱伝導性、強度に優れた積層造形物を製造することが可能となる。 In a fourth aspect of the present invention, in the copper alloy powder for metal AM according to any one of the first to third aspects, the copper alloy preferably contains Cr in the range of 0.1 mass % to 0.8 mass %, Si in the range of 0.4 mass % to 0.8 mass %, Ni in the range of 1.8 mass % to 3.0 mass %, and the remainder is copper and impurities.
According to the copper alloy powder for metal AM of aspect 4 of the present invention, the copper alloy constituting the copper alloy powder for metal AM has the above-mentioned composition. Therefore, by subjecting an additive manufacturing object produced using this copper alloy powder for metal AM to an appropriate heat treatment, compounds can be precipitated, making it possible to produce an additive manufacturing object having excellent electrical conductivity, thermal conductivity, and strength.
　本発明の態様５は、態様１から態様４のいずれか一つの金属ＡＭ用銅合金粉末において、レーザー回折・散乱法にて測定された体積基準の５０％累積粒子径Ｄ５０が５μｍ以上１２０μｍ以下の範囲内とされていることが好ましい。
　本発明の態様５の金属ＡＭ用銅合金粉末によれば、レーザー回折・散乱法にて測定された体積基準の５０％累積粒子径Ｄ５０が５μｍ以上１２０μｍ以下の範囲内とされているので、金属ＡＭに適した粒度分布を有しており、積層造形物を安定して製造することが可能となる。 In the fifth aspect of the present invention, in the copper alloy powder for metal AM according to any one of the first to fourth aspects, it is preferable that the volume-based 50% cumulative particle diameter D50 measured by a laser diffraction/scattering method is in the range of 5 μm or more and 120 μm or less.
According to the copper alloy powder for metal AM of aspect 5 of the present invention, the 50% cumulative particle diameter D50 on a volume basis measured by a laser diffraction/scattering method is within the range of 5 μm or more and 120 μm or less, so that the powder has a particle size distribution suitable for metal AM and enables stable production of additive manufacturing objects.
　本発明の態様６は、態様１から態様５のいずれか一つの金属ＡＭ用銅合金粉末において、レーザー回折・散乱法にて測定された体積基準の１０％累積粒子径Ｄ１０が１μｍ以上８０μｍ以下の範囲内とされていることが好ましい。
　本発明の態様６の金属ＡＭ用銅合金粉末によれば、レーザー回折・散乱法にて測定された体積基準の１０％累積粒子径Ｄ１０が１μｍ以上８０μｍ以下の範囲内とされているので、金属ＡＭに適した粒度分布を有しており、積層造形物を安定して製造することが可能となる。 In a sixth aspect of the present invention, in the copper alloy powder for metal AM according to any one of the first to fifth aspects, it is preferable that a 10% cumulative particle diameter D10 on a volume basis measured by a laser diffraction/scattering method is in the range of 1 μm or more and 80 μm or less.
According to the copper alloy powder for metal AM of aspect 6 of the present invention, the volume-based 10% cumulative particle diameter D10 measured by a laser diffraction/scattering method is in the range of 1 μm or more and 80 μm or less, so that it has a particle size distribution suitable for metal AM and enables the stable production of additive manufacturing objects.
　本発明の態様７は、態様１から態様６のいずれか一つの金属ＡＭ用銅合金粉末において、レーザー回折・散乱法にて測定された体積基準の９０％累積粒子径Ｄ９０が１０μｍ以上１５０μｍ以下の範囲内とされていることが好ましい。
　本発明の態様７の金属ＡＭ用銅合金粉末によれば、レーザー回折・散乱法にて測定された体積基準の９０％累積粒子径Ｄ９０が１０μｍ以上１５０μｍ以下の範囲内とされているので、金属ＡＭに適した粒度分布を有しており、積層造形物を安定して製造することが可能となる。 In the seventh aspect of the present invention, in the copper alloy powder for metal AM according to any one of the first to sixth aspects, it is preferable that the volume-based 90% cumulative particle diameter D90 measured by a laser diffraction/scattering method is in the range of 10 μm or more and 150 μm or less.
According to the copper alloy powder for metal AM of aspect 7 of the present invention, the volume-based 90% cumulative particle diameter D90 measured by a laser diffraction/scattering method is in the range of 10 μm or more and 150 μm or less, so that it has a particle size distribution suitable for metal AM and enables the stable production of additive manufacturing objects.
　本発明の態様８の積層造形物の製造方法は、態様１から態様７のいずれか一つの金属ＡＭ用銅合金粉末を準備する準備工程と、前記金属ＡＭ用銅合金粉末を含む粉末床を形成する第１工程と、前記粉末床において所定位置の前記金属ＡＭ用銅合金粉末を固化させて造形床を形成する第２工程とを順次繰り返して積層造形物を作製する造形工程と、を備えることが好ましい。 The method for manufacturing an additively molded object according to aspect 8 of the present invention preferably comprises a preparation step of preparing a copper alloy powder for metal AM according to any one of aspects 1 to 7, a first step of forming a powder bed containing the copper alloy powder for metal AM, and a second step of solidifying the copper alloy powder for metal AM at a predetermined position in the powder bed to form a molding bed, and a molding step of producing an additively molded object by sequentially repeating the steps.
　本発明の態様８の積層造形物の製造方法によれば、態様１から態様７のいずれか一つの金属ＡＭ用銅合金粉末を用いているので、積層造形により作製した造形体の微細構造の再現性が高く、ボイド等の構造欠陥が少ない高品質な積層造形物を安定して製造することが可能となる。 The method for manufacturing an additively molded product according to aspect 8 of the present invention uses a copper alloy powder for metal AM according to any one of aspects 1 to 7, which makes it possible to stably manufacture high-quality additively molded products with high reproducibility of the microstructure of the object produced by additive manufacturing and few structural defects such as voids.
　本発明の態様９の積層造形物の製造方法は、態様８の積層造形物の製造方法において、前記造形工程後に３００℃以上純銅の融点以下の温度範囲で熱処理する熱処理工程を備えていることが好ましい。
　作製した積層造形物の応用に応じた適切な熱処理を施すことにより、造形された銅合金の微細構造を制御することが可能となり、所望の機械特性や導電特性を実現することが可能となる。本発明の態様９の製造方法の温度範囲で熱処理することで、適切に微細構造が制御された銅合金の造形体が実現される。 The method for manufacturing an additively molded object of aspect 9 of the present invention is preferably the method for manufacturing an additively molded object of aspect 8, further comprising a heat treatment step of performing heat treatment at a temperature range of 300°C or higher and lower than the melting point of pure copper after the molding step.
By carrying out an appropriate heat treatment according to the application of the produced additive manufacturing product, it is possible to control the microstructure of the molded copper alloy, and it is possible to realize the desired mechanical properties and conductive properties. By carrying out the heat treatment within the temperature range of the manufacturing method of aspect 9 of the present invention, a copper alloy molded product with an appropriately controlled microstructure is realized.
　本発明の態様１０の積層造形物の製造方法は、態様８の積層造形物の製造方法において、前記造形工程後に８００℃以上純銅の融点以下の温度範囲で熱処理を行う第一熱処理工程と、前記第一熱処理後に３００℃以上８００℃未満の温度範囲で熱処理を行う第二熱処理工程と、を備えていることが好ましい。
　このような温度条件による二段階熱処理を行うことによっても所望の微細構造を有する銅合金が実現可能である。 The manufacturing method of an additively molded object of aspect 10 of the present invention is preferably the same as the manufacturing method of an additively molded object of aspect 8, further comprising a first heat treatment step in which heat treatment is performed in a temperature range of 800°C or higher and lower than the melting point of pure copper after the molding step, and a second heat treatment step in which heat treatment is performed in a temperature range of 300°C or higher and lower than 800°C after the first heat treatment.
By carrying out a two-step heat treatment under such temperature conditions, it is possible to realize a copper alloy having a desired microstructure.
　本発明によれば、金属ＡＭにより作製した造形体の微細構造の再現性が高く、ボイド等の構造欠陥が少ない高品質な積層造形物を安定して製造可能な金属ＡＭ用銅合金粉末、および、積層造形物の製造方法を提供することができる。 The present invention provides a copper alloy powder for metal AM that can stably produce high-quality additively molded objects with high reproducibility of the microstructure of objects produced by metal AM and few structural defects such as voids, and a method for producing additively molded objects.
実施形態である金属ＡＭ用銅合金粉末を構成する銅合金粒子の概略説明図である。FIG. 1 is a schematic explanatory diagram of a copper alloy particle constituting a copper alloy powder for metal AM according to an embodiment. 本実施形態である金属ＡＭ用銅合金粉末の製造方法のフロー図である。FIG. 1 is a flow diagram of a method for producing a copper alloy powder for metal AM according to the present embodiment. 本実施形態である金属ＡＭ用銅合金粉末を製造する際に用いられる連続鋳造装置の概略説明図である。FIG. 1 is a schematic explanatory diagram of a continuous casting device used when producing the copper alloy powder for metal AM according to the present embodiment. 本実施形態である積層造形物の製造方法のフロー図である。FIG. 2 is a flow diagram of a method for producing a layered object according to the present embodiment. 本実施形態である金属ＡＭ用銅合金粉末を製造する際に用いられる他の連続鋳造装置の概略説明図である。FIG. 2 is a schematic explanatory diagram of another continuous casting device used in producing the copper alloy powder for metal AM according to the present embodiment. 本実施形態である金属ＡＭ用銅合金粉末を構成する粒子の最表面近傍のオージェ電子分光分析結果を示す図であり、粒子表面の二次電子像である。1 is a diagram showing the results of Auger electron spectroscopy analysis of the outermost surface of a particle constituting the copper alloy powder for metal AM according to the present embodiment, and is a secondary electron image of the particle surface. 本実施形態である金属ＡＭ用銅合金粉末を構成する粒子の最表面近傍のオージェ電子分光分析結果を示す図であり、粒子表面の元素マッピング像である。FIG. 2 is a diagram showing the results of Auger electron spectroscopy analysis of the outermost surface of a particle constituting the copper alloy powder for metal AM according to the present embodiment, and is an element mapping image of the particle surface. 本実施形態である金属ＡＭ用銅合金粉末を構成する粒子の最表面近傍のオージェ電子分光分析結果を示すグラフの一例であり、Ｏの強度デプスプロファイルを示す。1 is an example of a graph showing the results of Auger electron spectroscopy analysis of the outermost surface of a particle constituting the copper alloy powder for metal AM according to the present embodiment, and shows an O intensity depth profile. 本実施形態である金属ＡＭ用銅合金粉末を構成する粒子の最表面近傍のオージェ電子分光分析結果を示すグラフの一例であり、Ｓｉの強度デプスプロファイルを示す。1 is an example of a graph showing the results of Auger electron spectroscopy analysis of the outermost surface of a particle constituting the copper alloy powder for metal AM according to this embodiment, and shows an intensity depth profile of Si.
　以下に、添付した図面を参照して、本発明の一実施形態である金属ＡＭ用銅合金粉末、および、積層造形物の製造方法について説明する。
　本実施形態である金属ＡＭ用銅合金粉末は、金属ＡＭに用いられる銅合金粉末である。なお、本実施形態である金属ＡＭ用銅合金粉末においては、レーザーＰＢＦ法に特に適したものとされている。 Hereinafter, a copper alloy powder for metal AM according to one embodiment of the present invention and a method for manufacturing an additive manufacturing product will be described with reference to the accompanying drawings.
The copper alloy powder for metal AM according to the present embodiment is a copper alloy powder used for metal AM. Note that the copper alloy powder for metal AM according to the present embodiment is considered to be particularly suitable for the laser PBF method.
