WO2018079002A1

WO2018079002A1 - Laminated molding production method and laminated molding

Info

Publication number: WO2018079002A1
Application number: PCT/JP2017/028083
Authority: WO
Inventors: 坪田　龍介; 陽平岡; 啓岡本; 中本　貴之; 貴広菅原; 徳章四宮; 守武村; 壮平内田
Original assignee: 株式会社ダイヘン; 地方独立行政法人大阪産業技術研究所
Priority date: 2016-10-25
Filing date: 2017-08-02
Publication date: 2018-05-03
Also published as: JP6803021B2; TW201823480A; JP2018070914A

Abstract

This laminated molding production method comprises: a first step for preparing a copper alloy powder; a second step for producing a laminated molding using the copper alloy powder; and a third step for subjecting the laminated molding to heat treatment at a temperature of 300°C or higher. The copper alloy powder contains 0.10-1.00 mass% of chromium with the remainder being copper. The laminated molding is produced by sequentially repeating a step for forming a powder layer containing the copper alloy powder and a step for forming a molding layer by solidifying the copper alloy powder at a prescribed position in the powder layer, thereby laminating the molding layers.

Description

Method for manufacturing layered object and layered object

This disclosure relates to a method for manufacturing a layered object and a layered object.

Japanese Patent Application Laid-Open No. 2011-21218 (Patent Document 1) discloses a laser additive manufacturing apparatus (also referred to as “3D printer”) for metal powder.

JP 2011-21218 A

As a processing technique for metal products, the additive manufacturing method for metal powders has attracted attention. According to the additive manufacturing method, it is possible to create a complex shape that was impossible by cutting. So far, there have been reported production examples of layered objects made of iron alloy powder, aluminum alloy powder, titanium alloy powder and the like. That is, a layered object composed of an iron alloy, an aluminum alloy, a titanium alloy, or the like has been reported. However, there is no report of a layered object composed of a copper alloy.

An object of the present disclosure is to provide a layered object formed of a copper alloy.

[1] The method for manufacturing a layered object includes the following first step, second step, and third step.
First step: A copper alloy powder is prepared.

Second step: A layered product is produced from the copper alloy powder.
Third step: The layered object is heat-treated at a temperature of 300 ° C. or higher.

The copper alloy powder contains 0.10 mass% or more and 1.00 mass% or less of chromium, and the remaining copper.

The layered object is successively formed by (i) forming a powder layer containing copper alloy powder, and (ii) solidifying the copper alloy powder at a predetermined position in the powder layer to form a modeling layer, Manufactured by stacking modeling layers.
[2] In the third step, the layered object may be heat-treated at a temperature of 400 ° C. or higher.
[3] In the third step, the layered object may be heat-treated at a temperature of 700 ° C. or lower.
[4] In the third step, the layered object may be heat-treated at a temperature of 600 ° C. or lower.
[5] The layered object is a layered object formed of a copper alloy. The layered object contains 0.10 mass% or more and 1.00 mass% or less of chromium, and the remaining copper. The layered object has a relative density of 97% or more and 100% or less with respect to the theoretical density of the copper alloy, and has a conductivity of 50% IACS or more.
[6] The layered object may have a conductivity of 70% IACS or higher.

According to the present disclosure, a layered object formed of a copper alloy is provided.

FIG. 1 is a flowchart illustrating an outline of a method for manufacturing a layered object according to an embodiment of the present disclosure. FIG. 2 is an example of STL data. FIG. 3 is an example of slice data. FIG. 4 is a first schematic diagram illustrating the manufacturing process of the layered object. FIG. 5 is a second schematic diagram illustrating the manufacturing process of the layered object. FIG. 6 is a third schematic diagram illustrating the manufacturing process of the layered object. FIG. 7 is a fourth schematic diagram illustrating the manufacturing process of the layered object. FIG. 8 is a plan view of a test piece used in the tensile test. FIG. 9 is a graph showing the relationship between the heat treatment temperature and conductivity in the third step. FIG. 10 is a graph showing the relationship between the heat treatment temperature and the tensile strength in the third step. FIG. 11 is a graph showing the relationship between the heat treatment temperature in the third step and the Vickers hardness.

Hereinafter, an embodiment of the present disclosure (hereinafter referred to as “the present embodiment”) will be described. However, the following description does not limit the scope of claims.

