WO2016013493A1

WO2016013493A1 - Production method of casting alloy

Info

Publication number: WO2016013493A1
Application number: PCT/JP2015/070466
Authority: WO
Inventors: 隆彦加藤; 孝介桑原; 正藤枝; 青田　欣也; 高橋　勇; 佐竹　弘之; 山賀　賢史; 元村上
Original assignee: 株式会社日立製作所
Priority date: 2014-07-23
Filing date: 2015-07-17
Publication date: 2016-01-28

Abstract

In order to provide an alloy structure of any shape and size that has a high uniformity of elemental composition and mechanical strength distribution, and has excellent high temperature strength and corrosion resistance, this production method of a casting alloy comprises a melting step for melting raw material metal ingots to form a melt, a peroxidation step for blowing an oxygen gas into the melt to form slag, a separation step for separating the slag floating on the surface of the melt from the melt, a deaeration step for deaerating the gas component in the melt by blowing an argon gas into the melt from which the slag has been separated, and a casting step for casting the deaerated melt to form a cast alloy.

Description

Method of manufacturing cast alloy

The present invention relates to a method of manufacturing a cast alloy.

Alloy materials are used in a variety of applications including structural members that form the framework of structures and devices, various mechanical members, etc. For applications in harsh environments where it is difficult to use steel or aluminum materials It is often used. For example, nickel-based alloys, cobalt-based alloys and the like have been developed which are applied to turbine members and the like provided in aircraft, generators and the like and can be applied to ultra-high heat environments of 1000 ° C. or more. In addition, high alloy steels and the like that can exhibit high corrosion resistance and wear resistance even under such ultra-high heat environment are also developed.

In recent years, high-entropy alloys (HEAs) as a type of alloy material
A multi-element alloy called is attracting attention. Generally, a high entropy alloy is considered to be an alloy which is composed of about five or more kinds of plural elements and which contains each element at an equal atomic ratio or an atomic ratio in the vicinity thereof. Since it has the feature that the rate of atomic diffusion is slow and is excellent in heat resistance, high temperature strength, corrosion resistance and the like, application to applications in severe environments is expected.

As a technique to which a high entropy alloy is applied, for example, Patent Document 1 discloses a method for producing a cemented carbide composite material, in which at least one ceramic phase powder and a multicomponent high entropy alloy powder are mixed to form a mixture The steps of: compacting the mixture; and sintering the mixture to form a cemented carbide composite, wherein the multicomponent high entropy alloy powder comprises 5 to 11 major elements, each major element There is disclosed a manufacturing method in which 5% to 35% by mole of the multicomponent high entropy alloy powder is contained.

In addition, Non-Patent Document 1 discloses that in a high entropy alloy having an equiatomic ratio of Al, Co, Cr, Fe, and Ni, analysis of the dimensional effect on the microstructure and mechanical properties is disclosed.

JP, 2009-074173, A

In order to apply a high-entropy alloy as a material of a structural member such as a structural member or a mechanical member and manufacture a structural body taking advantage of its characteristics, the main elements constituting the high-entropy alloy are dissolved in an equiatomic ratio In addition, it is desirable to form a solid solution phase so that the uniformity of the elemental composition distribution is high throughout the structure having a wide variety of shapes and sizes.

However, in the conventional high entropy alloy manufacturing method exemplified by the mechanical alloying method disclosed in Patent Document 1 and the arc melting method disclosed in Non-patent Document 1, the elemental composition distribution, the melting rate, the cooling rate Unevenness easily occurs, etc., and it is difficult to form a solidified structure having a uniform elemental composition distribution, and it is difficult to enlarge the solid solution phase in which each element is substantially solid-solved at an equal atomic ratio . For example, the alloy material disclosed in Non-Patent Document 1 is only a small piece of 10 mm in diameter × 70 mm in height (volume 5495 mm ³ ) even for the largest prototype material, and it is difficult to apply as a material of a structure.

In particular, when a relatively large structure is to be cast, a process of melting a large amount of metal or solidifying a molten metal is required, so unevenness of element composition distribution, melting rate, cooling rate, etc. The influence is strongly expressed, and there is a problem that it becomes difficult to form a solid solution phase of the high entropy alloy. In addition, high-entropy alloys have good high-temperature strength and corrosion resistance, but have a feature that the speed of atomic diffusion is slow. Therefore, depending on heat treatment after solidification, uniformity of elemental composition and mechanical strength is ensured. It is difficult. In addition, because it is difficult to process, it is also difficult to form a structure of an arbitrary shape by cutting out after solidification etc., and obtain a structure of high entropy alloy with high uniformity of distribution of elemental composition and mechanical strength. There is a difficult current situation.

Therefore, an object of the present invention is to provide an alloy structure having an arbitrary shape and size with high uniformity of distribution of elemental composition and mechanical strength, and having good high temperature strength and corrosion resistance.

In order to solve the problems, the present invention adopts, for example, the configuration described in the claims.

According to the present invention, it is possible to provide an alloy structure of any shape and dimension with high uniformity of distribution of elemental composition and mechanical strength, and good temperature strength and corrosion resistance.

It is a conceptual diagram which shows an example of the process of the manufacturing method of the alloy material which concerns on this embodiment. It is sectional drawing which showed the outline of the metal structure which an alloy structure has. (A) is a cross-sectional view of the alloy structure according to the present embodiment, (b) is an enlarged cross-sectional view of part A in (a), (c) is a schematic view of the metal structure of the alloy material according to the comparative example. It is sectional drawing which showed. It is a schematic flowchart which shows an example of the manufacturing method of the alloy powder used as a raw material of an alloy structure. It is the figure which showed an example of progress of the density | concentration change of the impurity element in the alloy powder prepared using the vacuum carbon deoxidation method. FIG. 7 is a view showing the shape and dimensions of an alloy structure according to Example 3; FIG. 16 is a compression true stress-compression true strain diagram in the alloy structure according to Example 3. FIG. 18 is a view showing test temperature dependency of tensile strength in the alloy structure according to Example 4. It is a figure which shows the range of the main component which can form a solid solution phase in an alloy structure. It is a figure which shows the shape dimension of the alloy structure which concerns on Example 6. FIG.

Hereinafter, an alloy structure according to an embodiment of the present invention will be described. In addition, about the structure which is common in each figure, the same code | symbol is attached | subjected and the duplicate description is abbreviate | omitted.

The alloy structure according to the present embodiment is mainly composed of iron (Fe) and at least four other elements (hereinafter sometimes referred to as non-Fe main component elements) that form a solid solution with Fe. It is a metal shaped object which is made of an entropy alloy and formed into a desired shape and dimension by additive manufacturing. This alloy structure contains the non-Fe main component element and the element of Fe at an atomic concentration in the range of 5 at% or more and 30 at% or less for each individual element, and at least four of these elements are It has an elemental composition with substantially equal atomic proportions. The non-Fe main component element and the atoms of Fe form a solid solution phase in which these plural types of elements are solidly dissolved. Therefore, this alloy structure has high heat resistance, high temperature strength, wear resistance, and corrosion resistance as general properties as a high entropy alloy. In addition, as described later, it has a unique solidified structure formed by additive manufacturing, and has a feature of high uniformity of distribution of elemental composition and mechanical strength.

In the alloy structure according to the present embodiment, the main crystals substantially consist of a collection of columnar crystals at normal temperature and normal pressure. The presence ratio of columnar crystals is at least 50% or more in an occupied area ratio in any cross section of the solidified structure, and is 90% or more or 95% or more according to the formation condition of the solidified structure in the manufacturing method described later It is also possible. In addition, the average crystal grain size of the columnar crystals is 100 μm or less, and it is also possible to further refine it to 10 μm or less. The average grain size can be determined according to the method defined in JIS G 0551 (2013).

The main crystals of the alloy material structure have a crystal structure of face-centered cubic lattice or body-centered cubic lattice at normal temperature and normal pressure. By selectively designing the composition, it is possible to make the existing ratio of the crystal structure of the face-centered cubic lattice 90% or more or 95% or more in the occupied area ratio in any cross section of the solidified structure. In addition, the proportion of the crystal structure of the body-centered cubic lattice can be 90% or more or 95% or more in an occupied area ratio in an arbitrary cross section of the solidified structure.

A non-Fe main component element is an element having an atomic number 13 to an atomic number 79 included in Groups 3 to 16 (Group 3A to Group 6B) of the periodic table of elements, and an atomic radius with respect to a Fe atom At least four or more elements are selected from elements other than Fe having a ratio of 0.83 or more and 1.17 or less. As such non-Fe main component elements, specifically, Al, Si, P, Ti, V, Cr, Mn, Co, Ni, Cu, Zn, Ga, Ge, As, Se, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Sn, Sb, Te, Ta, W, Re, Os, Ir, Pt, Au can be mentioned. By setting the alloy structure to such an elemental composition, an atomic volume effect is exhibited, and a stable solid solution phase exhibiting an action as a high entropy alloy can be formed.

As the non-Fe main component element, it is more preferable to contain an element having a ratio of atomic radius to Fe atom of 0.92 or more and 1.08 or less, and it is more preferable to contain only such an element together with Fe. Specific examples of non-Fe main component elements that become main component elements with Fe include Si, V, Cr, Mn, Co, Ni, Cu, Zn, Ga, Ge, As, Se, Mo, Tc, Ru, Rh, Re, Os, Ir are mentioned. Among these, the more preferable non-Fe main component is V, Cr, Mn, Co, Ni, Cu, Ge, Mo, and it is particularly preferable to contain Co, Cr and Ni.

The elements of the alloy of the members are used as the alloy of the members of the members of the alloy and the members. CoCrFeNiCuAl, MnCrFeNiAl, MoCrFeNiCu, TiCoCrFeNi, TiCoCrFeNiMo, CoCrFeNiCuAl It can be exemplified MnCrFeNiCu, TiCoCrFeNi, TiCoCrFeNiAl, CoCrFeNiMo, CoCrFeNiAlMo, TiCoCrFeNiCu, CoCrFeNiCuAlMn, TiCoCrFeNiMo, CoCrFeNiCuAlV, TiCoCrFeNiCuVMn, AlTiCoCrFeNiCuVMn, CoCrFeNiCuAlMn, CoCrFeNiAlMo, CoCrFeNiCuAlMo, the TiCoCrFeNiCu like. In these elemental compositions, the atomic composition (molar ratio of atoms) of each element is an atomic composition in which the atomic concentration is in the range of 5 at% to 30 at%, and at least four elements have substantially equal atomic proportions. Various values can be taken as long as However, when Ti is contained as a component element, Ti should not be a component having the maximum atomic concentration among the component elements, and preferably the atomic concentration per alloy structure is 5 at% or more and less than 10 at%.

The alloy structure is allowed to contain elements of non-Fe main component element and Fe, as well as other unavoidable impurities. As an element of unavoidable impurities, P, Si, S, Sn, Sb, As, Mn, O, N etc. are mentioned, for example. However, P is preferably 0.005 wt% or less, more preferably 0.002 wt% or less, Si is preferably 0.040 wt% or less, more preferably 0.010 wt% or less, and S is Preferably, the content is 0.002 wt% or less, more preferably 0.001 wt% or less, for Sn preferably 0.005 wt% or less, more preferably 0.002 wt% or less, for Sb preferably 0.002 wt% Or less, more preferably 0.001 wt% or less, As 0.005, preferably 0.005 wt% or less, more preferably 0.001 wt% or less, Mn, preferably 0.050 wt% or less, more preferably 0 Limit to .020 wt% or less. In addition, O is preferably 0.001 wt% or less (10 ppm or less), more preferably 0.0003 wt% or less (3 ppm or less), and N is preferably 0.002 wt% or less (20 ppm or less), more preferably Is limited to 0.001 wt% or less (10 ppm or less). Thus, by limiting the concentration of unavoidable impurities contained in the alloy structure, the uniformity of the distribution of the elemental composition and the mechanical strength can be further enhanced regardless of the shape and size of the structure. In the case where an element of P, Si, Sn, Sb, As or Mn is contained in the alloy structure as a non-Fe main element, the concentration of the element need not be limited in this manner.