　本実施形態である金属ＡＭ用銅合金粉末は、Ｓｉを含有する銅合金で構成されている粒子の集合体であり、金属ＡＭ用銅合金粉末を構成する銅合金粒子の表面にはＳｉ濃化層が連続的に形成されている。すなわち、本実施形態である金属ＡＭ用銅合金粉末の銅合金粒子５０においては、図１に示すように、Ｓｉを含有する銅合金からなる粒子本体（銅合金粒子）５１と、この粒子本体５１の表面（或いは表層）に形成されたＳｉ濃化層５２と備えたものとされている。なお、本実施形態において、金属ＡＭ用銅合金粉末の銅合金粒子の表面（粒子表面）（或いは表層）は、粒子の最表面から深さ１００ｎｍまでの領域である。 The copper alloy powder for metal AM of this embodiment is an aggregate of particles made of a copper alloy containing Si, and a Si-concentrated layer is continuously formed on the surface of the copper alloy particles that make up the copper alloy powder for metal AM. That is, as shown in FIG. 1, the copper alloy particle 50 of the copper alloy powder for metal AM of this embodiment has a particle body (copper alloy particle) 51 made of a copper alloy containing Si, and a Si-concentrated layer 52 formed on the surface (or surface layer) of this particle body 51. In this embodiment, the surface (particle surface) (or surface layer) of the copper alloy particle of the copper alloy powder for metal AM is a region from the outermost surface of the particle to a depth of 100 nm.
　Ｓｉ濃化層５２とは、以下で定義するＳｉ強度倍率因子(Si intensity amplification factor）が２以上である部分が、粒子本体５１の表面に対するオージェ電子分光分析の結果から解析される層である。この解析方法を以下に説明する。
　アルバック・ファイ株式会社製走査型オージェ電子分光分析装置ＰＨＩ７００xiを用い、分析目的の粒子本体５１の表面のオージェ電子信号計測開始から３０秒毎に、計測時間(t)に伴うＳｉ元素の信号強度（IAES(t)）を測定する。 The Si-enriched layer 52 is a layer in which a portion having a Si intensity amplification factor (defined below) of 2 or more is analyzed from the results of Auger electron spectroscopy on the surface of the particle body 51. This analysis method will be described below.
Using a scanning Auger electron spectrometer PHI700xi manufactured by ULVAC-PHI, Inc., the signal intensity of Si element (IAES(t)) over measurement time (t) is measured every 30 seconds from the start of Auger electron signal measurement on the surface of the particle body 51 to be analyzed.
　オージェ電子分光分析によるＳｉ濃化層５２の同定は以下のように行う。分析目的の粒子表面のオージェ電子信号計測開始から３０秒毎に、計測時間(t)に伴うＳｉ元素の信号強度（IAES(t)）を測定する。そして、Ｓｉ元素に関するIAES(t)が概ね一定になる領域を６点以上確認し、これらのIAES(t)が一定となる領域において、IAES(t)の平均値を算出する。この平均値を平均バックグラウンド強度（IAES,BG AVE）と定義する。次に、取得した全てのtにおけるIAES(t)をIAES,BG AVEで除した数値を求める。この数値をIAES, NORM(t)と定義する。IAES, NORM(t)は以下の式（１）により表される。
　IAES, NORM(t) ＝ IAES(t) / IAES,BG AVE　　　式（１） The Si-enriched layer 52 is identified by Auger electron spectroscopy as follows. The signal intensity (I AES (t)) of the Si element is measured over the measurement time (t) every 30 seconds from the start of Auger electron signal measurement on the particle surface to be analyzed. Six or more regions where the I AES (t) for the Si element is roughly constant are then identified, and the average value of I AES (t) is calculated in these regions where the I AES (t) is constant. This average value is defined as the average background intensity (I AES , BG AVE ). Next, the I AES (t) at all the acquired times t is divided by the I AES , BG AVE to obtain a numerical value. This numerical value is defined as I AES, NORM (t). I AES, NORM (t) is expressed by the following formula (1).
I AES, NORM (t) = I AES (t) / I AES , BG AVE Equation (1)
　t- IAES,NORM(t)関係において、Ｓｉ濃化層５２では計測時間の低下と共にIAES,NORM(t)が連続的に増大する。このIAES,NORM(t)の連続的な増加が観測される領域の開始時間をＳｉ濃化層の末端となる時間ts0と定義する。
　例えば、実施例において（後述の表５を参照）、ts0は概ね２ｍｉｎとなる。また、式（１）により算出するIAES, NORM(t)を、Ｓｉ強度倍率因子(Si intensity amplification factor）とよぶ。表５によれば、Ｓｉ濃化層５２が存在する実施例において、Ｓｉ強度倍率因子が２を超える数値が明確に観測され、Ｓｉ信号強度がバックグラウンド強度に対して明らかに強くなる状況が確認される。 In the t-I AES,NORM (t) relationship, I AES,NORM (t) increases continuously with decreasing measurement time in the Si-enriched layer 52. The start time of the region where this continuous increase in I AES,NORM (t) is observed is defined as the time t s0 which marks the end of the Si-enriched layer.
For example, in an embodiment (see Table 5 described later), ts0 is approximately 2 min. Furthermore, I AES,NORM (t) calculated by formula (1) is called the Si intensity amplification factor. According to Table 5, in an embodiment in which the Si-enriched layer 52 is present, a value of the Si intensity amplification factor exceeding 2 is clearly observed, and a situation in which the Si signal intensity is clearly stronger than the background intensity is confirmed.
　そこで本実施形態では、粒子本体５１の表面にＳｉ強度倍率因子が２以上、好ましくは２を超えている部分が複数観察される場合、粒子本体５１の表面にＳｉ濃化層５２が存在すると定義とした。
　なお、Ｓｉ濃化層５２では、図７Ｂで示すようにＳｉ濃度の傾斜が観察されることから、Ｓｉ濃化層５２の一部に、Ｓｉ強度倍率因子が２未満～１．７等の箇所が観察されてもよい。 Therefore, in this embodiment, when multiple areas are observed on the surface of the particle body 51 where the Si intensity magnification factor is 2 or more, preferably exceeds 2, it is defined that a Si-enriched layer 52 is present on the surface of the particle body 51.
In addition, since a gradient of the Si concentration is observed in the Si-enriched layer 52 as shown in FIG. 7B, a portion of the Si-enriched layer 52 may have a Si intensity magnification factor of less than 2 to 1.7, for example.
　本実施形態では、金属ＡＭ用銅合金粉末の銅合金粒子５０の粒子本体５１の表面に形成されたＳｉ濃化層５２が酸素（Ｏ）を含むものとされていることが好ましい。
　また、粒子本体５１の表面に形成されたＳｉ濃化層５２の厚みは、１ｎｍ以上１００ｎｍ以下となっていることが好ましい。
　Ｓｉ濃化層５２の厚みは、１ｎｍ以上が好ましく、５ｎｍ以上であってもよく、１０ｎｍ以上であってもよく、２０ｎｍ以上であってもよく、３０ｎｍ以上であってもよく、５０ｎｍ以上であってもよい。また、Ｃｒ化合物層５２の厚みは、１００ｎｍ以下であることが好ましく、９５ｎｍ以下であってもよく、９０ｎｍ以下であってもよく、８０ｎｍ以下であってもよく、７０ｎｍ以下であってもよい。 In this embodiment, it is preferable that the Si-enriched layer 52 formed on the surface of the particle body 51 of the copper alloy particle 50 of the copper alloy powder for metal AM contains oxygen (O).
The thickness of the Si-enriched layer 52 formed on the surface of the particle body 51 is preferably 1 nm or more and 100 nm or less.
The thickness of the Si-enriched layer 52 is preferably 1 nm or more, and may be 5 nm or more, 10 nm or more, 20 nm or more, 30 nm or more, or 50 nm or more. The thickness of the Cr compound layer 52 is preferably 100 nm or less, and may be 95 nm or less, 90 nm or less, 80 nm or less, or 70 nm or less.
　Ｓｉ濃化層５２の厚みは、ＳｉＯ２からなる粒子表面をイオンエッチング法で、エッチングレート１．０８ｎｍ／分でエッチングを行う条件を基準の条件とし、この基準のエッチング条件で、金属ＡＭ用銅合金粉末の銅合金粒子５０の表面をエッチングして、金属ＡＭ用銅合金粉末の銅合金粒子５０の表面を、アルバック・ファイ株式会社製走査型オージェ電子分光分析装置ＰＨＩ７００xiを用いたオージェ電子分光法によって分析し、Ｓｉ化合物を示すＳｉマッピング像を得て、ケイ素（Ｓｉ）の強度デプスプロファイル（図７Ｂに示す、強度－エッチング時間の関係を示すグラフ）を得て、ケイ素（Ｓｉ）の強度（cps）が、減少しなくなるまで又は所定の値以下となる時間から算出できる。
　すなわち、ケイ素（Ｓｉ）の強度（cps）が所定の値以下となる時間（分）×基準の条件のエッチングレート１．０８ｎｍ／分＝Ｃｒ化合物層５２の厚み、として算出できる。 The thickness of the Si-enriched layer 52 is determined by etching the surface of the copper alloy particles 50 of the copper alloy powder for metal AM by ion etching at an etching rate of 1.08 nm/min under the standard etching conditions, and analyzing the surface of the copper alloy particles 50 of the copper alloy powder for metal AM by Auger electron spectroscopy using a scanning Auger electron spectrometer PHI700xi manufactured by ULVAC-PHI, Inc. to obtain a Si mapping image showing the Si compound, and obtaining a silicon (Si) intensity depth profile (a graph showing the relationship between intensity and etching time shown in FIG. 7B). The thickness of the Si-enriched layer 52 can be calculated from the time until the silicon (Si) intensity (cps) stops decreasing or becomes equal to or less than a predetermined value.
That is, it can be calculated as follows: time (minutes) until the strength (cps) of silicon (Si) becomes equal to or lower than a predetermined value × etching rate under standard conditions 1.08 nm/minute = thickness of the Cr compound layer 52 .
　本実施形態である金属ＡＭ用銅合金粉末の銅合金粒子５０を構成する銅合金は、合金元素としてＣｒを含有することが好ましい。これは、銅合金にＣｒが添加されることにより、銅合金中にＣｒとＳｉの化合物が生成し、特に銅合金粒子の表面に存在するＣｒとＳｉの化合物がレーザー吸収率を改善するのに貢献するためである。 The copper alloy constituting the copper alloy particles 50 of the copper alloy powder for metal AM of this embodiment preferably contains Cr as an alloying element. This is because the addition of Cr to the copper alloy produces compounds of Cr and Si in the copper alloy, and in particular the compounds of Cr and Si present on the surface of the copper alloy particles contribute to improving the laser absorption rate.
　本実施形態である金属ＡＭ用銅合金粉末の銅合金粒子５０を構成する銅合金は、合金元素としてＮｉを含有することが好ましい。これは、銅合金にＮｉが添加されることによりＮｉがＣｕ結晶粒内に固溶し、銅合金粒子中のＣｕ結晶粒のレーザー吸収率を改善するのに貢献するためである。ここで、合金元素として含有するＮｉの含有量は、３．０質量％以下が好ましい。
　また、本実施形態である金属ＡＭ用銅合金粉末の銅合金粒子５０を構成する銅合金は、合金元素として、Ｃｒを０．１質量％以上０．８質量％以下の範囲内、Ｓｉを０．４質量％以上０．８質量％以下の範囲内、Ｎｉを１．８質量％以上３．０質量％以下の範囲内で含み、その他が銅及び不純物からなる組成とされていることが好ましい。すなわち、本実施形態である金属ＡＭ用銅合金粉末の銅合金粒子５０を構成する銅合金は、Ｃ１８０００に相当する組成とされていることが好ましい。 The copper alloy constituting the copper alloy particles 50 of the copper alloy powder for metal AM of this embodiment preferably contains Ni as an alloying element. This is because the addition of Ni to the copper alloy causes Ni to dissolve in the Cu crystal grains, which contributes to improving the laser absorptivity of the Cu crystal grains in the copper alloy particles. Here, the content of Ni contained as an alloying element is preferably 3.0 mass% or less.