First, how the present embodiment was found will be described.
Copper is frequently used in mechanical parts that require mechanical strength and high electrical conductivity. Examples of mechanical parts made of copper include welding torches and parts for power distribution equipment.

First, it was studied to manufacture a layered product with pure copper powder. However, depending on the pure copper powder, a desired layered product could not be obtained. Specifically, the layered object manufactured with pure copper powder has a large number of voids, and the density is greatly reduced with respect to a dense melted material. A decrease in density means a decrease in mechanical strength (for example, tensile strength). Furthermore, the electrical conductivity was greatly reduced compared to a dense smelted material. Various manufacturing conditions were investigated to improve density and conductivity. However, under any production conditions, the finished physical properties are not stable, and it is difficult to improve the density and conductivity.

Therefore, copper alloy powder was studied. As a result, by using a copper alloy powder having a specific composition, it is possible to manufacture a layered object having a practical density and conductivity, and further, the layered object is heat-treated at a specific temperature or more, so that It has been found that the mechanical strength and conductivity of the shaped object can be significantly improved. Hereinafter, this embodiment will be described in detail.
<Method for producing layered object>
FIG. 1 is a flowchart showing an outline of a method for manufacturing a layered object according to the present embodiment. The manufacturing method of this embodiment includes a first step (S100), a second step (S200), and a third step (S300). Hereafter, each process is demonstrated in order.
<< First Step (S100) >>
In the first step (S100), a copper alloy powder is prepared.

The copper alloy powder of this embodiment corresponds to toner or ink for a two-dimensional printer. In this embodiment, as long as the copper alloy powder of the specific composition mentioned later is prepared, the manufacturing method should not be specifically limited.

The copper alloy powder can be produced, for example, by a gas atomization method or a water atomization method. For example, first, a molten copper alloy is prepared. Molten metal is put into the tundish. Molten metal is dripped from the tundish. The molten metal being dropped is brought into contact with high-pressure gas or high-pressure water. Thereby, the molten metal is rapidly cooled and solidified to produce a copper alloy powder. In addition, the copper alloy powder can be produced by a plasma atomizing method, a centrifugal atomizing method, or the like.

In this embodiment, a copper alloy powder having a specific composition is used. That is, the copper alloy powder is a copper alloy powder containing 0.10% by mass or more and 1.00% by mass or less of chromium (Cr) and the remaining copper (Cu). The remainder may contain an impurity element in addition to Cu.

The impurity element may be, for example, an element intentionally added at the time of manufacturing the copper alloy powder (hereinafter referred to as “added element”). That is, the balance may contain Cu and additive elements. Examples of the additive element include nickel (Ni), zinc (Zn), tin (Sn), silver (Ag), beryllium (Be), zirconium (Zr), aluminum (Al), silicon (Si), cobalt (Co ), Titanium (Ti), magnesium (Mg), tellurium (Te) and the like. The impurity element may be, for example, an element inevitably mixed during the production of the copper alloy powder (hereinafter referred to as “inevitable impurity element”). That is, the balance may contain Cu and inevitable impurity elements. Examples of inevitable impurity elements include oxygen (O), phosphorus (P), iron (Fe), and the like. The balance may include Cu, additive elements, and inevitable impurity elements. The copper alloy powder may contain, for example, less than 0.30 mass% of additive elements and inevitable impurity elements in total. For example, the oxygen content of the copper alloy powder can be measured by a method based on “JIS H 1067: Method for quantifying oxygen in copper”.

The Cr content of the copper alloy powder is measured by an ICP emission analysis method based on “JIS H 1071: Method for quantifying chromium in copper and copper alloys”. The Cr content is measured at least three times. An average value of at least three times is adopted as the Cr content. The Cr content may be 0.15% by mass or more, 0.20% by mass or more, 0.22% by mass or more, or 0.51% by mass or more. It may be. The Cr content may be 0.94% by mass or less.

The Cu content of the copper alloy powder can be measured by a method based on “JIS H 1051: Copper determination method in copper and copper alloy”. The Cu content is measured at least three times. An average value of at least three times is adopted as the Cu content. The Cu content may be, for example, higher than 98.9% by mass and 99.9% by mass or less.