The alloy structure contains a non-Fe main component element and at least four elements of Fe in a substantially equiatomic ratio in the atomic concentration range of 5 at% or more and 23.75 at% or less. At this time, other elements are contained in an atomic concentration range of 5 at% or more and 30 at% or less, and the balance is composed of unavoidable impurities. As described above, when at least four elements are contained in an equiatomic ratio, the mixed entropy term of the free energy is increased, so that the solid solution phase is stabilized. In the present specification, substantially equal atomic ratio means that the difference in atomic concentration is in the range of less than 3 at%.

The element type and atomic ratio that constitute the alloy structure can be selected and designed by, for example, determining the enthalpy of formation, the entropy or the Gibbs energy by thermodynamic calculation. For example, the ratio of the atomic concentration of at least four elements contained in equal atomic proportions to the other elements can be appropriately changed within the aforementioned atomic concentration range. The crystal structure of the alloy structure can be changed by changing the ratio of the atomic concentrations of these main component elements, and the mechanical strength, the spreadability, the hardness, the density, and the like can be adjusted. As thermodynamic calculation, a first principle calculation method, a Calphad (Calculation of phase diagrams) method, a molecular dynamics method, a phase-field method, a finite element method or the like can be used in combination as appropriate.

The alloy structure contains, for example, Al in an atomic concentration range of 5 at% or more and 30 at% or less, and substantially in an atomic concentration range of 15 at% or more and 23.75 at% or less of Co, Cr, Fe and Ni. It can be set as the elemental composition contained by an equiatomic ratio. When the atomic concentration of Al contained in the alloy structure is reduced in the range of 5 at% or more and 30 at% or less, the main phase of the alloy structure can be made to have a crystal structure of face-centered cubic lattice. On the other hand, when the atomic concentration of Al is increased in the range of 5 at% or more and 30 at% or less, the main phase of the alloy structure can be made to have a crystal structure of a body-centered cubic lattice. Further, when the atomic concentration of Al contained in the alloy structure is 5 at% or more, there is a low possibility that the mechanical strength of the alloy structure is excessively reduced, and on the other hand, the atomic concentration of Al contained in the alloy structure is 30 at. If the content is less than 10%, the main phase of the alloy structure does not easily become an Al-based intermetallic compound, and therefore, the possibility of the ductility of the alloy material being excessively reduced is low.

Similarly, Co is contained substantially at an atomic ratio of 5 at% to 30 at%, and Al, Cr, Fe and Ni at an atomic concentration range of 15 at% to 23.75 at%, or Cr at 5 at% More than 30 at% or less, Al, Co, Fe and Ni are contained in an equiatomic ratio substantially in an atomic concentration range of 15 at% or more and 23.75 at% or less, or 5 at% or more and 30 at% or less of Fe, Al, Co , Cr and Ni in an atomic ratio range of 15 at% or more and 23.75 at% or less substantially, or at least 5 at% or more and 30 at% or less of Ni, and 15 at% or more of Al, Co, Cr, and Fe It is also possible to contain substantially equiatomic proportions in the atomic concentration range of 23.75 at% or less.

Next, a method of manufacturing the alloy structure according to the present embodiment will be described.

The alloy structure according to the present embodiment can be manufactured by powder laminate molding using an alloy powder. A method of manufacturing an alloy structure as a three-dimensional shaped object of a desired shape and size by melting and solidifying the alloy powder to form a solidified structure and arranging a large number of solidified structures integrally with the surroundings. . The method for producing an alloy structure according to the present embodiment includes a powder preparation step of preparing an alloy powder used for layered formation, and a lamination forming step of shaping an alloy structure using the prepared alloy powder.

In the powder preparation step, an alloy powder is prepared which contains the same main component and additive elements as the alloy structure to be produced, and has an elemental composition in which the main components are substantially equiatomic. The alloy powder is preferably in the form of a particle assembly in which each powder particle has substantially the same elemental composition as the alloy structure to be produced. In addition, when heating the alloy powder in the solidified layer forming step, a part of the alloy components may be volatilized and lost, so the range of the atomic concentration is set to a high range in consideration of the composition change due to such volatilization. It is also good.

As a method of preparing the alloy powder, a method of producing a metal powder which is conventionally and generally used can be used. For example, an atomizing method in which a molten metal alloy is sprayed with a fluid to be scattered and solidified, a crushing method in which a molten metal alloy is solidified and then mechanically crushed, a metal alloy is mixed, and pressure welding and crushing are repeated to form an alloy An appropriate method such as an ingot method, a melt spinning method in which a molten alloy of alloy is caused to flow down on a rotating roll to solidify can be used.

As a method of preparing the alloy powder, the atomizing method is suitable, and the gas atomizing method is more preferably used, and the gas atomizing method performed in an inert gas atmosphere using an inert gas as a fluid is more preferably used. According to such a preparation method, it is possible to prepare an alloy powder having high sphericity and less contamination with impurities. And, when the sphericity of the alloy powder is increased, the resistance at the time of spreading the alloy powder in lamination molding can be suppressed, so that unevenness of the alloy powder can be reduced. Further, by using an inert gas, the mixing of oxide impurities and the like is suppressed, so that the metal structure of the manufactured alloy material can be made more uniform.

The alloy powder can have an appropriate particle diameter according to the melting conditions such as the method of spreading the alloy powder in lamination molding and the output of a heat source for melting the alloy powder. However, in general, the particle size distribution of the alloy powder is preferably in the range of 1 μm to 500 μm. If the particle size of the alloy powder is 1 μm or more, rolling up and floating of the alloy powder are suppressed, or the oxidation reactivity of the metal is suppressed, thereby reducing the possibility of dust explosion and the like. On the other hand, if the particle diameter of the alloy powder is 500 μm or less, it is advantageous in that the surface of the solidified layer formed in lamination molding tends to be smooth. Moreover, it becomes possible to suppress the output of the heating means for melting the alloy powder, and it becomes easy to control the melting speed of the alloy powder and the range of the heated region when locally heating the alloy powder. The shaping accuracy of the body and the uniformity of the solidified tissue can be easily secured.

FIG. 1: is a conceptual diagram which shows an example of the process of the manufacturing method of the alloy structure which concerns on this embodiment.

In the method of manufacturing an alloy structure according to the present embodiment, the layered manufacturing process shown in order from FIG. 1 (a) to (g) is repeatedly performed to perform three-dimensional formation of the alloy structure. The lamination molding process can be carried out using a powder lamination molding apparatus for metal generally used conventionally, and the alloy powder prepared in the powder preparation process is a raw material of such lamination molding process. It is used as a powder. As a heating means provided in the layered modeling apparatus, for example, one based on an appropriate heating principle such as electron beam heating, laser heating, microwave heating, plasma heating, condensing heating, high frequency heating and the like is used. Among these, a lamination molding apparatus by electron beam heating or laser heating is particularly preferable. Electron beam heating or laser heating is relatively easy to control the output of the heat source, the miniaturization of the heated region of the alloy powder, the shaping accuracy of the alloy structure, and the like.

Specifically, the layer forming process includes a powder spreading process and a solidified layer forming process. In the layered manufacturing process, a layered solidified structure (coagulated layer) is formed through steps shown in FIG. 1A to FIG. 1G sequentially, and formation of the layered solidified structure (coagulated layer) is repeated. , Forming an alloy structure consisting of a set of solidified structures.

As shown in FIG. 1A, the layered manufacturing apparatus is provided with a vertically movable piston having a base mounting table 21 at its upper end. A processing table 22 which is not interlocked with the piston is provided around the substrate mounting table 21, and a powder feeder (not shown) for supplying the raw material powder 10 onto the processing table 22 spreads the supplied raw material powder 10. The recoater 23, the heating means 24 for heating the raw material powder 10, an air blast (not shown) for removing the raw material powder 10 on the processing table 22, a temperature controller (not shown) and the like are provided. The processing table 22 and these devices are accommodated in a chamber, and the atmosphere in the chamber is a vacuum atmosphere or an inert gas atmosphere such as argon gas according to the type of the heating means 24 and the atmosphere pressure and temperature are It is supposed to be managed. When performing layered manufacturing, the base material 15 is previously mounted on the base material mounting table 21 and aligned so that the surface to be molded (upper surface) of the base material 15 and the upper surface of the processing table 22 are flush with each other .

Any appropriate material can be used as the base material 15 as long as it has heat resistance to the heating by the heating means 24. In the method of manufacturing the alloy structure, the layered structure of the alloy structure is performed on the surface to be formed of the base material 15 to form a shaped object in a state in which the base material 15 and the alloy structure are integrated. It will be obtained. Therefore, as the base material 15, the base material 15 having a suitable shape such as a flat plate can be used on the assumption that it is separated from the alloy structure by a cutting process or the like. Alternatively, it is also possible to use a structural member of any shape having a surface to be shaped, a mechanical member or the like as the base material 15 on the assumption that the base material 15 and the alloy structure function in an integrated state.

In the powder spreading step, the prepared alloy powder 10 is spread on the surface to be shaped. That is, the alloy powder 10 is spread on the base material 15 placed on the layered modeling apparatus in the first powder spreading process in the layered modeling. The spreading of the alloy powder 10 is, as shown in FIG. 1 (b), the alloy powder 10 (see FIG. 1 (a)) supplied on the processing table 22 by a powder feeder (not shown). It can carry out by sweeping so that it may pass on the surface (base material 15), and laying the alloy powder 10 in thin layers. The thickness of the thin layer of the alloy powder 10 formed by spreading can be appropriately adjusted according to the output of the heating means for melting the alloy powder 10, the average particle diameter of the alloy powder 10, etc. Is in the range of about 10 μm to 1000 μm.

In the solidified layer forming step, the expanded alloy powder 10 is locally heated and melted and then solidified, and the solidified layer is obtained by scanning the heated region by the local heating with respect to the plane on which the alloy powder 10 is expanded. Shape 40 According to two-dimensional shape information obtained from three-dimensional shape information (such as 3D-CAD data) representing the three-dimensional shape of the alloy structure to be manufactured, the formation of the solidified layer 40 (see FIG. It is carried out by scanning the heated region by the heating means 24. The two-dimensional shape information virtually divides the three-dimensional shape of the alloy structure to be manufactured by a predetermined thickness interval and virtually specifies the shape of each thin layer when divided into a plurality of thin layer groups. It is information. According to such two-dimensional shape information, a solidified layer 40 having a predetermined two-dimensional shape and thickness is formed.

The local heating of the alloy powder 10 is carried out by limiting the heated region on the spread alloy powder 10 by the heating means 24 as shown in FIG. This is performed by selectively melting the part so that a minute molten pool (melting part 20) is formed. The size of the molten portion 20 formed by melting the alloy powder 10 is preferably 1 mm or less in diameter. By limiting the melting portion 20 to such a minute size, the shaping accuracy of the alloy structure and the uniformity of the elemental composition in the solidified structure can be enhanced.

The region to be heated by the local heating of the alloy powder 10 is scanned so as to move parallel to the surface to be shaped, as shown in FIG. 1 (d). The scanning of the heated region can be performed by scanning the irradiation spot of the heat source with a galvano mirror or the like in addition to scanning of the main body of the heating means 24, and it is performed by an appropriate method such as raster scanning. At this time, overlap scanning with a plurality of radiation sources may be performed to flatten the irradiated energy density. Then, local heating of the region where the alloy powder 10 is not yet melted is newly performed by scanning the heated region, and heating of the region where the alloy powder 10 is already melted to form the molten portion 20 is stopped, The molten portion 20 is cooled and solidified under the ambient temperature. The solidified portion 30 formed by the solidification of the molten portion 20 forms a dense aggregate of the solidified portion 30 while being integrated with the base material and the solidified portion 30 already formed.