In addition, the copper alloy constituting the copper alloy particles 50 of the copper alloy powder for metal AM of this embodiment preferably contains, as alloy elements, Cr in the range of 0.1 mass% to 0.8 mass%, Si in the range of 0.4 mass% to 0.8 mass%, Ni in the range of 1.8 mass% to 3.0 mass%, and the rest is composed of copper and impurities. That is, the copper alloy constituting the copper alloy particles 50 of the copper alloy powder for metal AM of this embodiment preferably has a composition equivalent to C18000.
　本実施形態において、合金元素とは、Ｃｒ、Ｓｉ、及びＮｉをいう。また、ここで不純物とは、後述する不純物元素とＯ，Ｈ，Ｓ，及びＮを含む成分である。
　金属ＡＭ用銅合金粉末の銅合金粒子５０を構成する銅合金の組成において、数字の精度の誤差は±１０％である（Ｏ，Ｈ，Ｓ，及びＮを除く）。 In this embodiment, the alloy elements refer to Cr, Si, and Ni. The impurities referred to here are components including impurity elements described below as well as O, H, S, and N.
In the composition of the copper alloy constituting the copper alloy particles 50 of the copper alloy powder for metal AM, the numerical accuracy error is ±10% (excluding O, H, S, and N).
　なお、Ｃｒの含有量の下限は０．２質量％以上であることがさらに好ましく、０．３質量％以上であることがより好ましい。Ｃｒの含有量の上限は０．８質量％以下であることがさらに好ましく、０．７質量％以下であることがより好ましい。
　Ｓｉの含有量の下限は０．４５質量％以上であることがさらに好ましく、０．５質量％以上であることがより好ましい。Ｓｉの含有量の上限は０．７質量％以下であることがさらに好ましく、０．６質量％以下であることがより好ましい。
　Ｎｉの含有量の下限は１．９質量％以上であることがさらに好ましく、２．０質量％以上であることがより好ましい。Ｎｉの含有量の上限は２．９質量％以下であることがさらに好ましく、２．８質量％以下であることがより好ましい。 The lower limit of the Cr content is more preferably 0.2 mass% or more, and even more preferably 0.3 mass% or more. The upper limit of the Cr content is more preferably 0.8 mass% or less, and even more preferably 0.7 mass% or less.
The lower limit of the Si content is more preferably 0.45 mass% or more, and even more preferably 0.5 mass% or more. The upper limit of the Si content is more preferably 0.7 mass% or less, and even more preferably 0.6 mass% or less.
The lower limit of the Ni content is more preferably 1.9 mass% or more, and even more preferably 2.0 mass% or more. The upper limit of the Ni content is more preferably 2.9 mass% or less, and even more preferably 2.8 mass% or less.
　また、金属ＡＭ用銅合金粉末の銅合金粒子５０を構成する銅合金は、合金元素以外の添加元素および不純物元素（Ｏ，Ｈ，Ｓ，及びＮを除く）を含んでいてもよい。
　本実施形態において添加元素とは、本実施形態の金属ＡＭ用銅合金粉末の銅合金粒子５０に意図的に添加される元素である。一方、不純物元素（Ｏ，Ｈ，Ｓ，及びＮを除く）とは、本実施形態の金属ＡＭ用銅合金粉末の銅合金粒子５０に意図せずに混入するものであり、製造工程中のコンタミネーションや原料に微量に含有される不純物に由来する。不純物元素は不可避不純物であってもよい。 In addition, the copper alloy constituting the copper alloy particles 50 of the copper alloy powder for metal AM may contain additive elements and impurity elements (excluding O, H, S, and N) other than the alloy elements.
In this embodiment, the additive elements are elements that are intentionally added to the copper alloy particles 50 of the copper alloy powder for metal AM of this embodiment. On the other hand, the impurity elements (excluding O, H, S, and N) are elements that are unintentionally mixed into the copper alloy particles 50 of the copper alloy powder for metal AM of this embodiment, and originate from contamination during the manufacturing process or impurities contained in trace amounts in the raw materials. The impurity elements may be unavoidable impurities.
　金属ＡＭ用銅合金粉末の銅合金粒子５０を構成する合金元素以外の添加元素および不純物元素（Ｏ，Ｈ，Ｓ，及びＮを除く）としては、例えば、Ｚｒ、Ｍｇ、Ｔｉ、Ａｌ、Ｚｎ、Ｃａ、Ｓｎ、Ｐｂ、Ｆｅ、Ｍｎ、Ｔｅ、Ｎｂ，Ｐ、Ｃｏ、Ｓｂ、Ｂｉ、Ａｇ，Ｔａ，Ｗ，及びＭｏ等を挙げることができる。なお、合金元素以外の添加元素および不純物元素（Ｏ，Ｈ，Ｓ，及びＮを除く）は、Ｚｒ、Ｍｇ、Ｔｉ、Ａｌ、Ｚｎ、Ｃａ、Ｓｎ、Ｐｂ、Ｆｅ、Ｍｎ、Ｔｅ、Ｎｂ，Ｐ、Ｃｏ、Ｓｂ、Ｂｉ、及びＡｇ，Ｔａ，Ｗ，及びＭｏ等の群から選択される少なくとも一種の元素を含んでいてもよい。
　ここで、金属ＡＭ用銅合金粉末の銅合金粒子５０を構成する合金元素以外の添加元素および不純物元素（Ｏ，Ｈ，Ｓ，及びＮを除く）は、総量で０．０７ｍａｓｓ％以下であってもよく、０．０６ｍａｓｓ％以下であってもよく、０．０５ｍａｓｓ％以下であってもよく、０．０４ｍａｓｓ％以下とすることが好ましく、０．０３ｍａｓｓ％以下とすることがさらに好ましく、０．０２ｍａｓｓ％以下とすることがより好ましく、さらには０．０１ｍａｓｓ％以下とすることが好ましい。
　また、金属ＡＭ用銅合金粉末の銅合金粒子５０を構成する合金元素以外の添加元素および不純物元素（Ｏ，Ｈ，Ｓ，及びＮを除く）のそれぞれの含有量の上限は、３０ｍａｓｓｐｐｍ以下とすることが好ましく、２０ｍａｓｓｐｐｍ以下とすることがさらに好ましく、１５ｍａｓｓｐｐｍ以下とすることがより好ましい。 Examples of additive elements and impurity elements (excluding O, H, S, and N) other than the alloy elements constituting the copper alloy particles 50 of the copper alloy powder for metal AM include Zr, Mg, Ti, Al, Zn, Ca, Sn, Pb, Fe, Mn, Te, Nb, P, Co, Sb, Bi, Ag, Ta, W, and Mo. The additive elements and impurity elements (excluding O, H, S, and N) other than the alloy elements may include at least one element selected from the group consisting of Zr, Mg, Ti, Al, Zn, Ca, Sn, Pb, Fe, Mn, Te, Nb, P, Co, Sb, Bi, and Ag, Ta, W, and Mo.
Here, the total amount of additive elements and impurity elements (excluding O, H, S, and N) other than the alloy elements constituting the copper alloy particles 50 of the copper alloy powder for metal AM may be 0.07 mass% or less, 0.06 mass% or less, or 0.05 mass% or less, preferably 0.04 mass% or less, more preferably 0.03 mass% or less, even more preferably 0.02 mass% or less, and even more preferably 0.01 mass% or less.
In addition, the upper limit of the content of each of the additive elements and impurity elements (excluding O, H, S, and N) other than the alloy elements constituting the copper alloy particles 50 of the copper alloy powder for metal AM is preferably 30 ppm by mass or less, more preferably 20 ppm by mass or less, and even more preferably 15 ppm by mass or less.
　本実施形態である金属ＡＭ用銅合金粉末においては、レーザー回折・散乱法にて測定された体積基準の５０％累積粒子径Ｄ５０が５μｍ以上１２０μｍ以下の範囲内、１０％累積粒子径Ｄ１０が１μｍ以上８０μｍ以下の範囲内、９０％累積粒子径Ｄ９０が１０μｍ以上１５０μｍ以下の範囲内とされていることが好ましい。 In the copper alloy powder for metal AM according to this embodiment, it is preferable that the 50% cumulative particle diameter D50 on a volume basis measured by a laser diffraction/scattering method is in the range of 5 μm or more and 120 μm or less, the 10% cumulative particle diameter D10 is in the range of 1 μm or more and 80 μm or less, and the 90% cumulative particle diameter D90 is in the range of 10 μm or more and 150 μm or less.
　なお、５０％累積粒子径Ｄ５０の下限は１０μｍ以上であることがさらに好ましく、１５μｍ以上であることがより好ましい。５０％累積粒子径Ｄ５０の上限は１００μｍ以下であることがさらに好ましく、９０μｍ以下であることがより好ましい。
　また、１０％累積粒子径Ｄ１０の下限は５μｍ以上であることがさらに好ましく、１０μｍ以上であることがより好ましい。１０％累積粒子径Ｄ１０の上限は７０μｍ以下であることがさらに好ましく、６０μｍ以下であることがより好ましい。
　さらに、９０％累積粒子径Ｄ９０の下限は２０μｍ以上であることがさらに好ましく、３０μｍ以上であることがより好ましい。９０％累積粒子径Ｄ９０の上限は１４０μｍ以下であることがさらに好ましく、１２０μｍ以下であることがより好ましい。 The lower limit of the 50% cumulative particle size D50 is more preferably 10 μm or more, and even more preferably 15 μm or more. The upper limit of the 50% cumulative particle size D50 is more preferably 100 μm or less, and even more preferably 90 μm or less.
The lower limit of the 10% cumulative particle size D10 is more preferably 5 μm or more, and even more preferably 10 μm or more. The upper limit of the 10% cumulative particle size D10 is more preferably 70 μm or less, and even more preferably 60 μm or less.
Furthermore, the lower limit of the 90% cumulative particle size D90 is more preferably 20 μm or more, and even more preferably 30 μm or more. The upper limit of the 90% cumulative particle size D90 is more preferably 140 μm or less, and even more preferably 120 μm or less.
　本実施形態である金属ＡＭ用銅合金粉末の製造方法の一例について、図２のフロー図を用いて説明する。なお、本実施形態では、レーザーＰＢＦ法に適した銅合金粉末を製造するものである。
　本実施形態である金属ＡＭ用銅合金粉末の製造方法は、銅合金鋳塊を得る溶解・鋳造工程Ｓ０１と、得られた銅合金鋳塊を線棒材に加工して銅合金原料とする銅合金原料作製工程Ｓ０２と、銅合金原料を粉末に加工する粉末加工工程Ｓ０３と、を備えている。 An example of the method for producing copper alloy powder for metal AM according to the present embodiment will be described with reference to the flow diagram of Fig. 2. Note that, in this embodiment, copper alloy powder suitable for the laser PBF method is produced.
The manufacturing method of copper alloy powder for metal AM according to this embodiment includes a melting and casting step S01 for obtaining a copper alloy ingot, a copper alloy raw material preparation step S02 for processing the obtained copper alloy ingot into a wire rod to obtain a copper alloy raw material, and a powder processing step S03 for processing the copper alloy raw material into powder.