The copper alloy powder may be prepared to have an average particle diameter of 1 to 200 μm, for example. “Average particle size” indicates a particle size of 50% cumulative from the fine particle side in the volume-based particle size distribution measured by the laser diffraction scattering method. Hereinafter, the average particle diameter is also referred to as “d50”. d50 can be adjusted by, for example, gas pressure at the time of gas atomization, classification, or the like. d50 may be adjusted according to the lamination pitch of the layered object. d50 may be, for example, 5 to 50 μm, 50 to 100 μm, or 100 to 200 μm. The particle shape should not be particularly limited. The particles may be substantially spherical or irregularly shaped.
<< Second Step (S200) >>
In the second step (S200), a layered object is manufactured from the copper alloy powder.

Here, the powder bed melt bonding method is explained. However, addition production methods other than the powder bed fusion bonding method may be used. For example, a directional energy deposition method or the like may be used. Cutting may be performed during modeling.

Here, the aspect which solidifies copper alloy powder with a laser is demonstrated. However, the laser is merely an example, and as long as the copper alloy powder is solidified, the solidification means should not be limited to the laser. For example, an electron beam, plasma, or the like may be used.
(Data processing (S201))
First, 3D shape data is created by 3D-CAD or the like.

3D shape data is converted into STL data, for example. FIG. 2 is an example of STL data. In the STL data, for example, element division by the finite element method (so-called “meshing”) can be performed.

Slice data is created from the STL data. FIG. 3 is an example of slice data. STL data is divided into n layers. That is, the STL data is divided into a first modeling layer p1, a second modeling layer p2, ..., an nth modeling layer pn. The thickness of each layer (slice thickness d) may be, for example, 10 to 150 μm.
(Formation of powder layer (S202))
A powder layer containing copper alloy powder is formed.

FIG. 4 is a first schematic diagram illustrating the manufacturing process of the layered object. The laser additive manufacturing apparatus 100 includes a piston 101, a table 102, and a laser output unit 103. The table 102 is supported by the piston 101. The piston 101 is configured to move up and down the table 102. On the table 102, a layered object is formed.

The formation of the powder layer (S202) and the formation of the modeling layer (S203) described below may be performed, for example, in an inert gas atmosphere. This is for suppressing oxidation of the layered object. The inert gas may be, for example, argon (Ar), nitrogen (N ₂ ), helium (He), or the like. A reducing gas atmosphere may be used instead of the inert gas atmosphere. The reducing gas is, for example, hydrogen (H ₂ ) or the like. Further, a reduced pressure atmosphere may be used instead of the inert gas atmosphere.

Based on the slice data, the piston 101 lowers the table 102 by one layer. One layer of copper alloy powder is spread on the table 102. Thereby, the 1st powder layer 1 containing copper alloy powder is formed. For example, the surface of the first powder layer 1 may be smoothed by a squeezing blade (not shown) or the like. The first powder layer 1 may be formed substantially only from a copper alloy powder. The first powder layer 1 may include a laser absorbing material (for example, resin powder) in addition to the copper alloy powder.
(Formation layer formation (S203))
Subsequently, a modeling layer is formed.

The modeling layer constitutes a part of the layered object. FIG. 5 is a second schematic diagram illustrating the manufacturing process of the layered object. The laser output unit 103 irradiates a predetermined position of the first powder layer 1 with laser light based on the slice data. Before the laser light irradiation, the first powder layer 1 may be heated in advance. The copper alloy powder that has been irradiated with the laser light is solidified through melting and sintering. Thereby, the 1st modeling layer p1 is formed. That is, the modeling layer is formed by solidifying the copper alloy powder at a predetermined position in the powder layer.

The laser output unit 103 can be a general-purpose laser device. The light source of the laser light can be, for example, a fiber laser, a YAG laser, a CO ₂ laser, a semiconductor laser, a green laser, or the like. The output of the laser beam may be, for example, 20 to 1000 W or 200 to 500 W. The scanning speed of the laser beam can be adjusted within a range of 50 to 2000 mm / s, for example.

The energy density of the laser light can be adjusted within a range of 10 to 2000 J / mm ³ . The energy density is the following formula (I):
E = P ÷ (v × s × d) (I)
Is calculated by In the formula (I), “E” indicates the energy density [unit: J / mm ³ ] of the laser beam. “P” indicates the laser output [unit: W]. “V” indicates a scanning speed [unit: mm / s]. “S” indicates a scanning width [unit: mm]. “D” indicates slice thickness [unit: mm].