The scanning speed, output, energy density and scanning width of the heating means 24 are estimated from the elemental composition of the alloy powder 10, the particle size distribution, the material of the base 15, the positional relationship between the melting portion 20 and the solidification portion 30, chamber temperature etc. It may be adjusted appropriately based on heat conduction and heat radiation. Further, the cooling temperature for cooling the molten portion 20 may be set in consideration of dimensional change, thermal strain and the like according to the elemental composition of the alloy structure. By performing scanning while maintaining the size of the melting portion 20, the melting rate, the cooling rate, the time interval of melting and cooling, etc. in a predetermined range, the strength distribution of the shaped alloy structure is made uniform, It is possible to reduce residual stress and surface roughness.

As shown in FIGS. 1 (c) to 1 (e), melting and solidification of the alloy powder 10 are repeated on the base material 15 placed on the base material placement table 21 to form a set of solidification parts 30. A solidified layer 40 having a predetermined two-dimensional shape and thickness is formed. After the unmelted alloy powder 10 remaining on the periphery and the upper surface of the formed solidified layer 40 is removed by air blasting, as shown in FIG. 1 (f), the base material mounting table 21 is solidified The height is lowered corresponding to the thickness of the layer 40 so that the new surface to be shaped of the upper surface of the solidified layer 40 is flush with the upper surface of the processing table 22.

After alignment, the powder spreading process is performed in the same manner as in FIGS. 1 (a) to 1 (b), and as shown in FIG. 1 (g), a new surface is formed on the upper surface of the solidified layer 40 already formed. The supplied alloy powder 10 is spread. Thereafter, in the same manner as in FIGS. 1 (c) to 1 (e), the solidified layer shaping step is performed, and the solidified layer 40 of the next layer is laminated. The solidified portion 30 to be laminated is integrated with a part of the lower solidified layer 40 to be densely sintered. Thereafter, similarly, the powder spreading process and the solidified layer forming process with the upper surface of the formed solidified layer 40 as a surface to be shaped can be repeated to laminate and model the alloy structure having a desired shape and size.

In the solidified layer forming step, shape forming processing and surface processing of the solidified portion 30 to the solidified layer 40 can be performed in a high temperature state until the solidified portion 30 is formed after the alloy powder 10 is melted. . Such processing is performed, for example, in a metal or an alloy in a state where the surface temperature of the molten portion 30 to the solidified portion 40 is about 500 ° C. or higher, preferably 50% to 75% of the melting point (Tm) of the alloy. It can be carried out by processing using a tool made of an inorganic or inorganic composite material such as a diamond powder, an intermetallic compound powder, or a powder compact of tungsten carbide or the like. By such processing, it is possible to form or decorate an alloy structure that is difficult to work into a shape with higher precision.

A hot isostatic pressing (HIP) treatment may be separately performed on the alloy structure layered and shaped by repeating the powder spreading step and the solidified layer shaping step. By subjecting the alloy structure to hot isostatic pressing, the solidified structure of the alloy structure may be made more compact or defects of the solidified structure may be removed in some cases.

According to the manufacturing method of the alloy structure which performs such a lamination molding process repeatedly, and performs three-dimensional modeling, it manufactures an alloy structure which makes a columnar crystal a main crystal by a collection of minute solidification structure with desired shape size. Can. In addition, each elemental composition of the minute solidified structure (solidified portion 30) well reflects the elemental composition of the used alloy powder, so uniformity of elemental composition distribution and uniformity of mechanical strength distribution A high solid solution phase can be formed. Furthermore, since the solidified structure (solidified portion 30) is formed by heating from one direction, and the solidified structure (solidified layer 40) in which the crystal growth direction is oriented in substantially one direction can be stacked, the anisotropy is high. An alloy structure can be formed.

Next, the metallographic structure of the alloy structure formed by additive manufacturing will be described.

FIG. 2 is a cross-sectional view schematically showing the metal structure of the alloy structure. (A) is a cross-sectional view of the alloy structure according to the present embodiment, (b) is an enlarged cross-sectional view of part A in (a), (c) is a schematic view of the metal structure of the alloy material according to the comparative example. It is sectional drawing which showed.

As shown in FIG. 2 (a), the alloy structure 1 according to the present embodiment has a metal structure derived from the above-described manufacturing method by lamination molding, and a solidified structure (solidified structure formed by solidification of a melted alloy) It consists of a set of parts 30). In addition, in FIG. 2 (a), a part of the alloy structure manufactured by lamination molding is extracted, and the cross section is shown. Each solidified structure (solidified portion 30) has a substantially hemispherical original shape derived from the contour shape of the molten pool (melted portion 20) by local heating, and is integrated with other solidified portions 30 in the periphery. It forms a fine metal structure. In addition, the solidified portions 30 are arranged in a two-dimensional manner, with the arc side facing in the same direction, so that a layered solidified layer 40 formed of a set of solidified portions 30 is formed. Then, by laminating a large number of solidified layers 40 formed in this manner, a metal structure in which solidified portions 30 are three-dimensionally arranged is formed. However, depending on forming conditions such as scanning speed and scanning width in additive manufacturing, the solidified portion 30 forming the solidified layer 40 may be integrated with other solidified portions 30 around the same layer, or the chord side of each solidified portion 30 Because it may be integrated with the other solidified layer 40 laminated, the substantially hemispherical original shape of the solidified portion or the melting boundary 100 between the solidified portions 30 may not be observed in the solidified structure. .

As shown in FIG. 2 (b), the alloy structure 1 uses as main crystals columnar crystals in which non-Fe main component elements and Fe are solid-solved. In FIG. 2B, the cross section of the metallographic structure of the alloy structure is shown enlarged to a viewing angle of several hundred μm to several mm. Each crystal grain 50 contained in the metal structure of the alloy structure grows epitaxially with the crystal orientation substantially along the stacking direction of the solidified layer 40, and the grain boundary 110 (high angle grain boundary) is oriented in the stacking direction A structure is produced which extends beyond the melting boundary 100 between the solidified portions 30 while being oriented.

Each crystal grain 50 may be refined to an average crystal grain size of 10 μm or less. The refined crystal grains 50 maintain the crystal orientation, and the low angle grain boundary 120 may be observed inside the area divided into the high angle grain boundaries 110. The low angle grain boundary 120 is defined as a grain boundary with a tilt angle of 15 ° or less, and the high angle grain boundary 110 is defined as a grain boundary with a tilt angle of 15 ° or more. The refined crystal grains 50 tend to be an aggregation of crystal grains having a small twist angle as well as a tilt angle.

On the other hand, the conventional high entropy alloy material (the alloy material according to the comparative example) has a metal structure derived from the manufacturing method by casting. In the alloy material according to the comparative example, as shown in FIG. 2C, isotropically extending grain boundaries 110 are recognized, and coarse equiaxed crystal grains having an average crystal grain size exceeding 100 μm are formed. Tend. In FIG. 2C, the cross section of the metallographic structure of the alloy material is enlarged and shown at a viewing angle of several hundred μm to several mm. In the alloy material according to the comparative example, segregation is likely to occur as the nuclei grow, the uniformity of the composition distribution is lowered, or the crystal grains are coarse, so that the stress is difficult to be dispersed, and the surface causing cleavage or slip is long As a result, the mechanical strength is not sufficient. In particular, since the solid solution phase can not grow well, there is a problem that the size is small and a complicated shape can not be formed.

On the other hand, in the alloy structure according to the present embodiment, since crystals having relatively uniform crystal orientation are epitaxially grown, and consist of aggregates of crystal grains 50 grown favorably in the same environment, the alloy powder is adjusted The elemental composition thus obtained is easily maintained regardless of the shape and size of the alloy structure, and the uniformity of the composition distribution is enhanced. In addition, there is an advantage that the crystal grains 50 are miniaturized, strain due to stress is not easily concentrated locally, and the uniformity of mechanical strength is enhanced. Moreover, since the surface which produces cleavage and slip becomes short, it is advantageous at the point which mechanical strength improves. Furthermore, since the crystal growth direction is oriented and anisotropy is increased, it is also effective in using direction strength and magnetic characteristics.

Next, an example of the manufacturing method of the alloy powder used as an alloy structure raw material concerning this embodiment is demonstrated.

FIG. 3 is a schematic flow chart showing an example of a method of producing an alloy powder used as a raw material of an alloy structure.

As described above, the various properties of the alloy structure according to the present embodiment are likely to reflect the influence of the elemental composition of the alloy powder used in additive manufacturing. Therefore, it is preferable to make the alloy powder used as a raw material into an elemental composition in which the concentration of unavoidable impurities is reduced, and as a method of manufacturing the alloy powder, vacuum carbon deoxidation capable of manufacturing an alloy with high cleanliness. It is a preferable form to use a manufacturing method by complex refining using a method. The manufacturing method of the alloy powder shown in FIG. 3 is that the degree of cleanliness is improved by performing out-of-core refining using a ladle and using the crude metal as the raw metal for the composite smelting using a vacuum carbon deoxidation method. It is a method of refining a high alloy and preparing an alloy powder using the alloy, which is a method which can be applied as a process of preparing the above-mentioned alloy powder.

In this manufacturing method, as shown in FIG. 3A, first, the electric furnace 301 performs a melting process to melt the metal lump 302 of the rough metal which is a raw material of the alloy powder. In FIG. 3, the electric furnace 301 is a three-phase AC arc furnace including an electrode 304 such as a carbon electrode for generating arc discharge in the furnace and an oxygen burner 305 for blowing oxygen gas into the furnace. However, it is also possible to use a direct current arc furnace, a converter or the like having the same configuration.

As the metal mass 302, metal scraps, scrap metal, etc. can be used. It is preferable that the type of the metal mass 302 be blended so as to have an elemental composition compatible with the alloy powder to be manufactured, and that a type with few impurity elements be selected in advance. If it is not contained as a non-Fe main component, the kind should be selected so that the range is 0.005 wt% or less for Sn, 0.002 wt% or less for Sb, and 0.005 wt% or less for As. preferable.

In the melting process, as shown in FIG. 3A, the metal block 302 is placed in the furnace of the electric furnace 301, and an arc discharge 303 is generated between the electrode 304 and the metal block 302, thereby forming the metal block 302. Is melted and made into molten metal 310. Then, as shown in FIG. 3B, the oxygen gas 306 is blown into the molten metal 310 by the oxygen burner 305 to perform a peroxidation treatment to form a slag. By performing the peroxidation treatment by blowing oxygen into the molten metal 310 in this manner, impurity elements such as Si, Mn, and P contained in the molten metal 310 can be transferred as oxides into the slag. In addition, there is also an advantage that the amount of power for heating the molten metal 310 by the heat of combustion due to oxygen can be reduced.

After the slag is formed in the molten metal 310, the molten metal 310 is discharged from the outlet port 308 of the electric furnace 301 and transferred to the ladle 309 as shown in FIG. 3 (c). At this time, the slag containing a large amount of impurity elements floated on the liquid surface of the molten metal 310 separates the molten metal 310 and the slag so as not to transfer to the ladle 309, and the concentration of impurity elements such as Si, Mn, P etc. A reduced melt 310 is obtained.

Subsequently, as shown in FIG. 3D, the molten metal 310 is tapped from the bottom of the ladle 309 and transferred to the ladle refining furnace 311. The ladle smelting furnace 311 has a porous plug 313 at the bottom, and argon bubbling is performed by supplying argon gas 314 from the gas supply unit (not shown) into the furnace through the porous plug 313. There is. By performing argon bubbling, the molten metal 310 transferred to the ladle smelting furnace 311 is homogenized by stirring, and impurity elements such as O and N are degassed.