（溶解・鋳造工程Ｓ０１）
　まず、所定組成の銅合金鋳塊を製造する。溶解・鋳造工程Ｓ０１においては、溶解工程、合金元素添加工程、連続鋳造工程を有している。ここで、本実施形態においては、図３に示す連続鋳造装置１０を用いて銅合金鋳塊１を製造する。
　この連続鋳造装置１０は、溶解炉１１と、溶解炉１１の下流に配置されたタンディシュ１２と、溶解炉１１とタンディシュ１２とをつなぐ連結樋１３と、タンディシュ１２において合金元素を添加する添加部１４と、タンディッシュ１２の下流側に配設された連続鋳造用鋳型１５と、タンディッシュ１２から連続鋳造用鋳型１５へと銅合金溶湯を注入する注湯ノズル１６と、を備えている。 (Melting and casting process S01)
First, a copper alloy ingot having a predetermined composition is produced. The melting and casting process S01 includes a melting step, an alloying element addition step, and a continuous casting step. In this embodiment, a copper alloy ingot 1 is produced using a continuous casting apparatus 10 shown in FIG.
This continuous casting apparatus 10 includes a melting furnace 11, a tundish 12 arranged downstream of the melting furnace 11, a connecting trough 13 connecting the melting furnace 11 and the tundish 12, an addition section 14 for adding alloy elements in the tundish 12, a continuous casting mold 15 arranged downstream of the tundish 12, and a pouring nozzle 16 for pouring molten copper alloy from the tundish 12 into the continuous casting mold 15.
　溶解炉１１においては、非酸化性雰囲気（不活性ガス雰囲気または還元性雰囲気）で、銅原料を溶解して銅溶湯３を得る（溶解工程）。
　ここで、溶解炉１１において溶解する銅原料は、銅の純度が９９．９９ｍａｓｓ％以上の高純度銅（例、高純度の電気銅や無酸素銅）とされている。なお、溶解する銅原料は、４Ｎグレード（９９．９９ｍａｓｓ％）以上の高純度銅であるが、５Ｎグレード（９９．９９９ｍａｓｓ％）以上の高純度銅であることがより好ましく、６Ｎ（９９．９９９９ｍａｓｓ％）以上の高純度銅であることがさらに好ましい。また、得られる銅溶湯３は無酸素銅溶湯であることが好ましい。 In the melting furnace 11, the copper raw material is melted in a non-oxidizing atmosphere (an inert gas atmosphere or a reducing atmosphere) to obtain molten copper 3 (melting step).
Here, the copper raw material melted in the melting furnace 11 is high-purity copper having a purity of 99.99 mass% or more (e.g., high-purity electrolytic copper or oxygen-free copper). The copper raw material to be melted is high-purity copper of 4N grade (99.99 mass%) or more, more preferably high-purity copper of 5N grade (99.999 mass%) or more, and even more preferably high-purity copper of 6N (99.9999 mass%) or more. In addition, the obtained molten copper 3 is preferably oxygen-free molten copper.
　連結樋１３においては、得られた銅溶湯３を、非酸化性雰囲気（不活性ガス雰囲気または還元性雰囲気）を維持した状態で、タンディッシュ１２に供給する。連結樋１３は溶解炉１１とタンディッシュ１２との間に配置され、銅溶湯３は非酸化性雰囲気の連結樋１３内を通過する。
　また、タンディッシュ１２内においては、非酸化性雰囲気（不活性ガス雰囲気または還元性雰囲気）にて、銅溶湯３を保持する。
　なお、溶解炉１１、連結樋１３、タンディッシュ１２が、非酸化性雰囲気（不活性ガス雰囲気または還元性雰囲気）とされていることから、銅溶湯３中のガス成分（Ｏ，Ｈ）が低減されることになる。 In the connecting trough 13, the obtained molten copper 3 is supplied to the tundish 12 while maintaining a non-oxidizing atmosphere (an inert gas atmosphere or a reducing atmosphere). The connecting trough 13 is disposed between the melting furnace 11 and the tundish 12, and the molten copper 3 passes through the inside of the connecting trough 13 in a non-oxidizing atmosphere.
In addition, in the tundish 12, the molten copper 3 is held in a non-oxidizing atmosphere (an inert gas atmosphere or a reducing atmosphere).
In addition, since the melting furnace 11, the connecting trough 13, and the tundish 12 are in a non-oxidizing atmosphere (an inert gas atmosphere or a reducing atmosphere), the gas components (O, H) in the molten copper 3 are reduced.
　そして、タンディッシュ１２においては、銅溶湯３に対して添加部１４を用いて合金元素（Ｃｒ、Ｓｉ、及びＮｉ等）を適宜添加する（合金元素添加工程）。また、ここで添加元素を適宜添加してもよい。
　ガス成分（Ｏ，Ｈ）が十分低減された銅溶湯３に対して合金元素を添加することにより、合金元素の添加歩留が良いので、合金元素の使用量を低減でき、銅合金の製造コストを低減することができる。
　また、タンディッシュ１２内を流動している銅溶湯３に対して合金元素を添加することにより、合金元素を均一に溶解して、成分値が安定した銅合金溶湯を連続的に製造することができる。 In the tundish 12, alloy elements (Cr, Si, Ni, etc.) are appropriately added to the molten copper 3 using the adding section 14 (alloy element adding step). Also, additive elements may be appropriately added here.
By adding alloying elements to the molten copper 3 in which the gas components (O, H) have been sufficiently reduced, the yield of the alloying elements added is good, so that the amount of the alloying elements used can be reduced, and the manufacturing cost of the copper alloy can be reduced.
Furthermore, by adding alloying elements to the molten copper 3 flowing inside the tundish 12, the alloying elements can be uniformly dissolved, and a molten copper alloy having stable component values can be continuously produced.
　得られた銅合金溶湯を、注湯ノズル１６を介して連続鋳造鋳型１５に注入し、銅合金鋳塊１を連続的に製造する（連続鋳造工程）。
　なお、本実施形態では、断面円形の銅合金鋳塊を製造するものとしている。 The obtained molten copper alloy is poured into a continuous casting mold 15 through a pouring nozzle 16 to continuously produce a copper alloy ingot 1 (continuous casting process).
In this embodiment, a copper alloy ingot having a circular cross section is produced.
　ここで、本実施形態では、得られた銅合金鋳塊１においては、Ｏ濃度が１０ｍａｓｓｐｐｍ以下、Ｈ濃度が５ｍａｓｓｐｐｍ以下とされている。
　なお、得られた銅合金鋳塊１においては、Ｓ濃度が１５ｍａｓｓｐｐｍ以下とされていることが好ましい。
　さらに、得られた銅合金鋳塊１においては、Ｃｕと合金元素以外の不純物元素の含有量は合計で０．０４ｍａｓｓ％以下であることが好ましい。
　また、得られた銅合金鋳塊１においては、Ｏ濃度とＨ濃度とＳ濃度の合計が２０ｍａｓｓｐｐｍ以下とされていることが好ましい。 In this embodiment, the obtained copper alloy ingot 1 has an O concentration of 10 ppm by mass or less and an H concentration of 5 ppm by mass or less.
In the obtained copper alloy ingot 1, the S concentration is preferably 15 mass ppm or less.
Furthermore, in the obtained copper alloy ingot 1, the total content of impurity elements other than Cu and alloy elements is preferably 0.04 mass% or less.
In the obtained copper alloy ingot 1, the total concentration of O, H and S is preferably 20 mass ppm or less.
（銅合金原料作製工程Ｓ０２）
　次に、溶解・鋳造工程Ｓ０１で得られた銅合金鋳塊を線棒材に加工して、銅合金原料を製造する。銅合金原料作製工程Ｓ０２においては、押出工程と、引抜工程と、切断工程と、を備えている。
　この銅合金原料作製工程Ｓ０２においては、まず、断面円形の銅合金鋳塊を加熱し、熱間押出加工によって、所定の直径の棒材とする（押出工程）。
　なお、本実施形態においては、熱間押出加工時の加熱温度を７００℃以上１０００℃以下の範囲内とすることが好ましい。 (Copper alloy raw material preparation step S02)
Next, the copper alloy ingot obtained in the melting and casting step S01 is processed into a wire rod to produce a copper alloy raw material. The copper alloy raw material preparation step S02 includes an extrusion step, a drawing step, and a cutting step.
In this copper alloy raw material preparation step S02, first, a copper alloy ingot having a circular cross section is heated and processed by hot extrusion into a rod having a predetermined diameter (extrusion step).
In this embodiment, the heating temperature during the hot extrusion process is preferably set within a range of 700° C. or more and 1000° C. or less.
　次に、得られた棒材に対して引抜加工を行って、所定の直径の線材とする（引抜工程）。なお、引抜加工の温度には特に制限はないが、冷間または温間圧延となる－２００℃から２００℃の範囲内とすることが好ましく、特に常温が好ましい。 Then, the obtained rod is subjected to drawing to produce a wire of a specified diameter (drawing process). There are no particular restrictions on the temperature of the drawing process, but it is preferable to carry out the process at a temperature between -200°C and 200°C, which results in cold or warm rolling, and room temperature is particularly preferable.
　そして、得られた線材を所定の長さに切断し、銅合金原料とする（切断工程）。
　ここで、得られた銅合金原料におけるＯ濃度が１０ｍａｓｓｐｐｍ以下、Ｈ濃度が５ｍａｓｓｐｐｍ以下であることが好ましい。
　また、得られた銅合金原料におけるＳ濃度が１５ｍａｓｓｐｐｍ以下であることが好ましい。
　さらに、得られた銅合金原料におけるＣｕと合金元素以外の不純物元素（Ｏ，Ｈ，及びＳを除く）の含有量は合計で０．０４ｍａｓｓ％以下であることが好ましい。 The resulting wire is then cut to a predetermined length to provide a copper alloy raw material (cutting step).
Here, it is preferable that the obtained copper alloy raw material has an O concentration of 10 mass ppm or less and an H concentration of 5 mass ppm or less.
In addition, the S concentration in the obtained copper alloy raw material is preferably 15 mass ppm or less.
Furthermore, the total content of impurity elements (excluding O, H, and S) other than Cu and alloy elements in the obtained copper alloy raw material is preferably 0.04 mass% or less.
（粉末加工工程Ｓ０３）
　次に、銅合金原料作製工程Ｓ０２で得られた銅合金原料を用いて、アトマイズ処理することにより、金属ＡＭ用銅合金粉末を製造する。
　この粉末加工工程Ｓ０３においては、溶解工程と、アトマイズ処理工程と、分級工程と、を備えている。
　この溶解工程では、銅合金原料を加熱して溶解して合金溶湯を得る。ここで、本実施形態では、溶解時の雰囲気は非酸化雰囲気とすることが好ましい。
　アトマイズ処理工程では、例えばガスアトマイズ法によって粉末を得る。すなわち、溶解工程で得られた合金溶湯を、高圧ガス噴霧して合金溶湯の液滴を急冷することで、球状または球状に類似する形状の粉末を製造する。ガスアトマイズ法に用いられるガスとしては、アルゴン、窒素などの不活性ガスを利用可能である。
　分級工程では、得られた粉末を分級処理し、所定の粒度分布を有する銅合金粉末を得る。ガスアトマイズ処理における銅合金原料の溶解温度（ガスアトマイズ処理時の溶解温度）は銅の融点以上、１５００℃以下であることが好ましい。ガスアトマイズ処理時の溶解温度は、１０８５℃以上、１５００℃以下であってもよい。 (Powder processing step S03)
Next, the copper alloy raw material obtained in the copper alloy raw material preparation step S02 is subjected to an atomization process to produce copper alloy powder for metal AM.
This powder processing step S03 includes a melting step, an atomizing step, and a classification step.