FIG. 6 is a third schematic diagram illustrating the manufacturing process of the layered object. After the first modeling layer p1 is formed, the piston 101 lowers the table 102 by one layer. The second powder layer 2 is formed by the same procedure as described above, and then the second modeling layer p2 is formed. Thereafter, the formation of the powder layer (202) and the formation of the modeling layer (203) are sequentially repeated, and the modeling layer is laminated, whereby a layered object is manufactured.

FIG. 7 is a fourth schematic diagram illustrating the manufacturing process of the layered object. Finally, the layered object 10 is completed by stacking the nth layer pn. In this embodiment, since the copper alloy powder having a specific composition is used, the layered object 10 can have a high relative density.
<< Third Step (S300) >>
In the third step (S300), the layered object is heat-treated at a temperature of 300 ° C. or higher. Thereby, it is expected that the mechanical strength (for example, tensile strength, Vickers hardness, etc.) of the layered object and the electrical conductivity of the layered object are greatly improved.

In this embodiment, a general heat treatment furnace can be used. The heat treatment temperature is measured by a temperature sensor attached to the heat treatment furnace. For example, if the set temperature of the heat treatment furnace is 300 ° C., it is considered that the layered object has been heat-treated at 300 ° C.

The layered object may be heat-treated, for example, from 1 minute to 10 hours, may be heat-treated from 10 minutes to 5 hours, or may be heat-treated from 30 minutes to 3 hours, or from 1 hour to 2 hours. It may be heat-treated for less than an hour. The atmosphere of the heat treatment can be, for example, air, nitrogen, argon, hydrogen, vacuum, or the like.

In the third step, the layered object may be heat-treated at a temperature of 400 ° C. or higher, or may be heat-treated at a temperature of 450 ° C. or higher. As a result, further improvement in mechanical strength and electrical conductivity is expected.

In the third step, the layered object may be heat-treated at a temperature of 700 ° C. or lower, may be heat-treated at a temperature of 600 ° C. or lower, or may be heat-treated at a temperature of 550 ° C. or lower. Thereby, for example, it is expected that the balance between mechanical strength and conductivity is improved. The layered object may be heat-treated at a temperature exceeding 700 ° C. However, at temperatures exceeding 700 ° C., the effect of improving mechanical strength and conductivity may be reduced.
<Layered object>
The layered object of the present embodiment is typically manufactured by the above manufacturing method.

The layered object of the present embodiment may have a complicated shape that cannot be realized by cutting. Furthermore, the layered object of this embodiment can be excellent in both mechanical strength and electrical conductivity. The layered object of the present embodiment can be a plasma torch as an example.
(composition)
The layered object is made of a copper alloy. The layered object contains 0.10 mass% or more and 1.00 mass% or less of Cr, and the remaining Cu. Similar to the aforementioned copper alloy powder, the balance may contain at least one of an additive element and an inevitable impurity element. The Cr content of the layered object is measured by the same measuring method as the measuring method of the Cr content of the copper alloy powder. The Cr content may be 0.15% by mass or more, 0.20% by mass or more, 0.22% by mass or more, or 0.51% by mass or more. It may be. The Cr content may be 0.94% by mass or less.

The Cu content of the layered object is also measured by the same measuring method as the measuring method of the Cu content of the copper alloy powder. The Cu content may be, for example, higher than 98.9% by mass and 99.9% by mass or less.
(Relative density)
The layered object has a relative density of 97% to 100% with respect to the theoretical density of the copper alloy. The “relative density” is calculated by dividing the actually measured density of the layered object by the theoretical density. The theoretical density indicates the density of the melted material having the same composition as the layered object. The measured density is measured by a method according to “JIS Z 2501: Sintered metal material—Test method for density, oil content and open porosity”. Water is used as the liquid. The relative density is measured at least 3 times. An average value of at least three times is adopted as the relative density.

A layered object having a high relative density is suitable for a component that requires high airtightness. Moreover, mechanical strength is also expectable, so that a relative density is high. The relative density may be 97.6% or more, 98% or more, 99% or more, 99.2% or more, 99. It may be 4% or more.
(Mechanical strength)
The layered object can have excellent mechanical strength. For example, the layered object may have a tensile strength of 250 MPa or more. That is, the layered object of the present embodiment can have a tensile strength equal to or higher than that of oxygen-free copper (UNS number C10200).