In the ladle refining furnace 311, as shown in FIG. 3 (e), first, the primary heat treatment of the molten metal 310 is performed. The molten metal 310 transferred to the ladle smelting furnace 311 is heated by generating an arc discharge with the electrode 304 and continuously performing bottom bubbling argon bubbling through the porous plug 313, thereby the elemental component and the temperature are reduced. It can be made uniform.

Subsequently, as shown in FIG. 3 (f), the molten metal 310 is degassed using a vacuum degassing apparatus 316. The inside of the vacuum degassing apparatus 316 is depressurized through an exhaust hole 317 to which a vacuum pump (not shown) is connected, and the molten metal 310 is sucked by moving relative to the ladle refining furnace 311 up and down. , And the apparatus for degassing the gas contained in the molten metal 310. Although FIG. 3 schematically shows a DH vacuum degassing furnace (Dortmund Hoerde type) having one immersion pipe as the vacuum degassing apparatus 316, the shroud without the immersion pipe is made of a ladle It may be in the form of covering the furnace 311, or it may be in the form of RH vacuum degassing furnace (Ruhrstahl Heraeus type) or RH injection furnace.

In the degassing process, the gas of the impurity element degassed from the molten metal 310 can be efficiently exhausted by performing argon bubbling while reducing the gas phase atmosphere in the apparatus by the vacuum degassing apparatus 316. it can. During the degassing process, the molten metal 310 is heated by a heater (not shown) to prevent a decrease in temperature, and a powder for desulfurization is appropriately injected into the molten metal 310. By subjecting the molten metal 310 to such a degassing treatment, the molten metal 310 in which the concentration of impurity elements such as S, O, H and the like is reduced can be obtained.

Subsequently, in the ladle refining furnace 311, as shown in FIG. 3 (g), the secondary heat treatment of the molten metal 310 is performed. In the secondary heat treatment, the elemental composition and temperature of the molten metal 310 are finally adjusted.

Subsequently, as shown in FIG. 3 (h), the molten metal 310 of the ladle refining furnace 311 is subjected to a casting process. The molten metal 310 is discharged from the bottom of the ladle refining furnace 311 and transferred to the tundish 318, and the impurity element is separated as slag in the tundish 318. Then, the molten metal 310 is poured from the bottom of the tundish 318 and poured into a mold 321 installed in the vacuum vessel 319. A vacuum pump (not shown) is connected to the vacuum vessel 319 via the exhaust hole 320 so that the inside of the vessel in which the mold 321 is installed is made into a reduced pressure atmosphere. Thus, when the molten metal 310 poured into the mold 321 is cooled, an alloy block 322 having an arbitrary shape is cast. By casting the molten metal 310 in a reduced pressure atmosphere, an alloy in which the concentration of impurity elements such as N, O and H is reduced can be obtained.

The alloy refined by the above method can be used as a metal for preparing an alloy powder used in a powder preparation process. The composite smelting using vacuum carbon deoxidation method results in an alloy with high purity in which the concentration of impurity elements is reduced, so that it is composed of particles with high uniformity of the elemental composition distribution, and the elemental composition between particles is The uniformity is also suitable for preparing an alloy powder with high uniformity. From the viewpoint of maintaining the cleanliness of the alloy refined in this manner, it is preferable to perform powdering treatment using a vacuum carbon deoxidation method when preparing the alloy powder.

The powderization process using a vacuum carbon deoxidation method can be performed using a vacuum furnace 324 to which a gas atomizer is directly connected as shown in FIG. 3 (i). The vacuum furnace 324 is an electric furnace provided with an electrode 304 for generating arc discharge in the furnace, a gas injection lance (not shown) for blowing argon gas into the furnace, and an exhaust hole (not shown) to which a vacuum pump is connected. Be done. At the bottom of the vacuum furnace 324, a nozzle 328 is provided, and below the nozzle 328, an atomizing chamber 330 is provided so as to airtightly cover the outlet of the nozzle 328. Further, at the outlet side of the nozzle 328, a gas injection hole 329 for blowing an inert gas such as argon gas to the molten metal 326 flowing down from the nozzle 328 is provided.

In the vacuum furnace 324, the alloy obtained by the complex refining described above is introduced into the furnace, and an arc discharge is generated between the electrode 304 and the alloy to form a molten metal 326 of the alloy. In addition, the temperature of the molten metal 326 heated is a temperature range which exceeds 1600 degreeC and is 2500 degrees C or less. The molten metal 326 is degassed while performing argon bubbling under a reduced pressure atmosphere by a vacuum pump connected to an exhaust hole (not shown), and the concentration of impurity elements such as N, O and H is further reduced. . Then, the molten metal 326 in a degassed state and in which the cleanliness is maintained flows downward from the nozzle 328. Thereafter, the molten metal 328 which has flowed down is atomized by spraying an inert gas jetted from the gas injection holes 329 and solidified in the atomizing chamber 330 to be a powder 331 and accumulated at the bottom.

The vacuum furnace 324 may be a heat-resistant and refractory heating furnace so as to melt a high entropy alloy having a relatively high melting point, and the furnace wall may be a water-cooled type or the like. As a furnace wall of the vacuum furnace 324, for example, graphite (graphite), quartz (SiO ₂ ), alumina (Al ₂ O ₃ ), magnesia (MgO), Al ₂ O ₃ · SiO ₂ · Fe ₂ O ₃ · Na ₂ Alumina-based ceramics consisting of mixed sintered bodies such as O, mullite-based ceramics consisting of mixed sintered bodies such as Al ₂ O ₃ · SiO ₂ · Fe ₂ O ₃ · TiO ₂ etc. Al ₂ O ₃ · MgO · SiO ₂ ··· magnesia ceramics consisting of a mixture sintered body such as _{_{CaO · Fe 2 O 3, Al}} 2 O 3 · MgO · ZrO 2 · SiO 2 · CaO · Fe 2 O 3 · TiO 2 zirconia comprising a mixed sintered body such as Ceramics, spinel-like ceramics composed of mixed sintered bodies of Al ₂ O ₃ · MgO · SiO ₂ · CaO · Fe ₂ O ₃ etc. Mixed sintered bodies of Al ₂ O ₃ · MgO · SiO ₂ · CaO · Fe ₂ O ₃ etc. Calculus consisting of a body It is preferred to apply the quality ceramics, siliceous ceramics consisting of _{_{_{Al 2 O 3 · SiO 2 ·}}} Fe 2 O 3 · TiO 2 mixed sintered body such as. In particular, in the case of melting at a high temperature of about 1000 ° C. or more, it is preferable to perform coating with carbides such as TiC, ZrC, HfC, NbC, TaC and the like.

FIG. 4 is a diagram showing an example of the change in concentration of impurity elements in an alloy powder prepared using a vacuum carbon deoxidation method.

In FIG. 4, in the process of refining the alloy using the above-mentioned vacuum carbon deoxidation method and pulverizing the alloy to prepare an alloy powder, the concentration change of the impurity element contained in the base metal of the alloy powder is Measured over time and shown. Period A corresponding to the elapsed time 1.5 h to 2.8 h corresponds to the peroxidation treatment (see FIG. 3B) in the electric furnace 301, and period B1 corresponding to the elapsed time 2.8 h to 6 h Degassing treatment in the ladle smelting furnace 311 (FIG. 3 (B), which corresponds to primary heat treatment in the ladle smelting furnace 311 (see FIG. 3 (e)) and corresponds to elapsed time 6 h to 6.5 h. The period B3 corresponding to f) and corresponding to the elapsed time 6.5 h to 8.2 h corresponds to the secondary heat treatment (see FIG. 3 (g)) in the ladle smelting furnace 311, and the elapsed time 8. The C period corresponding to 2 h or later corresponds to the degassing process (see FIG. 3I) in the vacuum furnace 324.

As shown in FIG. 4, when the secondary heat treatment is carried out in the ladle smelting furnace 311 by using a vacuum carbon deoxidation method, 0.18 wt% for C, 0.01 wt% for Si, and Mn for The concentration decreases to 0.019 wt% for P, 0.001 wt% for P, and 0.001 wt% for S, and when it is carried out to the degassing treatment in the vacuum furnace 324, 0.0003 wt% (3 ppm) for O, It can be seen that the concentration of N can be reduced to 0.001 wt% (10 ppm). As described above, P, Si, S, Sn, Sb, As, and the like can be appropriately adjusted by appropriately adjusting the number of times of slag separation, the time of degassing treatment, and the like in the process of preparing the alloy powder using the vacuum carbon deoxidation method. It is possible to limit the concentration of impurity elements such as Mn, O and N to a desired range. In addition, when the element of P, Si, Sn, Sb, As or Mn is contained in the alloy structure as a non-Fe main element, the metal is selected in anticipation of the concentration decrease in the refining process, or slag The number of separations may be adjusted as appropriate.

The alloy structure according to the present embodiment described above can be applied as a structural member, a mechanical member, and the like. The shape can be any shape within the layer-formable range, and the length dimension can exceed 70 mm and the volume can exceed 5495 mm ³ . It can be used for applications in severe environments such as high temperature environments, high radiation dose environments, and highly corrosive environments as well as applications in ordinary environments. In addition, since the rate of atomic diffusion at high temperatures is low and physical properties can be stably maintained, the invention can be suitably used for applications which are left in a high temperature environment for a long time. More specifically, it includes, for example, structural materials for plants including casings, pipes, valves, etc., structural materials for generators, structural materials for nuclear reactors, structural materials for aerospace, members for hydraulic equipment, turbine blades, etc. The present invention can be used for applications such as members for turbines, members for boilers, members for engines, members for nozzles, mechanical members for bearings, pistons, and the like. In addition, the alloy structure according to the present embodiment is applied so as to cover the surface of a structure made of metal or alloy, such as a structural member or a mechanical member, whereby a heat resistant coating, a corrosion resistant coating, a wear resistant coating, It can also be used as a diffusion barrier layer or the like that serves as a barrier to atomic diffusion. Moreover, it is applicable also to tools, such as a processing tool for friction stir welding (Friction Stir welding; FSW), and the wide use including friction stir welding of ferrous material which high high temperature strength and abrasion resistance are required for. It can be suitably used.

Hereinafter, the present invention will be described in more detail using examples of the present invention, but the technical scope of the present invention is not limited thereto.

As an example of the present invention, alloy structures according to Examples 1-1 to 1-4 and Examples 2-1 to 2-3 are manufactured, and observation of solidified structure, distribution of elemental composition, mechanical The characteristics were evaluated. In addition, as a control of the example, alloy structures according to Comparative Examples 1-1 to 1-4 and Comparative Examples 2-1 to 2-4 were manufactured and evaluated together.

Example 1-1
As Example 1-1, an alloy structure having an elemental composition represented by Al _0.3 CoCrFeNi was manufactured by lamination molding. The atomic concentration ratio is about 7 at% of Al and about 23.3 at% of Co, Cr, Fe, and Ni.

First, an alloy powder was prepared by gas atomization using an alloy having an atomic concentration of Al of about 7 at% and an atomic concentration of Co, Cr, Fe, and Ni of about 23.3 at% as a base metal. Then, the obtained alloy powder was classified, and the particle size distribution was limited to the range of 50 μm to 100 μm, and the volume-based average particle size was about 70 μm.