In the melting step, the copper alloy raw material is heated and melted to obtain a molten alloy. In this embodiment, the melting atmosphere is preferably a non-oxidizing atmosphere.
In the atomization process, powder is obtained by, for example, gas atomization. That is, the molten alloy obtained in the melting process is sprayed with high-pressure gas to rapidly cool the droplets of the molten alloy, thereby producing powder having a spherical or similar shape. Inert gases such as argon and nitrogen can be used as the gas used in the gas atomization process.
In the classification step, the obtained powder is classified to obtain a copper alloy powder having a predetermined particle size distribution. The melting temperature of the copper alloy raw material in the gas atomization process (the melting temperature during the gas atomization process) is preferably equal to or higher than the melting point of copper and equal to or lower than 1500° C. The melting temperature during the gas atomization process may be equal to or higher than 1085° C. and equal to or lower than 1500° C.
　上述の各工程により、本実施形態である金属ＡＭ用銅合金粉末が製造される。なお、本実施形態である金属ＡＭ用銅合金粉末においては、Ｏ濃度が１０００ｍａｓｓｐｐｍ以下、Ｈ濃度が５ｍａｓｓｐｐｍ以下であることが好ましい。また、Ｓ濃度が１０ｍａｓｓｐｐｍ以下であることが好ましい。
　詳しくは、Ｏ濃度は２７００ｍａｓｓｐｐｍ以下程度であってもよく、１０００ｍａｓｓｐｐｍ以下であると好ましく、９００ｍａｓｓｐｐｍ以下であることがより好ましい。また、Ｏ濃度の下限値は特に限定されないが、０を含まない値で（又は０を超える値）あってよい。
　Ｏ濃度が高いと造形体に酸素や酸化物などの形で異物が残存し、造形体の各種特性を悪化させる可能性がある。
　Ｈ濃度は９０ｍａｓｓｐｐｍ以下であってもよく、６０ｍａｓｓｐｐｍ以下であってもよく、５ｍａｓｓｐｐｍ以下であることが好ましい。また、Ｈ濃度の下限値は特に限定されないが、０を含まない値で（又は０を超える値）あってよい。
　Ｓ濃度は、９０ｍａｓｓｐｐｍ以下であってもよく、６０ｍａｓｓｐｐｍ以下であってもよく、３０ｍａｓｓｐｐｍ以下であると好ましい。更に、金属ＡＭ用銅合金粉末におけるＳ濃度が１０ｍａｓｓｐｐｍ以下 であることがより好ましい。また、Ｓ濃度の下限値は特に限定されないが、０を含まない値で（又は０を超える値）あってよい。
　また、アトマイズ処理など、有限の圧力下で実施される工程において、大気中もしくは工程中に含まれる雰囲気成分が原因となり、粉末に雰囲気成分が含まれることが生じ得る。例えば、粉末に雰囲気成分に由来する窒素が含まれることが生じ得る。本実施形態である金属ＡＭ用銅合金粉末においては、窒素濃度（Ｎ濃度）が、３０ｍａｓｓｐｐｍであることが望ましく、２０ｍａｓｓｐｐｍであることがより望ましく、１０ｍａｓｓｐｐｍ以下であることが更に望ましい。また、本実施形態である金属ＡＭ用銅合金粉末においては、窒素濃度（Ｎ濃度）が５ｍａｓｓｐｐｍ以下であることがさらに望ましい。また、Ｎ濃度の下限値は特に限定されないが、０を含まない値で（又は０を超える値）あってよい。 The copper alloy powder for metal AM according to the present embodiment is manufactured by the above-mentioned steps. In the copper alloy powder for metal AM according to the present embodiment, the O concentration is preferably 1000 mass ppm or less, the H concentration is preferably 5 mass ppm or less, and the S concentration is preferably 10 mass ppm or less.
Specifically, the O concentration may be about 2700 ppm by mass or less, preferably 1000 ppm by mass or less, and more preferably 900 ppm by mass or less. The lower limit of the O concentration is not particularly limited, but may be a value that does not include 0 (or a value that exceeds 0).
If the O concentration is high, foreign matter in the form of oxygen or oxides may remain in the molded body, which may deteriorate various characteristics of the molded body.
The H concentration may be 90 mass ppm or less, may be 60 mass ppm or less, and is preferably 5 mass ppm or less. The lower limit of the H concentration is not particularly limited, but may be a value that does not include 0 (or a value that exceeds 0).
The S concentration may be 90 mass ppm or less, may be 60 mass ppm or less, and is preferably 30 mass ppm or less. Furthermore, the S concentration in the copper alloy powder for metal AM is more preferably 10 mass ppm or less. The lower limit of the S concentration is not particularly limited, but may be a value that does not include 0 (or a value that exceeds 0).
In addition, in a process carried out under a finite pressure, such as an atomization process, atmospheric components contained in the atmosphere or during the process may cause the powder to contain atmospheric components. For example, nitrogen derived from atmospheric components may be contained in the powder. In the copper alloy powder for metal AM of this embodiment, the nitrogen concentration (N concentration) is preferably 30 mass ppm, more preferably 20 mass ppm, and even more preferably 10 mass ppm or less. In the copper alloy powder for metal AM of this embodiment, the nitrogen concentration (N concentration) is more preferably 5 mass ppm or less. In addition, the lower limit of the N concentration is not particularly limited, but may be a value that does not include 0 (or a value that exceeds 0).
　なお、金属ＡＭ用銅合金粉末は、合金元素以外の添加元素および不純物元素は、特性に影響を与えない範囲で含有されていてもよい。
　ここで、合金元素以外の添加元素および不純物元素（Ｏ，Ｈ，Ｓ，及びＮを除く）は、総量で０．０７ｍａｓｓ％以下であってもよく、０．０６ｍａｓｓ％以下であってもよく、０．０５ｍａｓｓ％以下であってもよく、０．０４ｍａｓｓ％以下とすることが好ましく、０．０３ｍａｓｓ％以下とすることがさらに好ましく、０．０２ｍａｓｓ％以下とすることがより好ましく、さらには０．０１ｍａｓｓ％以下とすることが好ましい。
　また、合金元素以外の添加元素および不純物元素（Ｏ，Ｈ，Ｓ，及びＮを除く）のそれぞれの含有量の上限は、３０ｍａｓｓｐｐｍ以下とすることが好ましく、２０ｍａｓｓｐｐｍ以下とすることがさらに好ましく、１５ｍａｓｓｐｐｍ以下とすることがより好ましい。 The copper alloy powder for metal AM may contain additive elements and impurity elements other than the alloy elements to the extent that they do not affect the characteristics.
Here, the total amount of additive elements other than alloy elements and impurity elements (excluding O, H, S, and N) may be 0.07 mass% or less, may be 0.06 mass% or less, may be 0.05 mass% or less, is preferably 0.04 mass% or less, is more preferably 0.03 mass% or less, is further preferably 0.02 mass% or less, and is further preferably 0.01 mass% or less.
In addition, the upper limit of the content of each of additive elements other than alloy elements and impurity elements (excluding O, H, S, and N) is preferably 30 mass ppm or less, more preferably 20 mass ppm or less, and even more preferably 15 mass ppm or less.
　次に、本実施形態である積層造形物の製造方法について、図４のフロー図を用いて説明する。
　本実施形態である積層造形物の製造方法は、上述の金属ＡＭ用銅合金粉末を準備する準備工程Ｓ１０１と、金属ＡＭ用銅合金粉末を含む粉末層を形成する第１工程Ｓ１２１と粉末層において所定位置の前記金属ＡＭ用銅合金粉末を固化させて造形層を形成する第２工程Ｓ１２２とを順次繰り返して積層造形物を作製する造形工程Ｓ１０２と、を備えている。
　このような工程により、所定の形状の積層造形物が製造される。この積層造形物においては、本実施形態である金属ＡＭ用銅合金粉末を用いていることから、ボイドなどの構造欠陥が少なく、機械的特性に優れている。 Next, the method for producing a layered object according to the present embodiment will be described with reference to the flow chart of FIG.
The manufacturing method of an additively molded object in this embodiment includes a preparation process S101 for preparing the above-mentioned copper alloy powder for metal AM, a first process S121 for forming a powder layer containing the copper alloy powder for metal AM, and a second process S122 for solidifying the copper alloy powder for metal AM at a predetermined position in the powder layer to form a molding layer, and a modeling process S102 for producing an additively molded object by sequentially repeating these steps.
By these steps, a layered object having a predetermined shape is manufactured. Since the layered object uses the copper alloy powder for metal AM according to the present embodiment, the layered object has few structural defects such as voids and has excellent mechanical properties.
　以上のような構成とされた本実施形態である金属ＡＭ用銅合金粉末は、Ｓｉを含有する銅合金粒子５０で構成され、金属ＡＭ用銅合金粉末を構成する銅合金粒子５０の表面にはＳｉが偏析しており、粒子本体５１の外表面にＳｉ濃化層５２が形成されているので、積層造形により作製した造形体の微細構造の再現性が高く、ボイド等の構造欠陥が少ない高品質な積層造形物を安定して製造することが可能となる。 The copper alloy powder for metal AM of this embodiment configured as described above is composed of copper alloy particles 50 containing Si, and Si is segregated on the surface of the copper alloy particles 50 that constitute the copper alloy powder for metal AM, and a Si-enriched layer 52 is formed on the outer surface of the particle body 51. This makes it possible to stably manufacture high-quality additively manufactured objects with high reproducibility of the microstructure of the object produced by additive manufacturing and with few structural defects such as voids.
　ここで、本実施形態である金属ＡＭ用銅合金粉末において、粒子本体５１の表面に形成されたＳｉ濃化層５２がＳｉとＯを含む酸化層とされている場合には、金属ＡＭ用銅合金粉末の変質を抑制することができ、積層造形により作製した造形体の微細構造の再現性が高く、ボイド等の構造欠陥が少ないさらに高品質な積層造形物をさらに安定して製造することが可能となる。 Here, in the copper alloy powder for metal AM of this embodiment, when the Si-enriched layer 52 formed on the surface of the particle body 51 is an oxide layer containing Si and O, it is possible to suppress the deterioration of the copper alloy powder for metal AM, and it is possible to more stably manufacture an even higher quality additively manufactured object with high reproducibility of the microstructure of the object produced by additive manufacturing and with fewer structural defects such as voids.
　また、本実施形態である金属ＡＭ用銅合金粉末において、銅合金粒子５０を構成する銅合金が、Ｃｒを０．１質量％以上０．８質量％以下の範囲内、Ｓｉを０．４質量％以上０．８質量％以下の範囲内、Ｎｉを１．８質量％以上３．０質量％以下の範囲内で含み、その他が銅及び不純物からなる組成とされている場合には、この金属ＡＭ用銅合金粉末を用いて作製された積層造形物に対して適切な熱処理を施すことにより、化合物を析出させることができ、導電性、熱伝導性、強度に優れた積層造形物を製造することが可能となる。 In addition, in the copper alloy powder for metal AM of this embodiment, when the copper alloy constituting the copper alloy particles 50 contains Cr in the range of 0.1 mass% to 0.8 mass%, Si in the range of 0.4 mass% to 0.8 mass%, Ni in the range of 1.8 mass% to 3.0 mass%, and the rest is copper and impurities, by subjecting an additive manufacturing product made using this copper alloy powder for metal AM to an appropriate heat treatment, compounds can be precipitated, making it possible to manufacture an additive manufacturing product with excellent electrical conductivity, thermal conductivity, and strength.