“Tensile strength” is measured by the following procedure.
For the measurement, a tensile test apparatus of grade 1 or higher defined in “JIS B 7721: Tensile Tester / Compression Tester—Calibration Method and Verification Method of Force Measurement System” is used. FIG. 8 is a plan view of a test piece used in the tensile test. A dumbbell-shaped test piece 20 shown in FIG. 8 is prepared. The dumbbell-shaped test piece 20 is attached to the grip of the tensile test apparatus. As the gripping tool, an object suitable for the shape of the dumbbell-shaped test piece 20 is used. The dumbbell-shaped test piece 20 is mounted so that a tensile stress is applied in the axial direction.

The dumbbell-shaped test piece 20 is pulled at a speed of 2 mm / min. Pulling is continued until the dumbbell-shaped test piece 20 breaks. The maximum tensile stress that appears before the dumbbell-shaped test piece 20 breaks is measured.

The tensile strength is calculated by dividing the maximum tensile stress by the cross-sectional area of the parallel portion 21. The cross-sectional area of the parallel portion 21 is 9.616 mm ² (= π × 3.5 mm × 3.5 mm ÷ 4). Tensile strength is measured at least three times. An average value of at least three times is adopted as the tensile strength. In addition, the dimension of each part of the dumbbell-shaped test piece 20 is as follows.

Total length (L0) of dumbbell-shaped test piece 20: 36 mm
Length of parallel portion 21 (L1): 18 ± 0.5 mm
Diameter of parallel part 21 (D1): 3.5 ± 0.05 mm
Radius (R) of shoulder 23: 10 mm
Length of the grip portion 22 (L2): 4.0 mm
Diameter of grip portion 22 (D2): 6.0 mm
The tensile strength can be adjusted by the heat treatment temperature in the third step. The tensile strength may be, for example, 300 MPa or more, 350 MPa or more, 400 MPa or more, 450 MPa or more, or 500 MPa or more. And it may be 550 MPa or more, or 600 MPa or more. The tensile strength may be, for example, 700 MPa or less, or 650 MPa or less.

The layered object may have a Vickers hardness of 70 HV or higher. “Vickers hardness” is measured by a method according to “JIS Z 2244: Vickers hardness test—test method”. The Vickers hardness can also be adjusted by the heat treatment temperature in the third step. The Vickers hardness may be, for example, 80 HV or more, 90 HV or more, 100 HV or more, 120 HV or more, or 140 HV or more. However, it may be 160 HV or higher, or 190 HV or higher. The Vickers hardness may be, for example, 250 HV or less, or 200 HV or less.
(conductivity)
The layered object has a conductivity of 50% IACS or more. That is, the layered object of the present embodiment may have a conductivity exceeding the conductivity of brass (UNS number C26000). “Conductivity” is measured by a commercially available eddy current conductivity meter. The electrical conductivity is evaluated on the basis of the electrical conductivity of annealed standard annealed copper (International Annealed Copper Standard, IACS). That is, the conductivity of the layered object is expressed as a percentage of the IACS conductivity. For example, the conductivity of the layered object is 50% IACS means that the conductivity of the layered object is half of the conductivity of IACS. Conductivity is measured at least three times. An average value of at least three times is adopted as the conductivity.

The conductivity can be adjusted by the heat treatment temperature in the third step. The layered object may have a conductivity of 70% IACS or higher, a conductivity of 80% IACS or higher, or a conductivity of 90% IACS or higher. The layered object may have a conductivity of 100% IACS or less, for example.

Examples will be described below. However, the following examples do not limit the scope of the claims.
A layered object was manufactured along the flowchart shown in FIG.

First, copper alloy powders A1 to A5 containing chemical components shown in Table 1 below were prepared (S100). These copper alloy powders were produced by a predetermined atomization method. For comparison, pure copper powder X and copper alloy powder Y were also prepared. Pure copper powder X is a powder made of commercially available pure copper as a raw material. The copper alloy powder Y is a powder made of a commercially available copper alloy (product name “AMPCO940”) as a raw material. Hereinafter, these powders are sometimes collectively referred to as “metal powders”.