Subsequently, the layered structure forming apparatus was used to form an alloy structure on the substrate. A 100 mm × 100 mm × 10 mm plate-like carbon steel for machine structure “S45C” was used as a substrate. Moreover, as a lamination | stacking modeling apparatus, the electron beam fusion lamination molding apparatus "A2X" (made by Arcam) which made the heat source the electron beam was used. In the layered manufacturing apparatus, a cylindrical alloy structure having a diameter of 10 mm and a height of 50 mm was manufactured by repeatedly performing a powder spreading process and a solidified layer forming process on a base material in a vacuum atmosphere. At this time, melting of the alloy powder was performed while performing preliminary heating at a temperature of 50% to 80% of the melting point (Tm) of the alloy in advance to suppress scattering of the spread alloy powder. The alloy structure was then separated from the substrate.

Embodiment 1-2
As Example 1-2, an alloy structure having an elemental composition represented by AlCoCrFeNi was manufactured by lamination molding. The atomic concentration ratio is such that the atomic concentrations of Al, Co, Cr, Fe and Ni are about 20.0 at%.

The alloy structure according to Example 1-2 was manufactured in the same manner as Example 1-1 except that the composition of the base metal used to prepare the alloy powder was changed.

Comparative Example 1-1
As Comparative Example 1-1, an alloy structure having an elemental composition represented by Al _0.3 CoCrFeNi was manufactured by casting. The atomic concentration ratio is about 7 at% of Al and about 23.3 at% of Co, Cr, Fe, and Ni.

Subsequently, the obtained alloy powder is put into an alumina crucible, melted by high frequency induction heating in a vacuum atmosphere, poured into a water-cooled mold made of copper, cooled and solidified to obtain a diameter. A cylinder-shaped alloy structure of 10 mm and 50 mm in height was manufactured.

Comparative Example 1-2
As Comparative Example 1-2, an alloy structure having an elemental composition represented by Al _0.2 CoCrFeNi was manufactured by lamination molding. The atomic concentration ratio is about 4.8 at% for Al and about 23.8 at% for Co, Cr, Fe and Ni.

The alloy structure according to Comparative Example 1-2 was manufactured in the same manner as Example 1-1 except that the composition of the base metal used to prepare the alloy powder was changed.

Embodiment 1-3
As Example 1-3, an alloy structure having an elemental composition represented by Al _1.5 CoCrFeNi was manufactured by lamination molding. The atomic concentration ratio is such that the atomic concentration of Al is about 27.2 at%, and the atomic concentrations of Co, Cr, Fe and Ni are about 18.2 at%.

First, an alloy powder was prepared by gas atomization using an alloy having an atomic concentration of Al of about 27.2 at% and an atomic concentration of Co, Cr, Fe, and Ni of about 18.2 at% as a base metal. Then, the obtained alloy powder was classified, and the particle size distribution was limited to a range of 20 μm to 50 μm, and the volume-based average particle size was about 30 μm.

Subsequently, the laminate molding apparatus was used to model the alloy material on the base material. As a base material, carbon steel "S45C" for cylinder-like machine structure for diameter 10 mm and height 50 mm was used. Moreover, as a lamination | stacking modeling apparatus, the laser fusion lamination molding apparatus "EOSINT M270" (made by EOS company) which made the heat source the laser beam was used. In the lamination molding apparatus, a 200 μm multilayer film-like alloy material was manufactured by repeatedly performing the powder spreading process and the solidified layer forming process on the base material in a nitrogen atmosphere.

Comparative Example 1-3
As Comparative Example 1-3, an alloy structure having an elemental composition represented by AlCoCrFeNi was produced by thermal spraying. The atomic concentration ratio is such that the atomic concentrations of Al, Co, Cr, Fe and Ni are about 20.0 at%.

First, each metal powder of Al, Co, Cr, Fe and Ni was mixed such that the atomic concentration of Al, Co, Cr, Fe and Ni was about 20.0 at%. In addition, each metal powder was classified, and while limiting particle diameter distribution to the range of 50 micrometers or more and 150 micrometers or less, it was made for the average particle diameter on a volume basis to be about 70 micrometers.

Subsequently, the mixed metal powder was sprayed onto the base material by plasma spraying under a nitrogen atmosphere to produce a 200 μm film-like alloy structure. As a base material, carbon steel "S45C" for machine-structure-use cylindrical shape with a diameter of 100 mm and a height of 10 mm was used.

Comparative Example 1-4
As Comparative Example 1-4, an alloy structure having an elemental composition represented by Al _2.0 CoCrFeNi was manufactured by lamination molding. The atomic concentration ratio is such that the atomic concentration of Al is about 33.3 at%, and the atomic concentrations of Co, Cr, Fe, and Ni are about 16.7 at%.

The alloy structure according to Comparative Example 1-4 was manufactured in the same manner as Example 1-2 except that the composition of the base metal used for preparation of the alloy powder was changed.

Embodiment 1-4
As Example 1-4, an alloy structure whose elemental composition is represented by AlCoCrFeNiMo _0.5 was manufactured by lamination molding. The atomic concentration ratio is such that the atomic concentrations of Al, Co, Cr, Fe and Ni are about 18.2 at% and the atomic concentration of Mo is about 9.1 at%.

First, an alloy powder was prepared by gas atomization using an alloy having an atomic concentration of Al, Co, Cr, Fe and Ni of about 18.2 at% and an atomic concentration of Mo of about 9.1 at% as a base metal. . Then, the obtained alloy powder was classified, and the particle size distribution was limited to the range of 50 μm to 100 μm, and the volume-based average particle size was about 70 μm.

Subsequently, the layered structure forming apparatus was used to form an alloy structure on the substrate. As a base material, a cylindrical carbon steel for machine structure "S45C" with a diameter of 300 mm and a height of 10 mm was used. Moreover, as a lamination | stacking modeling apparatus, the electron beam fusion lamination molding apparatus "A2X" (made by Arcam) which made the heat source the electron beam was used. The layered molding apparatus manufactured a substantially cylindrical impeller-shaped alloy structure having a diameter of 300 mm and a height of 100 mm by repeatedly performing a powder spreading process and a solidified layer forming process on a base material in a vacuum atmosphere. . At this time, melting of the alloy powder was performed while performing preliminary heating at a temperature of 50% to 80% of the melting point (Tm) of the alloy in advance to suppress scattering of the spread alloy powder. Thereafter, the impeller-shaped alloy structure was separated from the substrate.

Example 2-1
As Example 2-1, an alloy structure represented by Al _0.3 CoCrFeNi and having a limited concentration of unavoidable impurities was manufactured by lamination molding. The atomic concentration ratio is about 7 at% of Al and about 23.3 at% of Co, Cr, Fe, and Ni. In addition, the concentration of P is 0.002 wt% or less, the concentration of Si is 0.010 wt% or less, the concentration of S is 0.001 wt% or less, the concentration of Sn is 0.002 wt% or less, the concentration of Sb is 0.001 wt% Hereinafter, the concentration of As was limited to 0.001 wt% or less, the concentration of Mn to 0.020 wt% or less, the concentration of O to 0.0003 wt% or less, and the concentration of N to 0.001 wt% or less.

The alloy structure according to Example 2-1 was manufactured in the same manner as Example 1-1 except that the composition of the base metal used for preparation of the alloy powder was changed.

Embodiment 2-2
As Example 2-2, an alloy structure having an elemental composition represented by AlCoCrFeNi and a limited concentration of unavoidable impurities was manufactured by lamination molding. The atomic concentration ratio is such that the atomic concentrations of Al, Co, Cr, Fe and Ni are about 20.0 at%. In addition, the concentration of P is 0.002 wt% or less, the concentration of Si is 0.010 wt% or less, the concentration of S is 0.001 wt% or less, the concentration of Sn is 0.002 wt% or less, the concentration of Sb is 0.001 wt% Hereinafter, the concentration of As was limited to 0.001 wt% or less, the concentration of Mn to 0.020 wt% or less, the concentration of O to 0.0003 wt% or less, and the concentration of N to 0.001 wt% or less.

The alloy structure according to Example 2-2 was manufactured in the same manner as Example 1-1 except that the composition of the base metal used for preparation of the alloy powder was changed.

Comparative Example 2-1
As Comparative Example 2-1, an alloy structure having an elemental composition represented by AlCoCrFeNi and a limited concentration of unavoidable impurities was manufactured by casting. The atomic concentration ratio is such that the atomic concentrations of Al, Co, Cr, Fe and Ni are about 20.0 at%. In addition, the concentration of P is 0.002 wt% or less, the concentration of Si is 0.010 wt% or less, the concentration of S is 0.001 wt% or less, the concentration of Sn is 0.002 wt% or less, the concentration of Sb is 0.001 wt% Hereinafter, the concentration of As was limited to 0.001 wt% or less, the concentration of Mn to 0.020 wt% or less, the concentration of O to 0.0003 wt% or less, and the concentration of N to 0.001 wt% or less.

The alloy structure according to Comparative Example 2-1 was manufactured in the same manner as Comparative Example 1-1 except that the composition of the base metal used for preparing the alloy powder was changed.

Comparative Example 2-2
As Comparative Example 2-2, an alloy structure having an elemental composition represented by Al _0.2 CoCrFeNi and having a limited concentration of unavoidable impurities was manufactured by casting. The atomic concentration ratio is about 4.8 at% for Al and about 23.8 at% for Co, Cr, Fe and Ni. In addition, the concentration of P is 0.002 wt% or less, the concentration of Si is 0.010 wt% or less, the concentration of S is 0.001 wt% or less, the concentration of Sn is 0.002 wt% or less, the concentration of Sb is 0.001 wt% Hereinafter, the concentration of As was limited to 0.001 wt% or less, the concentration of Mn to 0.020 wt% or less, the concentration of O to 0.0003 wt% or less, and the concentration of N to 0.001 wt% or less.

The alloy structure according to Comparative Example 2-2 was manufactured in the same manner as Example 1-1 except that the composition of the base metal used for preparation of the alloy powder was changed.

Example 2-3
As Example 2-3, an alloy structure represented by Al _1.5 CoCrFeNi and having a limited concentration of unavoidable impurities was manufactured by lamination molding. The atomic concentration ratio is such that the atomic concentration of Al is about 27.2 at%, and the atomic concentrations of Co, Cr, Fe and Ni are about 18.2 at%. In addition, the concentration of P is 0.005 wt% or less, the concentration of Si is 0.040 wt% or less, the concentration of S is 0.002 wt% or less, the concentration of Sn is 0.005 wt% or less, the concentration of Sb is 0.002 wt% Hereinafter, the concentration of As was limited to 0.005 wt% or less, the concentration of Mn to 0.050 wt% or less, the concentration of O to 0.001 wt% or less, and the concentration of N to 0.002 wt% or less.

First, the atomic concentration of Al is about 27.2 at%, the atomic concentrations of Co, Cr, Fe and Ni are about 18.2 at%, the concentration of P is 0.005 wt% or less, the concentration of Si is 0.040 wt% Hereinafter, the concentration of S is 0.002 wt% or less, the concentration of Sn is 0.005 wt% or less, the concentration of Sb is 0.002 wt% or less, the concentration of As is 0.005 wt% or less, the concentration of Mn is 0.050 wt% Hereinafter, an alloy powder was prepared by gas atomization using an alloy in which the concentration of O was limited to 0.001 wt% or less and the concentration of N to 0.002 wt% or less as a metal. Then, the obtained alloy powder was classified, and the particle size distribution was limited to a range of 20 μm to 50 μm, and the volume-based average particle size was about 30 μm.

Subsequently, the laminate molding apparatus was used to model the alloy material on the base material. As a base material, carbon steel "S45C" for machine-structure-use cylindrical shape with a diameter of 100 mm and a height of 10 mm was used. Moreover, as a lamination | stacking modeling apparatus, the laser fusion lamination molding apparatus "EOSINT M270" (made by EOS company) which made the heat source the laser beam was used. In the lamination molding apparatus, a 200 μm multilayer film-like alloy material was manufactured by repeatedly performing the powder spreading process and the solidified layer forming process on the base material in a nitrogen atmosphere.