　また、本実施形態である金属ＡＭ用銅合金粉末において、レーザー回折・散乱法にて測定された体積基準の５０％累積粒子径Ｄ５０が５μｍ以上１２０μｍ以下の範囲内とされている場合には、金属ＡＭに適した粒度分布を有しており、積層造形物を安定して製造することが可能となる。 In addition, in the copper alloy powder for metal AM of this embodiment, when the 50% cumulative particle diameter D50 on a volume basis measured by the laser diffraction/scattering method is within the range of 5 μm or more and 120 μm or less, it has a particle size distribution suitable for metal AM, and it becomes possible to stably manufacture additive manufacturing objects.
　また、本実施形態である金属ＡＭ用銅合金粉末において、レーザー回折・散乱法にて測定された体積基準の１０％累積粒子径Ｄ１０が１μｍ以上８０μｍ以下の範囲内とされている場合には、金属ＡＭに適した粒度分布を有しており、積層造形物を安定して製造することが可能となる。 In addition, in the copper alloy powder for metal AM of this embodiment, when the volume-based 10% cumulative particle diameter D10 measured by the laser diffraction/scattering method is within the range of 1 μm or more and 80 μm or less, it has a particle size distribution suitable for metal AM, and it becomes possible to stably manufacture additive manufacturing objects.
　また、本実施形態である金属ＡＭ用銅合金粉末において、レーザー回折・散乱法にて測定された体積基準の９０％累積粒子径Ｄ９０が１０μｍ以上１５０μｍ以下の範囲内とされている場合には、金属ＡＭに適した粒度分布を有しており、積層造形物を安定して製造することが可能となる。 In addition, in the copper alloy powder for metal AM of this embodiment, when the volume-based 90% cumulative particle diameter D90 measured by the laser diffraction/scattering method is within the range of 10 μm or more and 150 μm or less, it has a particle size distribution suitable for metal AM, and it becomes possible to stably manufacture additive manufacturing objects.
　本実施形態である積層造形物の製造方法においては、本実施形態である金属ＡＭ用銅合金粉末を用いているので、積層造形により作製した造形物の微細構造の再現性が高く、ボイド等の構造欠陥が少ない高品質な積層造形物を安定して製造することが可能となる。 The manufacturing method for additive manufacturing of this embodiment uses the copper alloy powder for metal AM of this embodiment, which makes it possible to reproducibly produce the microstructure of the object produced by additive manufacturing, and to stably manufacture high-quality additive manufacturing objects with few structural defects such as voids.
　以上、本発明の実施形態である金属ＡＭ用銅合金粉末、および、積層造形物の製造方法について説明したが、本発明はこれに限定されることはなく、その発明の技術的思想を逸脱しない範囲で適宜変更可能である。
　例えば、上述の実施形態では、ガスアトマイズ法によって金属ＡＭ用銅合金粉末を製造するものとして説明したが、これに限定されることはなく、水アトマイズ法、遠心力アトマイズ法、プラズマアトマイズ法などによって、金属ＡＭ用銅合金粉末を製造してもよい。 The copper alloy powder for metal AM and the method for manufacturing an additive manufacturing object according to the embodiment of the present invention have been described above. However, the present invention is not limited thereto and can be modified as appropriate without departing from the technical concept of the invention.
For example, in the above-described embodiment, the copper alloy powder for metal AM is produced by gas atomization, but this is not limited thereto, and the copper alloy powder for metal AM may be produced by water atomization, centrifugal atomization, plasma atomization, or the like.
　また、上述のように得られた金属ＡＭ用銅合金粉末に対し、雰囲気を制御して適宜熱処理を施して組織の安定化などを図ってもよい。
　さらに、本実施形態では、レーザーＰＢＦ法に適した金属ＡＭ用銅合金粉末を製造するものとして説明したが、これに限定されることはなく、その他の積層造形法に適用する金属ＡＭ用銅合金粉末であってもよい。 The copper alloy powder for metal AM obtained as described above may be appropriately heat-treated in a controlled atmosphere to stabilize the structure.
Furthermore, in this embodiment, the copper alloy powder for metal AM suitable for the laser PBF method has been described as being produced, but this is not limited to this, and the copper alloy powder for metal AM applicable to other additive manufacturing methods may also be used.
　さらに、造形工程Ｓ１０２の後に、３００℃以上純銅の融点以下の温度で熱処理する熱処理工程を実施してもよい。また、造形工程Ｓ１０２の後に、８００℃以上純銅の融点以下の温度範囲で熱処理する第一熱処理工程と、この第一熱処理工程の後に、３００℃以上８００℃以下の温度範囲で熱処理を行う第二熱処理工程を実施してもよい。
　また、本実施形態では、図３に示す連続鋳造装置を用いて銅合金鋳塊を製造するものとして説明したが、これに限定されることはなく、その他の鋳造装置を用いてもよい。 Furthermore, after the shaping process S102, a heat treatment process may be performed in which heat treatment is performed at a temperature of 300° C. or more and the melting point of pure copper or less. Also, after the shaping process S102, a first heat treatment process may be performed in which heat treatment is performed at a temperature range of 800° C. or more and the melting point of pure copper or less, and after this first heat treatment process, a second heat treatment process may be performed in which heat treatment is performed at a temperature range of 300° C. or more and 800° C. or less.
In addition, in the present embodiment, the continuous casting apparatus shown in FIG. 3 is used to produce a copper alloy ingot, but the present invention is not limited to this, and other casting apparatuses may be used.
　例えば、図５に示す連続鋳造装置１０１を用いてもよい。この連続鋳造装置１０１は、最上流部に配置された無酸素銅供給手段（銅溶湯供給部）１０２と、その下流に配置された加熱炉１０３と、加熱炉１０３の下流に配置されて銅溶湯が供給されるタンディシュ１０４と、無酸素供給手段１０２から加熱炉１０３までをつなぐ溶湯供給路１０５ａ，１０５ｂ，１０５ｃと、加熱炉１０３とタンディシュ１０４とをつなぐ樋１０６と、非酸化性雰囲気で合金元素を添加する添加手段（添加部）１０７，１０８と、連続鋳造鋳型１４２と、を備えている。なお、無酸素銅供給手段１０２、加熱炉１０３、タンディッシュ１０４、溶湯供給路１０５ａ，１０５ｂ，１０５ｃおよび樋１０６は、それぞれの内部を非酸化性雰囲気としている。 For example, a continuous casting device 101 shown in FIG. 5 may be used. This continuous casting device 101 includes an oxygen-free copper supply means (molten copper supply section) 102 arranged at the most upstream portion, a heating furnace 103 arranged downstream thereof, a tundish 104 arranged downstream of the heating furnace 103 and supplied with molten copper, molten metal supply passages 105a, 105b, and 105c connecting the oxygen-free supply means 102 to the heating furnace 103, a trough 106 connecting the heating furnace 103 and the tundish 104, addition means (addition sections) 107 and 108 for adding alloy elements in a non-oxidizing atmosphere, and a continuous casting mold 142. The oxygen-free copper supply means 102, the heating furnace 103, the tundish 104, the molten metal supply passages 105a, 105b, and 105c, and the trough 106 each have a non-oxidizing atmosphere inside.
　無酸素銅供給手段１０２は、銅原料を溶解する溶解炉１２１と、溶解炉１２１で溶解されて得られた溶銅を一時保持する保持炉１２２と、溶銅中の酸素および水素を除去する脱ガス処理装置１２４と、これらをつなぐ溶湯供給路１０５ａ，１０５ｂ，１０５ｃと、で構成されている。 The oxygen-free copper supply means 102 is composed of a melting furnace 121 for melting the copper raw material, a holding furnace 122 for temporarily holding the molten copper obtained by melting in the melting furnace 121, a degassing treatment device 124 for removing oxygen and hydrogen from the molten copper, and molten metal supply paths 105a, 105b, and 105c that connect these.
　脱ガス処理装置１２４は、その内部で溶銅が攪拌されるように攪拌手段としてガスバブリング装置を有しており、例えば不活性ガスによるバブリング等を行うことにより、溶銅から酸素および水素を除去する。
　溶湯供給路１０５ａ、１０５ｂ、１０５ｃは、溶銅および無酸素銅溶湯が酸化されるのを防止するために、その内部を非酸化性雰囲気としている。この非酸化性雰囲気は、例えば、窒素と一酸化炭素の混合ガスやアルゴン等の不活性ガスを溶湯供給路内に吹き込むことにより形成される。 The degassing treatment device 124 has a gas bubbling device as stirring means for stirring the molten copper therein, and removes oxygen and hydrogen from the molten copper by bubbling with an inert gas, for example.
The molten metal supply passages 105a, 105b, and 105c have a non-oxidizing atmosphere therein to prevent the molten copper and the oxygen-free copper molten metal from being oxidized. The non-oxidizing atmosphere is formed by blowing a mixed gas of nitrogen and carbon monoxide or an inert gas such as argon into the molten metal supply passages.
　合金元素を添加する添加手段として、加熱炉１０３に配設された第１の添加手段１０７と、タンディシュ１０４に配設された第２の添加手段１０８と、を備えている。
　加熱炉１０３に設けられた第１の添加手段１０７から合金元素を連続的にまたは間欠的に装入すると、加熱炉１０３内に貯留された無酸素銅溶湯中に合金元素が添加される。ここで、貯留部に貯留された無酸素銅溶湯は、高周波誘導コイルによって加熱され、添加された合金元素の溶解が促進されることになる。
　また、タンディシュ１０４に設けられた第２の添加手段１０８から合金元素を連続的にまたは間欠的に装入すると、タンディシュ１０４内を流れる無酸素銅溶湯中に合金元素が添加される。ここで、タンディッシュ１０４内を流れる無酸素銅溶湯は、加熱炉１０３で加熱されて高温であるとともにタンディッシュ１０４内を流動していることから、添加された合金元素の溶解が促進されることになる。 As adding means for adding alloy elements, a first adding means 107 disposed in the heating furnace 103 and a second adding means 108 disposed in the tundish 104 are provided.
When alloying elements are continuously or intermittently charged from a first adding means 107 provided in the heating furnace 103, the alloying elements are added to the oxygen-free copper molten metal stored in the heating furnace 103. Here, the oxygen-free copper molten metal stored in the storage section is heated by a high-frequency induction coil, and the melting of the added alloying elements is promoted.
Furthermore, when alloying elements are continuously or intermittently charged from the second adding means 108 provided in the tundish 104, the alloying elements are added to the molten oxygen-free copper flowing in the tundish 104. Here, since the molten oxygen-free copper flowing in the tundish 104 is heated in the heating furnace 103 and has a high temperature, and also flows within the tundish 104, the dissolution of the added alloying elements is promoted.
　以下に、本発明の効果を確認すべく行った確認実験の結果について説明する。 Below, we explain the results of the confirmation experiments conducted to confirm the effectiveness of the present invention.
（本発明例）
　まず、実施形態に記載した製造方法により、４Ｎグレードの高純度銅からなる銅原料を用いて、表１に示す組成のＣ１８０００の鋳塊を作製した。
　次に、作製したＣ１８０００の鋳塊を原料として、アルゴンガスを用いるガスアトマイズ法によって、表２に示す組成の金属ＡＭ用銅合金粉末を作製し、金属ＡＭの粉末床に適する粒度に分級した。ガスアトマイズ処理時の溶解温度は１４００℃の条件で行った。
　本発明例の金属ＡＭ用銅合金粉末について、マイクロトラック社製ＭＴ３３００ＥＸIIを用いた粒径分布測定を行った結果、体積基準の１０％累積粒子径が１５μｍ、５０％累積粒子径が２４μｍ、９０％累積粒子径が３８μｍの粒度分布となった。本発明例の金属ＡＭ用銅合金粉末では、後述する通り、銅合金粒子の表面にはＳｉ濃化層が観察された。
　そして、本発明例の金属ＡＭ用Ｃ１８０００粉末を用い、市販のレーザーＰＢＦ装置を用いてエネルギー密度を１３Ｊ／ｍｍ２の条件で、積層造形物の小片を作製した。 (Example of the invention)
First, by the manufacturing method described in the embodiment, a copper raw material made of 4N grade high purity copper was used to produce an ingot of C18000 having the composition shown in Table 1.