A laser additive manufacturing apparatus having the following specifications was prepared.
Laser: Fiber laser, maximum output 400W
Spot diameter: 0.05-0.20mm
Scanning speed: ~ 7000mm / s
Lamination pitch: 0.02-0.08mm
Modeling size: 250mm x 250mm x 280mm
1. Pure copper powder X
Three-dimensional shape data is created (S201). (I) forming a powder layer containing a metal powder (S202), and (ii) forming a modeling layer by solidifying a metal powder at a predetermined position in the powder layer (S203) is sequentially repeated. The layers were laminated. Thus, with pure copper powder X, no. A layered object according to X-1 to X-40 was manufactured (S200). The layered object is a cylinder having a diameter of 14 mm and a height of 15 mm (unless otherwise specified, the following layered object is the same). The manufacturing conditions for the layered object are shown in Tables 2 and 3 below. The relative density and conductivity of the layered object were measured according to the method described above. The results are shown in Tables 2 and 3 below.

As shown in Tables 2 and 3 above, in the layered object manufactured with the pure copper powder X, even if the manufacturing conditions are fixed, the finished physical properties are not stable and vary greatly. In the column of “Relative Density” in Tables 2 and 3, “not measurable” indicates that a highly reliable density could not be measured because the layered object includes many voids. Pure copper may be considered to have a conductivity of 100% IACS. The layered object manufactured with the pure copper powder X has a significantly reduced electrical conductivity as compared with pure copper. Depending on the pure copper powder X, it is considered difficult to produce practical mechanical parts.
2. Copper alloy powder Y (commercial copper alloy powder)
According to the manufacturing conditions shown in Table 4 below, the same as above, No. Laminated shaped products according to Y-1 to Y-7 were manufactured. The layered object was heat-treated in a nitrogen atmosphere for 3 hours at the temperature indicated in the “heat treatment temperature” column of Table 4 below (S300). The layered object with “None” in the “Heat treatment temperature” column is not heat treated. The relative density and conductivity of the layered object were measured according to the method described above. The results are shown in Table 4 below.

As shown in Table 4 above, the electrical conductivity of the layered object manufactured using the copper alloy powder Y (commercial copper alloy powder) is higher than that of the commercial copper alloy (about 45.5% IACS). It had dropped significantly.
3. Copper alloy powder A1 (Cr content: 0.22% by mass)
According to the manufacturing conditions shown in Table 5 below, the same as above, No. A layered object according to A1-1 to A1-14 was manufactured. The layered object was heat-treated in a nitrogen atmosphere for 3 hours at the temperature indicated in the “heat treatment temperature” column of Table 5 below. Relative density, conductivity and tensile strength were measured according to the methods described above. The tensile strength was measured on a separately manufactured dumbbell-shaped test piece 20 (see FIG. 8) (the same applies hereinafter). The results are shown in Table 5 below.

As shown in Table 5 above, in the layered object manufactured using the copper alloy powder A1, variations in the finished physical properties were suppressed. These layered objects are considered to have mechanical strength and electrical conductivity that can be used as machine parts.
4). Copper alloy powder A2 (Cr content: 0.51% by mass)
According to the manufacturing conditions shown in Table 6 below, the same as above, No. A layered product according to A2-1 to A2-12 was manufactured. The layered object was heat-treated for 3 hours in a nitrogen atmosphere at the temperature indicated in the column of “heat treatment temperature” in Table 6 below. Relative density, conductivity and tensile strength were measured according to the methods described above. The results are shown in Table 6 below.

As shown in Table 6 above, in the layered object manufactured using the copper alloy powder A2, variations in finished physical properties were suppressed. These layered objects are considered to have mechanical strength and electrical conductivity that can be used as machine parts.
5). Copper alloy powder A3 (Cr content: 0.94% by mass)
According to the manufacturing conditions shown in Table 7 below, the same as above, No. A layered product according to A3-1 to A3-7 was manufactured. The layered object was heat-treated in a nitrogen atmosphere at a temperature indicated in the column of “heat treatment temperature” in Table 7 below for 3 hours. Relative density, conductivity and tensile strength were measured according to the methods described above. The results are shown in Table 7 below.