Comparative Example 2-3
As Comparative Example 2-3, an alloy structure having an elemental composition represented by AlCoCrFeNi and a limited concentration of unavoidable impurities was manufactured by thermal spraying. The atomic concentration ratio is such that the atomic concentrations of Al, Co, Cr, Fe and Ni are about 20.0 at%. In addition, the concentration of P is 0.002 wt% or less, the concentration of Si is 0.010 wt% or less, the concentration of S is 0.001 wt% or less, the concentration of Sn is 0.002 wt% or less, the concentration of Sb is 0.001 wt% Hereinafter, the concentration of As was limited to 0.001 wt% or less, the concentration of Mn to 0.020 wt% or less, the concentration of O to 0.0003 wt% or less, and the concentration of N to 0.001 wt% or less.

First, the atomic concentration of Al, Co, Cr, Fe and Ni is about 20.0 at%, the concentration of P is 0.002 wt% or less, the concentration of Si is 0.010 wt% or less, the concentration of S is 0.001 wt% Hereinafter, the concentration of Sn is 0.002 wt% or less, the concentration of Sb is 0.001 wt% or less, the concentration of As is 0.001 wt% or less, the concentration of Mn is 0.020 wt% or less, the concentration of O is 0.0003 wt% Hereinafter, metal powders of Al, Co, Cr, Fe and Ni in which the concentration of N is limited to 0.001 wt% or less were mixed. In addition, each metal powder was classified, and while limiting particle diameter distribution to the range of 50 micrometers or more and 150 micrometers or less, it was made for the average particle diameter on a volume basis to be about 70 micrometers.

Comparative Example 2-4
As Comparative Example 2-4, an alloy structure in which the elemental composition was expressed as Al _2.0 CoCrFeNi and in which the concentration of unavoidable impurities was limited was manufactured by lamination molding. The atomic concentration ratio is such that the atomic concentration of Al is about 33.3 at%, and the atomic concentrations of Co, Cr, Fe, and Ni are about 16.7 at%. In addition, the concentration of P is 0.002 wt% or less, the concentration of Si is 0.010 wt% or less, the concentration of S is 0.001 wt% or less, the concentration of Sn is 0.002 wt% or less, the concentration of Sb is 0.001 wt% Hereinafter, the concentration of As was limited to 0.001 wt% or less, the concentration of Mn to 0.020 wt% or less, the concentration of O to 0.0003 wt% or less, and the concentration of N to 0.001 wt% or less.

The alloy structure according to Comparative Example 2-4 was manufactured in the same manner as Example 2-2 except that the composition of the base metal used for preparation of the alloy powder was changed.

Next, alloy structures according to Examples 1-1 to 1-4 and Examples 2-1 to 2-3 manufactured, and Comparative Examples 1-1 to 1-4 and Comparative Examples With respect to the alloy structures according to 2-1 to Comparative Example 2-4, observation of a solidified structure, analysis of a nickel concentration distribution, and hardness measurement were performed. The observation of the solidified structure was performed by confirming the crystal structure and the average crystal grain size with a high resolution transmission electron microscope. In addition, analysis of the nickel concentration distribution is carried out by using a scanning electron microscope-energy dispersive X-ray spectroscopy (energy dispersive X-ray detector; SEM-EDX) to measure the nickel concentration in 10 arbitrarily extracted regions. It did by measuring. The hardness was measured by measuring the Vickers hardness (Hv) of 10 arbitrarily extracted alloy materials. The test load was 100 gf and the holding time was 10 seconds.

The results of the observation of the solidified structure, the analysis of the nickel concentration distribution, and the hardness measurement are shown in Table 1. The column of element composition in Table 1 indicates the atomic concentration ratio of the main component element to the additive element. Also, in the column of impurities, “±” indicates an example in which the unavoidable impurities are not limited, an example in which “-” slightly restricts the inevitable impurities, and “-” indicates an example in which the inevitable impurities are more restricted. There is. The column of "Crystal structure" indicates the crystal structure of the main crystal. “*” In the “hardness” column indicates that a crack has occurred.

As shown in Table 1, the alloy structures according to Examples 1-1 to 1-4 and Examples 2-1 to 2-3 have the crystal structure or body-centered cubic lattice of the face-centered cubic lattice. It was confirmed to have any of the crystal structures of Further, it is understood from the values of the nickel concentration distribution and the hardness that the standard deviation is small and the uniformity of the distribution of the elemental composition and the mechanical strength is high. Further, from the observation of the solidified structure, a solidified structure and a crystal structure as shown in FIGS. 2 (a) and 2 (b) were confirmed. With respect to the alloy structure according to Example 1-4 having the impeller shape, it is separately confirmed that the amount of corrosion reduction at the time of a salt water (artificial seawater) corrosion test is suppressed more than that of austenitic stainless steel (SUS 304) It has also been confirmed that it is suitable as a corrosion resistant structural member, a corrosion resistant mechanical member and the like.

On the other hand, in the alloy structures according to Comparative Examples 1-1 to 1-4 and Comparative Examples 2-1 to 2-4, the values of the nickel concentration distribution and the hardness have a large standard deviation, and the elements It can be seen that the uniformity of the composition and the distribution of mechanical strength is low. In addition, it was recognized that the crystal structure reflects the low uniformity of the elemental composition, and a multiphase structure is formed. In particular, when the atomic concentration of Al is lowered, the hardness remains lower than that of mild steel, and it has been found that it is unsuitable as a structural member, a mechanical member or the like. In addition, when the atomic concentration of Al was increased, a B2 type intermetallic compound was formed, and a crack was generated at the time of the test, which proved to be unsuitable as a structural member, a mechanical member or the like.

Generally, in structural members, mechanical members, etc., thermal deterioration, wear, corrosion, etc. progress starting from the region with low resistance, so considering rolling etc., hardness and ductility are compatible in structural members, mechanical members, etc. Can be said to be desirable. Moreover, it can be said that the deviation of these properties is also required to be minimized. From such a viewpoint, the alloy structures according to Example 1-1 to Example 1-4 and Example 2-1 to Example 2-3 and Comparative Example 1-1 to Comparative Example 1-4 and Comparative Example From the results with the alloy structures according to 2-1 to Comparative Example 2-4, the uniformity of the distribution of the elemental composition and the mechanical strength according to the present invention significantly improves the characteristics of the structural member, the mechanical member, etc. It can be said that it has been confirmed that it works in an advantageous manner.

Next, as an example of the present invention, alloy structures according to Example 3-1 and Example 3-2 were manufactured, and stress-strain characteristics were evaluated.

FIG. 5 is a view showing the shape and dimensions of the alloy structure according to the third embodiment.

Example 3-1
As Example 3-1, an alloy structure shown in FIG. 5 in which the elemental composition is expressed as AlCoCrFeNi and the concentration of unavoidable impurities is limited was manufactured by lamination molding. The atomic concentration ratio is such that the atomic concentrations of Al, Co, Cr, Fe and Ni are about 20.0 at%. In addition, the concentration of P is 0.002 wt% or less, the concentration of Si is 0.010 wt% or less, the concentration of S is 0.001 wt% or less, the concentration of Sn is 0.002 wt% or less, the concentration of Sb is 0.001 wt% Hereinafter, the concentration of As was limited to 0.001 wt% or less, the concentration of Mn to 0.020 wt% or less, the concentration of O to 0.0003 wt% or less, and the concentration of N to 0.001 wt% or less.

First, the atomic concentration of Al is about 7 at%, the atomic concentrations of Co, Cr, Fe and Ni are about 23.3 at%, the concentration of P is 0.002 wt% or less, the concentration of Si is 0.010 wt% or less, The concentration of S is 0.001 wt% or less, the concentration of Sn is 0.002 wt% or less, the concentration of Sb is 0.001 wt% or less, the concentration of As is 0.001 wt% or less, the concentration of Mn is 0.020 wt% or less, An alloy powder was prepared by gas atomization using an alloy in which the concentration of O was limited to 0.0003 wt% or less and the concentration of N to 0.001 wt% or less as a metal. Then, the obtained alloy powder was classified, and the particle size distribution was limited to a range of 45 μm to 105 μm, and the volume-based average particle size was about 70 μm.

Subsequently, the laminate molding apparatus was used to model the alloy material on the base material. As a base material, a plate-like carbon steel for machine structure "S45C" of 200 mm × 200 mm × 10 mm was used. Moreover, as a lamination | stacking modeling apparatus, the electron beam fusion lamination molding apparatus "A2X" (made by Arcam) which made the heat source the electron beam was used. In the layered molding apparatus, a plate-shaped object of 150 mm × 150 mm × 30 mm (a plate-like structure (plate shape) as shown in FIG. 5 by repeatedly performing a powder spreading step and a solidified layer forming step on a substrate under a vacuum atmosphere. Part) were formed, and a total of 16 28 mm × 28 mm × 20 mm rectangular parallelepiped shaped objects (rectangular parallelepiped parts) were formed at intervals of 6 mm in length and width. At this time, melting of the alloy powder was carried out while performing preliminary heating at a temperature of 50% to 80% of the melting point (Tm) of the alloy powder in advance to suppress scattering of the spread alloy powder. In addition, the volume of the whole modeling thing was 925880 mm ³ .

Example 3-2
As Example 3-2, an alloy structure shown in FIG. 5 in which the elemental composition is represented by AlCoCrFeNi and the concentration of unavoidable impurities is not limited was manufactured by lamination molding. The atomic concentration ratio is such that the atomic concentrations of Al, Co, Cr, Fe and Ni are about 20.0 at%.

The alloy structure according to Example 3-2 was manufactured in the same manner as Example 3-1 except that the composition of the base metal used to prepare the alloy powder was changed. The concentration of unavoidable impurities in the alloy powder is 0.008 wt% of P, 0.040 wt% of Si, 0.012 wt% of S, and 0.006 wt% of Sn. The concentration was 0.002 wt%, the concentration of As was 0.006 wt%, the concentration of Mn was 0.300 wt%, the concentration of O was 0.002 wt%, and the concentration of N was 0.003 wt%.

Next, with respect to the manufactured alloy structures according to Example 3-1 and Example 3-2, analysis of nickel concentration distribution was performed. The analysis of nickel concentration distribution was arbitrarily extracted by a scanning electron microscope-energy dispersive X-ray detector (SEM-EDX) 10 for each of a total of 16 rectangular parallelepiped parts. It carried out by measuring nickel concentration about the field of a part. Table 2 shows the results of the average value and standard deviation of the Ni concentration distribution for a total of 16 rectangular parallelepiped parts.

As shown in Table 2, in the alloy structure according to Example 3-1 in which unavoidable impurities are further restricted, the deviation of the nickel concentration distribution for each rectangular parallelepiped portion is higher than the alloy structure according to Example 3-2. A smaller tendency appears, and it can be seen that the uniformity of the elemental composition distribution of the alloy structure is enhanced by further limiting the unavoidable impurities of the alloy powder.

Next, a test piece was extract | collected along the lamination direction about a total of 16 rectangular parallelepiped parts of the alloy structure shown in FIG. 5, and the uniaxial compression test was done. The test piece is a dumbbell-shaped test piece whose major axis is the stacking direction in the alloy structure, which is cut out from each rectangular parallelepiped portion to the plate-like portion, and the size of the parallel portion is 4 mm in diameter × 30 mm in height. It was. The measurement results of the compression true stress-compression true strain diagram at room temperature are shown in FIG. 6 as an average for a total of 16 rectangular portions.

FIG. 6 is a compression true stress-compression true strain diagram in the alloy structure according to the third embodiment.