Next, the produced C18000 ingot was used as a raw material to produce copper alloy powder for metal AM having the composition shown in Table 2 by gas atomization using argon gas, and the powder was classified to a particle size suitable for the powder bed of metal AM. The melting temperature during the gas atomization process was 1400°C.
The particle size distribution of the copper alloy powder for metal AM of the present invention was measured using MT3300EXII manufactured by Microtrac Co., Ltd., and the particle size distribution was as follows: 10% cumulative particle size on a volume basis was 15 μm, 50% cumulative particle size was 24 μm, and 90% cumulative particle size was 38 μm. In the copper alloy powder for metal AM of the present invention, a Si-enriched layer was observed on the surface of the copper alloy particles, as described later.
Then, using the C18000 powder for metal AM of the present invention, a small piece of an additive manufacturing object was produced using a commercially available laser PBF device at an energy density of 13 J/ mm2 .
（比較例）
　比較例として、本発明例とは異なり、粒子表面にＳｉ濃化層が形成されていないＣ１８０００の組成を有する金属ＡＭ用銅合金粉末を準備した。
　比較例の金属ＡＭ用銅合金粉末について、マイクロトラック社製ＭＴ３３００ＥＸIIを用いた粒径分布測定を行った結果、体積基準の１０％累積粒子径が１６μｍ、５０％累積粒子径が２８μｍ、９０％累積粒子径が４５μｍの粒度分布となった。
　そして、比較例のＣ１８０００の組成を有する金属ＡＭ用銅合金粉末と、市販のレーザーＰＢＦ装置を用いて、積層厚みを含め、本発明例と同じ造形条件にて積層造形物の小片を作製した。 Comparative Example
As a comparative example, a copper alloy powder for metal AM having the composition of C18000, which does not have a Si-enriched layer formed on the particle surface, unlike the examples of the present invention, was prepared.
For the comparative copper alloy powder for metal AM, particle size distribution measurement was performed using MT3300EXII manufactured by Microtrac, and the particle size distribution was as follows: 10% cumulative particle size on a volume basis was 16 μm, 50% cumulative particle size was 28 μm, and 90% cumulative particle size was 45 μm.
Then, using a copper alloy powder for metal AM having the composition of C18000 of the comparative example and a commercially available laser PBF device, a small piece of an additively molded object was produced under the same molding conditions as the example of the present invention, including the layer thickness.
（金属ＡＭ用銅合金粉末の表面構造）
　本発明例および比較例の金属ＡＭ用銅合金粉末の粒子の微細構造を、オージェ電子分光分析法を用いて評価した。結果を図６Ａ及び図６Ｂ，並びに図７Ａ及び図７Ｂに示す。なお、図７Ａ及び図７Ｂにおいて、実線が本発明例の金属ＡＭ用銅合金粉末の分析結果であり、点線が比較例の金属ＡＭ用銅合金粉末の分析結果である。 (Surface structure of copper alloy powder for metal AM)
The particle microstructures of the copper alloy powders for metal AM of the present invention and the comparative example were evaluated using Auger electron spectroscopy. The results are shown in Figures 6A and 6B, and Figures 7A and 7B. In Figures 7A and 7B, the solid line shows the analysis result of the copper alloy powder for metal AM of the present invention, and the dotted line shows the analysis result of the copper alloy powder for metal AM of the comparative example.
（Ｓｉ濃化層の有無）
　本発明例および比較例の金属ＡＭ用銅合金粉末について、アルバック・ファイ株式会社製走査型オージェ電子分光分析装置ＰＨＩ７００xiを用い、分析目的の粒子本体について、表面のオージェ電子信号計測開始から３０秒毎に、計測時間(t)に伴うＳｉ元素の信号強度（IAES(t)）を測定した。
　そして、このIAES(t)の一つに対して、Ｓｉ元素に関するIAES(t)が概ね一定になる領域を６点以上確認し、これらのIAES(t)が一定となる領域において、IAES(t)の平均値を算出した。この平均値を平均バックグラウンド強度（IAES,BG AVE）と定義した。次に、取得した全てのtにおけるIAES(t)をIAES,BG AVEで除した数値を求めた。この数値をIAES, NORM(t)と定義した。IAES, NORM(t)は以下の式（１）により表した。
　IAES, NORM(t) ＝ IAES(t) / IAES,BG AVE　　　式（１） (Presence or absence of Si-enriched layer)
For the copper alloy powders for metal AM of the present invention and the comparative examples, a scanning Auger electron spectrometer PHI700xi manufactured by ULVAC-PHI, Inc. was used to measure the signal intensity ( IAES (t)) of the Si element over the measurement time (t) for the particle body to be analyzed every 30 seconds from the start of measurement of the Auger electron signal on the surface.
Then, for one of these I AES (t), six or more regions where the I AES (t) for the Si element was roughly constant were identified, and the average value of I AES (t) was calculated in these regions where the I AES (t) was constant. This average value was defined as the average background intensity (I AES , BG AVE ). Next, the I AES (t) at all the acquired ts was divided by I AES , BG AVE to obtain a numerical value. This numerical value was defined as I AES, NORM (t). I AES, NORM (t) was expressed by the following formula (1).
I AES, NORM (t) = I AES (t) / I AES , BG AVE Equation (1)
　t- IAES,NORM(t)関係において、Ｓｉ濃化層では計測時間の低下と共にIAES,NORM(t)が連続的に増大していた。このIAES,NORM(t)の連続的な増加が観測される領域の開始時間をＳｉ濃化層の末端となる時間ts0と定義した。
　本発明例では、ts0は約２ｍｉｎであった。また、IAES, NORM(t)を、Ｓｉ強度倍率因子(Si intensity amplification factor）とした。
　以上の測定及び計算で得た、本発明例の金属ＡＭ用銅合金粉末の、計測時間(t)、Ｓｉ元素の信号強度（IAES(t)）、Ｓｉ強度倍率因子IAES, NORM(t)を表５に示した。なお、本発明例において平均バックグラウンド強度（IAES,BG AVE）は、２８４７．５７であった。
　表５では、Ｓｉ濃化層が存在する本発明例では、Ｓｉ強度倍率因子が２を超える数値が明確に観測され、Ｓｉ信号強度がバックグラウンド強度に対して明らかに強くなる状況が確認された。従って、本発明例の金属ＡＭ用銅合金粉末の粒子本体にはＳｉ濃化層が存在すると確認された。
　一方、比較例では、Ｓｉ強度倍率因子が２を超える数値が観測されず、金属ＡＭ用銅合金粉末の粒子本体にはＳｉ濃化層が存在しなかったと考えられた。 In the t- I AES,NORM (t) relationship, I AES,NORM (t) increased continuously with decreasing measurement time in the Si-enriched layer. The start time of the region where this continuous increase in I AES,NORM (t) was observed was defined as t s0 , which is the end of the Si-enriched layer.
In the present invention, t s0 was about 2 min, and I AES, NORM (t) was taken as the Si intensity amplification factor.
The measurement time (t), signal intensity of Si element (I AES (t)), and Si intensity magnification factor I AES, NORM (t) of the copper alloy powder for metal AM of the present invention obtained by the above measurements and calculations are shown in Table 5. The average background intensity (I AES , BG AVE ) of the present invention example was 2847.57.
In Table 5, in the present invention examples in which a Si-enriched layer exists, a Si intensity magnification factor exceeding 2 was clearly observed, and it was confirmed that the Si signal intensity was clearly stronger than the background intensity. Therefore, it was confirmed that a Si-enriched layer exists in the particle body of the copper alloy powder for metal AM of the present invention example.
On the other hand, in the comparative examples, no Si strength magnification factor exceeding 2 was observed, and it was considered that no Si-enriched layer was present in the particle body of the copper alloy powder for metal AM.
（鋳塊および金属ＡＭ用銅合金粉末の組成）
　表１に示す鋳塊、および、本発明例の金属ＡＭ用銅合金粉末、比較例の金属ＡＭ用銅合金粉末におけるＯ濃度は不活性ガス融解―赤外線吸収法、Ｈ濃度は不活性ガス融解―熱伝導度法、Ｓ濃度は燃焼―赤外線吸収法で求めた。また、銅を除き、これらの物質以外の成分の濃度は、蛍光Ｘ線分析法、グロー放電質量分析法、誘導結合プラズマ質量分析法を組み合わせて求めた。評価結果を表１，２に示す。 (Composition of ingot and copper alloy powder for metal AM)
The O concentration in the ingots shown in Table 1, the copper alloy powders for metal AM of the present invention, and the copper alloy powders for metal AM of the comparative examples was determined by inert gas fusion-infrared absorption method, the H concentration by inert gas fusion-thermal conductivity method, and the S concentration by combustion-infrared absorption method. The concentrations of components other than these substances, except for copper, were determined by a combination of X-ray fluorescence analysis, glow discharge mass spectrometry, and inductively coupled plasma mass spectrometry. The evaluation results are shown in Tables 1 and 2.
（造形物密度）
　作製した積層造形物の断面と、積層造形物の断面において観測されるボイドが占有する面積から、積層造形物の密度を評価した。本明細書においては、この密度を造形物密度と定義する。
　造形物密度の評価は、造形物断面において計測対象の断面積を定義した後（これを評価断面積と呼ぶ。３．４ｍｍ四方。）、この計測断面積の内部にあるボイド箇所を確認した後、評価断面積におけるボイドの占有面積を算出した。そして、（評価断面積－ボイド占有面積）／評価断面積を造形物密度と定義した。造形物密度の評価結果を表３に示す。 (Object density)
The density of the layered object was evaluated from the cross section of the layered object and the area occupied by voids observed in the cross section of the layered object. In this specification, this density is defined as the density of the object.
The density of the molded object was evaluated by first defining the cross-sectional area of the object to be measured (this is called the evaluation cross-sectional area; 3.4 mm square), and then checking for voids within this measurement cross-sectional area, and calculating the area occupied by voids in the evaluation cross-sectional area. The density of the molded object was then defined as (evaluation cross-sectional area - void-occupied area)/evaluation cross-sectional area. The evaluation results of the density of the molded object are shown in Table 3.
（造形物の機械的特性および電気伝導度の評価）
　作製した積層造形物の機械的特性として、室温においてビッカース硬度（ＨＶ単位）をＪＩＳＺ２２４４：２００９に準じて測定した。ビッカース硬度の測定荷重は１０ｋｇｆとした。また、作製した積層造形物の％ＩＡＣＳ単位の導電率を過流式導電率測定により室温において計測した。評価結果を表４に示す。 (Evaluation of mechanical properties and electrical conductivity of the object)
As a mechanical property of the produced laminated object, the Vickers hardness (HV unit) was measured at room temperature according to JIS Z2244:2009. The load for measuring the Vickers hardness was 10 kgf. The electrical conductivity of the produced laminated object in %IACS units was measured at room temperature by eddy current electrical conductivity measurement. The evaluation results are shown in Table 4.
Figure JPOXMLDOC01-appb-T000001
 　（表１で示す不純物は不純物からＯ，Ｈ，Ｓを除く。）
Figure JPOXMLDOC01-appb-T000001
 (The impurities shown in Table 1 exclude O, H, and S.)
Figure JPOXMLDOC01-appb-T000002
 　（表２で示す不純物は不純物からＯ，Ｈ，Ｓ，Ｎを除く。）
Figure JPOXMLDOC01-appb-T000002
 (The impurities shown in Table 2 exclude O, H, S, and N.)