As shown in Table 7 above, in the layered object manufactured using the copper alloy powder A3, variations in finished physical properties were suppressed. These layered objects are considered to have mechanical strength and electrical conductivity that can be used as machine parts.
6). Examination of heat treatment temperature A layered product was manufactured under the manufacturing conditions shown in Tables 8 and 9 below. The relative density of the layered object was measured by the method described above. Furthermore, the layered object was heat-treated in a nitrogen atmosphere for 1 hour at the temperature shown in the column of “heat treatment temperature” in Tables 8 and 9 below. After heat treatment, the laminate model was measured for tensile strength, Vickers hardness and electrical conductivity. Vickers hardness was measured by the method described above. The results are shown in Tables 8 and 9 below.

As shown in Tables 8 and 9 above, a layered object composed of a copper alloy and having a Cr content of 0.10% by mass to 1.00% by mass is stably 97% to 100%. And had a relative density of Furthermore, when the layered object is heat-treated at a temperature of 300 ° C. or higher, a tendency that the mechanical strength and the electrical conductivity are greatly improved is recognized.

Hereinafter, the results will be described with reference to FIGS. 9 to 11, for example, “0.2Cr” in the legend indicates that the Cr content is 0.22% by mass. For convenience, the second decimal place is rounded off in the legend. The layered object that has not been heat-treated is considered to have been heat-treated at 25 ° C., and a graph is created.

FIG. 9 is a graph showing the relationship between the heat treatment temperature and conductivity in the third step. In the range where the heat treatment temperature is 300 ° C. or higher, the conductivity of the layered object is significantly improved. Even when the heat treatment temperature is 700 ° C., the effect of improving the conductivity is recognized. Therefore, the upper limit of the heat treatment temperature may be 700 ° C. However, it is expected that the effect of improving the conductivity can be obtained even in the range where the heat treatment temperature exceeds 700 ° C.

FIG. 10 is a graph showing the relationship between the heat treatment temperature and the tensile strength in the third step. As shown in FIG. 10, the tensile strength of the layered object is significantly improved when the heat treatment temperature is 300 ° C. or higher. The range of improvement in tensile strength when the heat treatment temperature is changed from 400 ° C. to 450 ° C. is particularly remarkable. The tensile strength reaches a peak at around 500 ° C. and then decreases gradually.

FIG. 11 is a graph showing the relationship between the heat treatment temperature and the Vickers hardness in the third step. Vickers hardness also shows the same tendency as tensile strength.

9 to 11, the heat treatment temperature may be 300 ° C. or higher and 700 ° C. or lower, 400 ° C. or higher and 600 ° C. or lower, or 450 ° C. from the viewpoint of the balance between mechanical strength and electrical conductivity. It may be 550 ° C. or lower or 450 ° C. or higher and 500 ° C. or lower.

It should be considered that the embodiments and examples disclosed this time are examples in all respects and are not restrictive. The technical scope defined by the claims includes meanings equivalent to the claims and all changes within the scope.

1. 1st powder layer, 2nd powder layer, 10 layered object, 20 dumbbell specimen, 21 parallel part, 22 grip part, 23 shoulder part, 100 laser additive manufacturing apparatus, 101 piston, 102 table, 103 laser output Part, p1 first modeling layer, p2 second modeling layer, pn nth modeling layer.

Claims

A first step of preparing a copper alloy powder;
Including a second step of manufacturing a layered object using the copper alloy powder, and a third step of heat-treating the layered object at a temperature of 300 ° C. or higher,
The copper alloy powder is
Containing 0.10% by mass or more and 1.00% by mass or less of chromium, and the remaining copper
The layered object is
Forming a powder layer including the copper alloy powder and solidifying the copper alloy powder in a predetermined position in the powder layer to sequentially form a modeling layer, and stacking the modeling layer Manufactured by,
Manufacturing method of layered object.
In the third step, the layered object is heat-treated at a temperature of 400 ° C. or higher.
The method for producing a layered object according to claim 1.
In the third step, the layered object is heat-treated at a temperature of 700 ° C. or lower.
The manufacturing method of the laminate-molded article of Claim 1 or Claim 2.
In the third step, the layered object is heat-treated at a temperature of 600 ° C. or lower.
The method for producing a layered object according to any one of claims 1 to 3.
A layered object composed of a copper alloy,
Containing 0.10% by mass or more and 1.00% by mass or less of chromium, and the balance of copper,
Having a relative density of 97% or more and 100% or less with respect to the theoretical density of the copper alloy, and having a conductivity of 50% IACS or more,
Laminated model.
Having a conductivity of 70% IACS or higher,
The layered object according to claim 5.