As shown in FIG. 6, the variation of the true stress-true strain diagram is hardly recognized in any of Example 3-1 and Example 3-2, and the line width diagram shown in FIG. 6 is drawn. did it. That is, in the alloy structure having a volume about 160 times or more larger than that of the alloy material shown in Non-Patent Document 2, it has been confirmed that the uniformity of the mechanical characteristics is enhanced over the entire region of the shaped object. In particular, while the tensile strength is about 2800 MPa and the total elongation is about 38% in Example 3-2, the tensile strength is about 3850 MPa and the total elongation is about 43% in Example 3-1. It can be seen that the strength is about 1.37 times and the total elongation is about 1.1 times. Therefore, it is recognized that mechanical properties can be further improved by reducing the concentration of unavoidable impurities.

Next, as the examples of the present invention, the alloy structures according to Examples 4-1 to 4-3 were manufactured, and the tensile properties were evaluated.

Example 4-1
As Example 4-1, an alloy structure represented by AlCoCrFeNi and having a limited concentration of unavoidable impurities was manufactured by lamination molding. The atomic concentration ratio is such that the atomic concentrations of Al, Co, Cr, Fe and Ni are about 20.0 at%. In addition, the concentration of P is 0.002 wt% or less, the concentration of Si is 0.010 wt% or less, the concentration of S is 0.001 wt% or less, the concentration of Sn is 0.002 wt% or less, the concentration of Sb is 0.001 wt% Hereinafter, the concentration of As was limited to 0.001 wt% or less, the concentration of Mn to 0.020 wt% or less, the concentration of O to 0.0003 wt% or less, and the concentration of N to 0.001 wt% or less.

Subsequently, the layered structure forming apparatus was used to form an alloy structure on the substrate. As a base material, a plate-like carbon steel for machine structure "S45C" of 200 mm × 200 mm × 10 mm was used. Moreover, as a lamination | stacking modeling apparatus, the electron beam fusion lamination molding apparatus "A2X" (made by Arcam) which made the heat source the electron beam was used. In the layered forming apparatus, by repeatedly performing the powder spreading process and the solidified layer forming process on the base material in a vacuum atmosphere, the dumbbell-shaped test piece whose horizontal axis is the stacking direction of the solidified layer is formed as an alloy structure did. At this time, melting of the alloy powder was carried out while performing preliminary heating at a temperature of 50% to 80% of the melting point (Tm) of the alloy powder in advance to suppress scattering of the spread alloy powder. The dumbbell-shaped test piece was shaped in a state of being placed horizontally on the base together with the support member for supporting the test piece main body, and the parallel portion was made to have a diameter of 4 mm × height 30 mm.

Embodiment 4-2
As Example 4-2, an alloy structure having an elemental composition represented by AlCoCrFeNi and a limited concentration of unavoidable impurities was manufactured by lamination molding. The atomic concentration ratio is such that the atomic concentrations of Al, Co, Cr, Fe and Ni are about 20.0 at%. In addition, the concentration of P is 0.002 wt% to 0.005 wt%, the concentration of Si 0.010 wt% to 0.040 wt%, the concentration of S 0.001 wt% to 0.002 wt%, the concentration of Sn 0.. 002 wt% to 0.005 wt%, Sb concentration 0.001 wt% to 0.002 wt%, As concentration 0.001 wt% to 0.005 wt%, Mn concentration 0.020 wt% to 0.050 wt% The concentration of O was 0.0003 wt% to 0.001 wt%, and the concentration of N was 0.001 wt% to 0.002 wt%.

The alloy structure according to Example 4-2 was manufactured in the same manner as Example 4-1 except that the composition of the base metal used for preparation of the alloy powder was changed.

Example 4-3
As Example 4-3, an alloy structure represented by AlCoCrFeNi and not limiting the concentration of unavoidable impurities was manufactured by lamination molding. The atomic concentration ratio is such that the atomic concentrations of Al, Co, Cr, Fe and Ni are about 20.0 at%.

The alloy structure according to Example 4-3 was manufactured in the same manner as Example 4-1 except that the composition of the base metal used for preparation of the alloy powder was changed. The concentration of unavoidable impurities in the alloy powder is 0.008 wt% of P, 0.040 wt% of Si, 0.012 wt% of S, and 0.006 wt% of Sn. The concentration was 0.002 wt%, the concentration of As was 0.006 wt%, the concentration of Mn was 0.300 wt%, the concentration of O was 0.002 wt%, and the concentration of N was 0.003 wt%.

Next, a tensile test was conducted on the manufactured alloy structures according to Examples 4-1 to 4-3. The tensile test was conducted at a temperature of 0 ° C. to 900 ° C., and the tensile strength was measured. The measurement results of the tensile test are shown in FIG.

FIG. 7 is a view showing test temperature dependency of tensile strength in the alloy structure according to Example 4.

As shown in FIG. 7, in the alloy structures according to Examples 4-1 to 4-2 in which the unavoidable impurities are limited, the alloy structures according to Example 4-3 in which the unavoidable impurities are not limited. On the other hand, it can be seen that the tensile strength is improved. Further, it is understood that in the alloy structure according to Example 4-1 in which unavoidable impurities are further restricted, the tensile strength is improved in a wide temperature range. Therefore, it has been confirmed that it is effective to further improve the mechanical characteristics by reducing the concentration of unavoidable impurities.

Next, as an example of the present invention, the alloy structure according to Example 5, Example 6, Example 7, and Example 8 was manufactured by changing the kind of the main component element, and the evaluation was performed.

First, it was estimated by thermodynamic calculation whether or not it is possible to form a solid phase of a high entropy alloy with iron (Fe) and other plural elements as main components. In addition, thermodynamic calculation is performed using the first principle calculation method on the assumption that the case of containing five or more kinds of elements including Fe in an elemental composition that is an equiatomic ratio, and in such an elemental composition It was confirmed whether a solid solution phase could be formed at normal temperature and normal pressure. A plurality of elements of the main component were selected from the element group of atomic number 3 to atomic number 83 contained in Groups 3 to 16 of the periodic table of elements in addition to Fe.

FIG. 8 is a diagram showing the range of main component elements capable of forming a solid solution phase in the alloy structure.

In FIG. 8, the vertical axis indicates the atomic number of the element, and the horizontal axis indicates the ratio of atomic radius to Fe atom (atomic radius of each element / atomic radius of Fe). Moreover, the shape of each plot has shown the crystal structure in normal temperature and a normal pressure. Double squares are face-centered cubic lattices, double circles are body-centered cubic lattices, hexagons are hexagonal close-packed, and squares are other crystal lattices.

When thermodynamic calculation is performed for various combinations of elements of the main component, it is possible to form a solid solution phase for an element composition containing the elements in the region surrounded by a dashed line in FIG. It turned out to be. Specifically, an element (non-Fe main component element) which is recognized to be able to form a solution together with Fe has a ratio of atomic radius to Fe atom from Al of atomic number 13 to Au of atomic number 79. Is an element of 0.83 or more and 1.17 or less, that is, Al, Si, P, Ti, V, Cr, Mn, Co, Ni, Cu, Zn, Ga, Ge, As, Se, Nb, Mo, Tc , Ru, Rh, Pd, Ag, Sn, Sb, Te, Ta, W, Re, Os, Ir, Pt, Au. As the component composition according to the combination, CoCrFeNiAl, CoCrFeNiCu, CoCrFeNiCuAl, CoCrFeNiCuAlSi, MnCrFeNiCuAl, CoCrFeNiMnGe, CoCrFeNiMn, CoCrFeNiMnCu, TiCoCrFeNiCuAlV, TiCoCrFeNiAl, AlTiCoCrFeNiCuVMn, TiCrFeNiCuAl, TiCoCrFeNiCuAl, CoCrFeNiCuAlV, TiCoCrFeNiAl, TiCoCrFeNiCuAl, CoCrFeNiCuAl, CoFeNiCuV, CoCrFeNiCuAl, MnCrFeNiAl, MoCrFeNiCu, TiCoCrFeNi, TiCoCrFeNiMo, CoCrFeNiCuAlV, nCrFeNiCu, TiCoCrFeNi, TiCoCrFeNiAl, CoCrFeNiMo, CoCrFeNiAlMo, TiCoCrFeNiCu, CoCrFeNiCuAlMn, TiCoCrFeNiMo, CoCrFeNiCuAlV, TiCoCrFeNiCuVMn, AlTiCoCrFeNiCuVMn, CoCrFeNiCuAlMn, CoCrFeNiAlMo, CoCrFeNiCuAlMo, TiCoCrFeNiCu, etc. was confirmed. Among these, a nine-element high-entropy alloy of AlTiCoCrFeNiCuVMn was applied to shaping of the alloy structure according to Example 5, Example 6, Example 7, and Example 8.

[Example 5]
As Example 5, an alloy structure shown in FIG. 5 in which the elemental composition was AlTiCoCrFeNiCuVMn and the concentration of unavoidable impurities was limited was manufactured by lamination molding. The atomic concentration ratio was made to be a substantially equiatomic ratio by arranging the atomic concentration difference within ± 3% for atomic concentrations of Al, Ti, Co, Cr, Fe, Ni, Cu, V and Mn. In addition, the concentration of P is 0.005 wt% to 0.002 wt%, the concentration of Si is 0.040 wt% to 0.010 wt%, the concentration of S is 0.002 wt% to 0.001 wt%, and the concentration of Sn is 0.1. 005 wt% to 0.002 wt%, Sb concentration 0.002 wt% to 0.001 wt%, As concentration 0.005 wt% to 0.001 wt%, Mn concentration 0.050 wt% to 0.020 wt%, The concentration of O was limited to 0.001 wt% to 0.0003 wt%, and the concentration of N was limited to 0.002 wt% to 0.001 wt%.

First, the atomic concentrations of Al, Ti, Co, Cr, Fe, Ni, Cu, V and Mn are approximately equiatomic ratio, the concentration of P is 0.002 wt% or less, the concentration of Si is 0.010 wt% or less , S concentration of 0.001 wt% or less, Sn concentration of 0.002 wt% or less, Sb concentration of 0.001 wt% or less, As concentration of 0.001 wt% or less, Mn concentration of 0.020 wt% or less An alloy powder was prepared by gas atomization using an alloy in which the concentration of O is limited to 0.0003 wt% or less and the concentration of N to 0.001 wt% or less as a metal. Then, the obtained alloy powder was classified, and the particle size distribution was limited to a range of 45 μm to 105 μm, and the volume-based average particle size was about 70 μm.

Subsequently, the laminate molding apparatus was used to model the alloy material on the base material. As a base material, a plate-like carbon steel for machine structure "S45C" of 200 mm × 200 mm × 10 mm was used. Moreover, as a lamination | stacking modeling apparatus, the electron beam fusion lamination molding apparatus "A2X" (made by Arcam) which made the heat source the electron beam was used. In the layer-forming apparatus, it was shaped by repeatedly performing the powder spreading process and the solidified layer forming process on the base material in a vacuum atmosphere. At this time, melting of the alloy powder was carried out while performing preliminary heating at a temperature of 50% to 80% of the melting point (Tm) of the alloy powder in advance to suppress scattering of the spread alloy powder. The manufactured alloy structure according to Example 5 had substantially the same shape as the alloy structure shown in FIG. 5, and the volume of the entire ^three- dimensional object was 856,700 mm ³ .

Next, a test piece was extract | collected along the lamination direction about a total of 16 rectangular parallelepiped parts of the alloy structure which concerns on Example 5, and the uniaxial compression test was done. The test piece is a dumbbell-shaped test piece whose major axis is the stacking direction in the alloy structure, which is cut out from each rectangular parallelepiped portion to the plate-like portion, and the size of the parallel portion is 8 mm in diameter × 12 mm in height. It was. Further, with respect to the manufactured alloy structure according to Example 5, analysis of the Fe concentration distribution was performed. The analysis of the Fe concentration distribution was performed by measuring the iron concentration in 10 arbitrarily extracted regions by scanning electron microscopy-energy dispersive X-ray spectroscopy for a total of 16 rectangular parallelepiped portions.