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000005
　図６Ａ及び図６Ｂは、本発明例の金属ＡＭ用銅合金粉末の粒子表面のオージェ電子分光分析の結果を示す。図６Ａ及び図６Ｂに示すように、本発明例の金属ＡＭ用銅合金粉末の銅合金粒子の表面（或いは表層）にはＳｉ濃化層が存在し、粒子表面が全体的にＳｉ濃化層で覆われていることが確認された。 Figures 6A and 6B show the results of Auger electron spectroscopy analysis of the particle surface of the copper alloy powder for metal AM of the present invention. As shown in Figures 6A and 6B, it was confirmed that a Si-enriched layer exists on the surface (or surface layer) of the copper alloy particles of the copper alloy powder for metal AM of the present invention, and that the particle surface is entirely covered with the Si-enriched layer.
　さらに、図７Ａ及び図７Ｂは、本発明の金属ＡＭ用銅合金粉末の粒子表面のオージェ電子分光分析により得られたＳｉ及びＯの強度デプスプロファイルを示す。本オージェ電子分光分析の実験系における本発明例の銅合金粉末の粒子表面における各構成元素単体や各構成元素により生じる化合物のエッチングレートは定かではないが、本オージェ電子分光分析の実験系におけるＳｉＯ２のエッチングレートは１．０８ｎｍ／分であることから、７分間のイオンエッチングは概ね１０ｎｍの厚みをエッチングした後の構造であると考えられる。 7A and 7B show the intensity depth profiles of Si and O obtained by Auger electron spectroscopy of the particle surface of the copper alloy powder for metal AM of the present invention. The etching rate of each element alone or compounds generated by each element on the particle surface of the copper alloy powder of the present invention example in the experimental system of this Auger electron spectroscopy is not clear, but since the etching rate of SiO2 in the experimental system of this Auger electron spectroscopy is 1.08 nm/min, it is considered that the structure after ion etching for 7 minutes is approximately 10 nm thick.
　図７Ｂに示すように、本発明例の金属ＡＭ用銅合金粉末においては、粉末の表面側のＳｉ濃度が高く、粉末の表面にＳｉ濃化層が形成されていることが確認された。この結果から、Ｓｉ濃化層の厚みは、概ね１ｎｍから１００ｎｍ程度の範囲になると考えられる。一方、図７Ｂに示すように、比較例の金属ＡＭ用銅合金粉末においては、粉末の表面にＳｉは偏析しておらず、粉末の表面にＳｉ濃化層は形成されていないと認められる。 As shown in Figure 7B, in the copper alloy powder for metal AM of the present invention, the Si concentration is high on the surface side of the powder, and it was confirmed that a Si-enriched layer was formed on the surface of the powder. From this result, it is considered that the thickness of the Si-enriched layer is generally in the range of about 1 nm to 100 nm. On the other hand, as shown in Figure 7B, in the copper alloy powder for metal AM of the comparative example, Si does not segregate on the surface of the powder, and it is recognized that a Si-enriched layer is not formed on the surface of the powder.
　また、図７Ａに示すように、本発明例の金属ＡＭ用銅合金粉末においては、粉末の表面側のＯ濃度が高く、粉末の表面に形成されたＳｉ濃化層が酸素（Ｏ）を含有していることが確認された。すなわち、本発明例の金属ＡＭ用銅合金粉末におけるＳｉ濃化層は、ＳｉとＯを含む層で構成されていると考えられる。このように、本発明例の金属ＡＭ用銅合金粉末においては、Ｓｉ濃化層において酸素も同時に検出され、銅合金粉末の表面変質を比較的抑制できると考えられる。
　本質的に、本発明の金属ＡＭ用銅合金粉末は、銅合金としての酸素を含むため、粒子本体には一定量の酸素が存在し、これが粒子本体の酸素濃度のバックグラウンド濃度を構成するものと考えられる。一方、粒子表面においては、主として粉末化の工程によって、上記のＳｉ濃化層の厚みのオーダーにおいて酸素濃度の勾配が生じ得ると考えられる。   7A, it was confirmed that the O concentration on the surface side of the copper alloy powder for metal AM of the present invention is high, and the Si-enriched layer formed on the surface of the powder contains oxygen (O). That is, it is considered that the Si-enriched layer in the copper alloy powder for metal AM of the present invention is composed of a layer containing Si and O. Thus, it is considered that oxygen is also detected at the same time in the Si-enriched layer in the copper alloy powder for metal AM of the present invention, and surface deterioration of the copper alloy powder can be relatively suppressed.
Essentially, the copper alloy powder for metal AM of the present invention contains oxygen as a copper alloy, so that a certain amount of oxygen exists in the particle body, which is considered to constitute the background concentration of oxygen in the particle body. On the other hand, it is considered that a gradient of oxygen concentration can be generated on the particle surface, mainly due to the powdering process, on the order of the thickness of the above-mentioned Si-enriched layer.
　そして、表３に示すように、粒子表面にＳｉが濃化したＳｉ濃化層が形成された本発明例の金属ＡＭ用銅合金粉末を用いて造形した場合、造形物密度は９９．６％となった。
　一方、Ｓｉ濃化層が形成されていない金属ＡＭ用銅合金粉末を用いて造形した場合、比較例に示すように、充填密度は９９％となった。
　これらの結果から、本発明例のＳｉ濃化層を有する金属ＡＭ用銅合金粉末においては、実使用に重要となるボイドの発生を顕著に抑制された高品位な積層造形物を製造可能であることが確認された。
　また、表４に示すように、本発明の積層造形物を、表４に示す条件で熱処理を施すことにより、実用性の高い特性を有する銅合金造形体を提供できることを確認した。 As shown in Table 3, when molding was performed using the copper alloy powder for metal AM of the present invention in which a Si-enriched layer was formed on the particle surface, the density of the molded object was 99.6%.
On the other hand, when molding was performed using a copper alloy powder for metal AM in which no Si-enriched layer was formed, the packing density was 99%, as shown in the comparative example.
From these results, it was confirmed that the copper alloy powder for metal AM having a Si-enriched layer of the present invention can produce high-quality additive manufacturing objects in which the occurrence of voids, which is important for practical use, is significantly suppressed.
Furthermore, as shown in Table 4, it was confirmed that by subjecting the layered object of the present invention to a heat treatment under the conditions shown in Table 4, a copper alloy shaped body having highly practical properties can be provided.
　５０　金属ＡＭ用銅合金粉末を構成する銅合金粒子
　５１　粒子本体
　５２　Ｓｉ濃化層 50 Copper alloy particle constituting copper alloy powder for metal AM 51 Particle body 52 Si-enriched layer

Claims (10)

  1. 　金属ＡＭに用いられる金属ＡＭ用銅合金粉末であって、
    　Ｓｉを含有する銅合金からなり、
    　粉末を構成する銅合金粒子の表面にＳｉ濃化層が連続的に形成されていることを特徴とする金属ＡＭ用銅合金粉末。     A copper alloy powder for metal AM used in metal AM,
    Made of a copper alloy containing Si,
    A copper alloy powder for metal AM, characterized in that a Si-enriched layer is continuously formed on the surface of the copper alloy particles constituting the powder.
  2. 　前記銅合金はＣｒを含有していることを特徴とする請求項１に記載の金属ＡＭ用銅合金粉末。 The copper alloy powder for metal AM described in claim 1, characterized in that the copper alloy contains Cr.
  3. 　前記Ｓｉ濃化層が酸素を含有していることを特徴とする請求項１に記載の金属ＡＭ用銅合金粉末。 The copper alloy powder for metal AM described in claim 1, characterized in that the Si-enriched layer contains oxygen.
  4. 　前記銅合金は、Ｃｒを０．１質量％以上０．８質量％以下の範囲内、Ｓｉを０．４質量％以上０．８質量％以下の範囲内、Ｎｉを１．８質量％以上３．０質量％以下の範囲内で含み、その他が銅及び不純物からなる組成とされていることを特徴とする請求項１に記載の金属ＡＭ用銅合金粉末。 The copper alloy powder for metal AM according to claim 1, characterized in that the copper alloy contains Cr in the range of 0.1 mass% to 0.8 mass%, Si in the range of 0.4 mass% to 0.8 mass%, Ni in the range of 1.8 mass% to 3.0 mass%, and the remainder is copper and impurities.
  5. 　レーザー回折・散乱法にて測定された体積基準の５０％累積粒子径Ｄ５０が５μｍ以上１２０μｍ以下の範囲内とされていることを特徴とする請求項１に記載の金属ＡＭ用銅合金粉末。 The copper alloy powder for metal AM described in claim 1, characterized in that the volume-based 50% cumulative particle diameter D50 measured by a laser diffraction/scattering method is in the range of 5 μm to 120 μm.
  6. 　レーザー回折・散乱法にて測定された体積基準の１０％累積粒子径Ｄ１０が１μｍ以上８０μｍ以下の範囲内とされていることを特徴とする請求項１に記載の金属ＡＭ用銅合金粉末。 The copper alloy powder for metal AM described in claim 1, characterized in that the volume-based 10% cumulative particle diameter D10 measured by a laser diffraction/scattering method is in the range of 1 μm to 80 μm.
  7. 　レーザー回折・散乱法にて測定された体積基準の９０％累積粒子径Ｄ９０が１０μｍ以上１５０μｍ以下の範囲内とされていることを特徴とする請求項１に記載の金属ＡＭ用銅合金粉末。 The copper alloy powder for metal AM described in claim 1, characterized in that the volume-based 90% cumulative particle diameter D90 measured by a laser diffraction/scattering method is in the range of 10 μm to 150 μm.
  8. 　請求項１から請求項７のいずれか１項に記載の金属ＡＭ用銅合金粉末を準備する準備工程と、
    　前記金属ＡＭ用銅合金粉末を含む粉末床を形成する第１工程と前記粉末床において所定位置の前記金属ＡＭ用銅合金粉末を固化させて造形床を形成する第２工程とを順次繰り返して積層造形物を作製する造形工程と、
    　を備えることを特徴とする積層造形物の製造方法。     A preparation step of preparing the copper alloy powder for metal AM according to any one of claims 1 to 7;
    a molding process for producing a layered object by sequentially repeating a first process for forming a powder bed containing the copper alloy powder for metal AM and a second process for solidifying the copper alloy powder for metal AM at a predetermined position in the powder bed to form a molding bed;
    A method for manufacturing a layered object, comprising:
  9. 　前記造形工程後に３００℃以上純銅の融点以下の温度範囲で熱処理する熱処理工程を備えていることを特徴とする請求項８に記載の積層造形物の製造方法。 The method for manufacturing an additive manufacturing object according to claim 8, further comprising a heat treatment process in which the molding process is followed by a heat treatment at a temperature range of 300°C or higher and lower than the melting point of pure copper.
  10. 　前記造形工程後に８００℃以上純銅の融点以下の温度範囲で熱処理を行う第一熱処理工程と、前記第一熱処理後に３００℃以上８００℃未満の温度範囲で熱処理を行う第二熱処理工程と、を備えていることを特徴とする請求項８に記載の積層造形物の製造方法。 The method for manufacturing an additive manufacturing object according to claim 8, further comprising a first heat treatment process in which heat treatment is performed in a temperature range of 800°C or higher and lower than the melting point of pure copper after the molding process, and a second heat treatment process in which heat treatment is performed in a temperature range of 300°C or higher and lower than 800°C after the first heat treatment.
PCT/JP2023/038396 2022-10-24 2023-10-24 Metal additive manufacturing (am) copper alloy powder and method for producing addivtively manufactured article WO2024090449A1 (en)

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