As a result, it was confirmed that in the average for each rectangular parallelepiped part, the variation of the true stress-true strain diagram and the Fe concentration distribution were both within the range of a difference of 1 to 3% or less. In addition, it was confirmed that the standard deviation was 1.20% or less, and the uniformity of the distribution of the elemental composition was enhanced. Further, the elemental composition of the alloy structure according to Example 5 is substantially the same as the elemental composition of the used alloy powder, and the error of the component concentration is within about ± 3%, and the elemental composition distribution, melting rate, cooling It was confirmed that the unevenness due to the speed and the like is eliminated and the uniformity of the distribution of the elemental composition and the mechanical strength can be secured.

[Example 6]
In Example 6, an alloy structure (see FIG. 9) having an arc-like shape in which the elemental composition was AlTiCoCrFeNiCuVMn and the concentration of unavoidable impurities was limited was manufactured by lamination molding.

FIG. 9 is a view showing the shape and dimensions of the alloy structure according to the sixth embodiment.

As shown in FIG. 9, the alloy structural body 1A according to the sixth embodiment is a columnar body having a circular arc-shaped cross section, and has a shape that can be applied to a turbine blade or the like. The alloy structure 1A having such a shape is manufactured in the same manner as in Example 5 except that the three-dimensional shape to be laminated and formed is changed, and the width (W) 149 mm x depth (D) 110 mm x height (height) H) It modeled as a 153 mm arc-shaped object. The manufactured alloy structure according to Example 6 has a volume of 184480 mm ³ and a surface area of 60470 mm ² , and has a volume of about 33 times the volume of the alloy material shown in Non-Patent Document 2 and having a volume of 184480 mm ³ . It was possible.

Next, with respect to the alloy structure according to Example 6, analysis of the Fe concentration distribution was performed. The analysis of the Fe concentration distribution was performed by measuring the iron concentration in 10 arbitrarily extracted regions by scanning electron microscopy-energy dispersive X-ray spectroscopy.

As a result, the elemental composition of the alloy structure according to Example 6 is substantially the same as the elemental composition of the used alloy powder, and the error of the component concentration is within about ± 3%, the elemental composition distribution, the melting rate, It has been confirmed that the unevenness due to the cooling rate etc. is eliminated and also the uniformity of the distribution of the elemental composition and the mechanical strength can be secured.

[Example 7]
As Example 7, an alloy structure having an elemental composition of AlTiCoCrFeNiCuVMn and a dumbbell-like shape in which the concentration of unavoidable impurities is limited was manufactured by lamination molding.

The alloy structure according to Example 7 is manufactured and solidified in the same manner as in Example 4-1 except that the composition of the base metal used for preparation of the alloy powder and the three-dimensional shape to be layered are changed. It was set as the dumbbell-shaped shaped article which makes the lamination direction of a layer a horizontal axis.

As a result, the elemental composition of the alloy structure according to Example 7 is substantially the same as the elemental composition of the used alloy powder, and the error of the component concentration is within about ± 3%, the elemental composition distribution, the melting rate, It has been confirmed that the unevenness due to the cooling rate etc. is eliminated and also the uniformity of the distribution of the elemental composition and the mechanical strength can be secured. In addition, compared to the alloy structure according to Example 4-1, it is confirmed that the surface is smooth and the metallic gloss is strongly developed, and the surface characteristics are improved by dividing the element composition of the alloy structure. It was found that the effect of reforming was obtained.

[Example 8]
As Example 8, an alloy structure having an elemental composition of AlTiCoCrFeNiCuVMn and a rod-like shape in which the concentration of unavoidable impurities is limited was manufactured by lamination molding.

The alloy structure according to Example 8 was shaped in the same manner as Example 4-1 except that the composition of the base metal used for preparation of the alloy powder and the three-dimensional shape to be layered and formed were changed.

As a result, the elemental composition of the alloy structure according to Example 8 is substantially the same as the elemental composition of the used alloy powder, and the error of the component concentration is within about ± 3%, the elemental composition distribution, the melting rate, It has been confirmed that the unevenness due to the cooling rate etc. is eliminated and also the uniformity of the distribution of the elemental composition and the mechanical strength can be secured. Using the manufactured alloy structure according to Example 8 as a friction stir tool, friction stir welding was performed on a soft iron plate having a thickness of 10 mm or less. As a result, it was possible to join without causing a defect in the joining portion, and it was possible to perform good joining with almost no warping. That is, it is confirmed that the alloy structure according to the example 8 which is diversified is applicable to the friction stir welding of a material mainly composed of Fe, which is required to have high temperature strength and wear resistance, and which was conventionally difficult. The In addition, in the solidified layer forming step, a shaped object appropriately processed is obtained by performing shape forming processing and surface processing of the solidified portion or the solidified layer in a high temperature state until the solidified portion is formed. It was also confirmed that it was possible.

DESCRIPTION OF SYMBOLS 1 alloy structure 10 alloy powder 15 base material 20 melting part 21 base material mounting table 22 processing table 23 recoater 24 heating means 30 solidification part 40 solidification layer 50 crystal grain 100 melting boundary 110 grain boundary (high angle angle grain boundary)
120 small angle grain boundary 301 electric furnace 302 metal lump 303 arc discharge 304 electrode 305 oxygen burner 306 oxygen gas 309 ladle 310 molten metal 311 ladle smelting furnace 313 porous plug 314 argon gas 316 vacuum device 317 exhaust hole 318 tundish 319 vacuum Container 320 Exhaust hole 324 Electric furnace 326 Molten metal 330 chamber

Claims

A melting step of melting a raw metal block to form a molten metal;
A peroxidation step of blowing oxygen gas into the molten metal to form a slag;
A separation step of separating the molten metal and the slag raised to the liquid surface of the molten metal;
A degassing step of degassing gas components in the molten metal by blowing argon gas into the molten metal separated from the slag;
A casting step of casting the deaerated molten metal to form a cast alloy,
The cast alloy is
Melting the cast alloy in vacuum to form a molten alloy;
Pulverizing the molten alloy by flowing down the molten alloy and blowing an inert gas onto the flowing molten alloy to form an alloy powder;
A powder spreading step of spreading the alloy powder in layers;
The spread alloy powder is locally heated and melted and then solidified to form a solidified structure, and the heated region by the local heating is moved parallel to the surface on which the alloy powder is spread A solidified layer forming step of forming a solidified layer;
It is used in a series of steps of forming a plurality of layer solidified layers by alternately repeating the powder spreading step and the solidified layer forming step,
The cast alloy contains five elements of Al, Co, Cr, Fe and Ni,
As inevitable impurities, P is not more than 0.005 wt%, Si is not more than 0.040 wt%, S is not more than 0.002 wt%, Sn is not more than 0.005 wt%, Sb is not more than 0.002 wt%, As is not more than 0.005 wt% % Or less, Mn at 0.050 wt% or less, O at 0.001 wt% or less, and N at an atomic concentration range of 0.002 wt% or less.
As the unavoidable impurities, P is 0.002 wt% or more and 0.005 wt% or less, Si is 0.010 wt% or more and 0.040 wt% or less, S is 0.001 wt% or more and 0.002 wt% or less, and Sn is 0.002 wt% % To 0.005 wt%, Sb 0.001 wt% to 0.002 wt%, As As 0.001 wt% to 0.005 wt%, Mn 0.020 wt% to 0.050 wt%, O 0 The method for producing a cast alloy according to claim 1, wherein the alloy contains 0003 wt% or more and 0.001 wt% or less and N in an atomic concentration range of 0.001 wt% or more and 0.002 wt% or less.
As the unavoidable impurities, P is not more than 0.002 wt%, Si is not more than 0.005 wt%, S is not more than 0.001 wt%, Sn is not more than 0.002 wt%, Sb is not more than 0.001 wt%, As is 0. The cast alloy according to claim 1, which contains 001 wt% or less, Mn at 0.005 wt% or less, O at 0.0003 wt% or less, and N at an atomic concentration of 0.001 wt% or less. Method.
The method for producing a cast alloy according to claim 1, wherein the alloy contains each of the five elements in an atomic concentration range of 5 at% to 30 at%.
The method for producing an alloy structure according to claim 4, wherein the alloy has a difference in atomic concentration of at least four of the five elements within a range of less than 3 at%.
The alloy contains at least four elements of Al, Co, Cr, Fe, and Ni in an atomic concentration range of 15 at% or more and 23.75 at% or less, and 5 at% of one other element. The method for producing a cast alloy according to claim 1, wherein the alloy is contained in an atomic concentration range of 30 at% or less.
A melting step of melting a raw metal block to form a molten metal;
A peroxidation step of blowing oxygen gas into the molten metal to form a slag;
A separation step of separating the molten metal and the slag raised to the liquid surface of the molten metal;
A degassing step of degassing gas components in the molten metal by blowing argon gas into the molten metal separated from the slag;
A casting step of casting the deaerated molten metal to form a cast alloy,
The cast alloy is
Melting the cast alloy in vacuum to form a molten alloy;
Pulverizing the molten alloy by flowing down the molten alloy and blowing an inert gas onto the flowing molten alloy to form an alloy powder;
A powder spreading step of spreading the alloy powder in layers;
The spread alloy powder is locally heated and melted and then solidified to form a solidified structure, and the heated region by the local heating is moved parallel to the surface on which the alloy powder is spread A solidified layer forming step of forming a solidified layer;
It is used in a series of steps of forming a plurality of layer solidified layers by alternately repeating the powder spreading step and the solidified layer forming step,
The cast alloy is selected from the element group of atomic number 13 to atomic number 79 contained in Groups 3 to 16 of the periodic table of elements, and the ratio of atomic radius to Fe atom is 0.83 to 1.17. Containing at least four elements that are
As inevitable impurities, P is not more than 0.005 wt%, Si is not more than 0.040 wt%, S is not more than 0.002 wt%, Sn is not more than 0.005 wt%, Sb is not more than 0.002 wt%, As is not more than 0.005 wt% % Or less, Mn at 0.050 wt% or less, O at 0.001 wt% or less, and N at an atomic concentration range of 0.002 wt% or less.
As the unavoidable impurities, P is 0.002 wt% or more and 0.005 wt% or less, Si is 0.010 wt% or more and 0.040 wt% or less, S is 0.001 wt% or more and 0.002 wt% or less, and Sn is 0.002 wt% % To 0.005 wt%, Sb 0.001 wt% to 0.002 wt%, As As 0.001 wt% to 0.005 wt%, Mn 0.020 wt% to 0.050 wt%, O 0 The method for producing a cast alloy according to claim 7, characterized in that it contains .0003 wt% or more and 0.001 wt% or less and N in an atomic concentration range of 0.001 wt% or more and 0.002 wt% or less.
As the unavoidable impurities, P is not more than 0.002 wt%, Si is not more than 0.005 wt%, S is not more than 0.001 wt%, Sn is not more than 0.002 wt%, Sb is not more than 0.001 wt%, As is 0. The cast alloy according to claim 7, which contains 001 wt% or less, Mn at 0.005 wt% or less, O at 0.0003 wt% or less, and N at an atomic concentration of 0.001 wt% or less. Method.
The at least four elements are Al, Si, P, Ti, V, Cr, Mn, Co, Ni, Cu, Zn, Ga, Ge, As, Se, Nb, Mo, Tc, Ru, Rh, Pd, The method for producing a cast alloy according to claim 7, characterized in that it is selected from the group consisting of Ag, Sn, Sb, Te, Ta, W, Re, Os, Ir, Pt and Au.
The method for producing a cast alloy according to claim 1, wherein the alloy contains each of the five elements in an atomic concentration range of 5 at% to 30 at%.
The method according to claim 11, wherein in the alloy, the difference in atomic concentration of at least four of the five elements is less than 3 at%.