Copper alloy deposition model and method for producing copper alloy deposition model

Abstract

This copper alloy deposition model is formed of a Cu-Cr-Ni-Si-based alloy, the Cu-Cr-Ni-Si-based alloy having a Cr content within the range of 0.1-0.8 mass%, a Si content within the range of 0.4-0.8 mass%, and a Ni content within the range of 1.8-3.0 mass%. The model density is 99.5% or more, and the area ratio of a crystal having a plane orientation of (101) ± 15° in a specific direction is 51% or more as determined by crystal orientation measurement by means of electron backscattered diffraction.

Description

Copper alloy laminated body and method for manufacturing copper alloy laminated body

[0001] The present invention relates to a copper alloy additive manufacturing method and a copper alloy additive manufacturing method for a Cu-Cr-Ni-Si alloy. This application claims priority to Japanese Patent Application No. 2024-069827, filed on April 23, 2024, the contents of which are incorporated herein by reference.

[0002] In recent years, metal additive manufacturing (metal AM) technology has been put into practical use as a method for manufacturing metal parts with various three-dimensional shapes. This technology primarily uses powder as a raw material and creates products using a metal 3D printer. Major metal AM technologies using metal powder include powder bed fusion (PBF), directed energy deposition (DED), and binder jetting, which use electron beams or laser light. Copper alloys possess many fundamental properties suitable for industrial applications, such as electrical conductivity, thermal conductivity, mechanical properties, wear resistance, and heat resistance, and are used as materials for various components. For example, Cu-Cr-Ni-Si alloys (e.g., CDA No. C18000), a type of precipitation-hardened copper alloy, have excellent electrical conductivity and strength and are widely used as materials for various components. Therefore, in recent years, attempts have been made in various fields, such as space and electrical component applications, to form components of various shapes using metal AM using copper alloy powder, and there is a growing need for copper and copper alloy components manufactured using metal AM.

[0003] For example, Patent Document 1 proposes a technique for producing an additive manufacturing object by metal AM using a copper alloy powder containing either Cr or Si. Patent Document 2 and Non-Patent Document 1 also propose techniques for producing an additive manufacturing object by metal AM using a copper alloy powder containing Cr and Zr.

[0004] JP 2016-211062 A JP 2019-070169 A

[0005] Bruno Buchmayr et. al., "Laser Powder Bed Fusion- Materials Issues and Optimized Processing Parameters for Tool steels, AlSiMg- and CuCrZr-Alloys", ADVANCED ENGINEERING MATERIALS 2017, 19, No. 4, 1600667.

[0006] Because additive manufacturing (AM) products manufactured by metal AM are used as structural components for a variety of applications, the presence of voids in copper alloy AM products or an inhomogeneous microstructure as a metal material poses problems in terms of thermomechanical and electrical reliability. Currently, the most commonly used manufacturing method for metal AM is laser PBF, and attempts have been made to use it for manufacturing copper and copper alloys.

[0007] When performing additive manufacturing using laser or electron beam irradiation, a thin powder layer is first formed (powder bed), and then the powder bed is locally irradiated with a laser or electron beam to melt and solidify the material. However, copper and copper alloys have a high reflectivity in the visible and infrared regions compared to other metal materials such as iron, titanium, and nickel. This causes unstable melting behavior of copper alloy powder during laser PBF, which tends to generate voids inside the produced additively manufactured object, resulting in a number of issues such as unstable quality of the manufactured object and poor productivity. Therefore, there is a need for improvements in the productivity and quality of copper alloy additively manufactured objects made of copper and copper alloys by laser PBF.

[0008] Furthermore, in copper alloy members made of copper alloys, the properties required of the product vary depending on the intended use, and therefore anisotropy of the mechanical properties may be required depending on the intended use. Here, in conventional copper alloy members, the anisotropy of the mechanical properties was imparted by controlling the crystal orientation of the copper alloy material by adjusting the conditions for plastic processing, such as rolling and extrusion, and the conditions for heat treatment. In copper alloy members made of the above-mentioned copper alloy additive manufacturing product, since they are formed into a shape similar to the final product, it is desired to control the anisotropy of the mechanical properties without performing the above-mentioned plastic processing, such as rolling and extrusion.

[0009] The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide a copper alloy additive manufacturing body made of a Cu-Cr-Ni-Si alloy, which has few structural defects such as voids and has a high degree of crystal orientation.

[0010] In order to solve the above-mentioned problems, the present inventors conducted extensive research and found that when a high-purity copper alloy is used as a raw material and subjected to a powdering process, the copper alloy powder as a whole has few impurities and maintains a uniform composition, but when focusing on the surfaces of individual particles in the copper alloy powder, a thin layer is formed on the surface of the copper alloy particles that are irradiated with a laser.The thin layer formed on the surface of the copper alloy particles has a characteristic structure in which, compared to the interior of the bulk copper alloy particles, powder constituent elements that exhibit higher laser absorption than copper are present at a high frequency.The thin layer formed on the surface of the copper alloy particles has a characteristic structure which is spontaneously generated in the direct powdering process from the copper alloy raw material, without undergoing a separate coating process or additional process on the powder.

[0011] In addition to the structural characteristics of the copper alloy particle surfaces of such copper alloy powders, the copper alloy powders derived from high-purity copper alloy raw materials contain fewer impurities that lead to degassing components, thereby suppressing degassing during melting. It has been discovered that this enables the production of dense copper alloy additive manufacturing objects while maintaining high thermal, electrical, and mechanical properties. Specifically, it has been found that when copper alloy powder (Cu-Cr-Ni-Si-based alloy particles) is produced using a copper alloy ingot containing Cr, Ni, and Si with sufficiently reduced impurity levels as a raw material, CrSi-based compounds precipitate uniformly at the copper crystal grain boundaries of the copper alloy particles that make up the powder. It has also been discovered that the occurrence of structural defects such as voids can be reduced when this powder is used for additive manufacturing.

[0012] Furthermore, when using the above-mentioned copper alloy powder to manufacture a copper alloy additive manufacturing object by irradiating a specific region of a raw material with laser light, it has been discovered that increasing the energy density of the irradiated laser light suppresses the occurrence of defects such as voids, thereby promoting the formation of a continuous structure and enabling a specific crystal orientation to be strongly oriented in the stacking direction. Although laser light is used as the energy source for manufacturing in this invention, it is believed that similar results will be observed when other energy sources are used.

[0013] The present invention has been made based on the above-mentioned findings, and a copper alloy additive manufacturing object of Aspect 1 of the present invention is a copper alloy additive manufacturing object made of a Cu-Cr-Ni-Si-based alloy, wherein the Cu-Cr-Ni-Si-based alloy has a Cr content in the range of 0.1 mass % or more and 0.8 mass % or less, a Si content in the range of 0.4 mass % or more and 0.8 mass % or less, and a Ni content in the range of 1.8 mass % or more and 3.0 mass % or less, the Cu-Cr-Ni-Si-based alloy has a density of 99.5% or more, and as a result of crystal orientation measurement by electron backscatter diffraction, the area ratio of crystals having a plane orientation of {101}±15° in a specific direction is 51% or more.

[0014] According to the copper alloy additive manufacturing body of aspect 1 of the present invention, the copper alloy additive manufacturing body is composed of a Cu-Cr-Ni-Si alloy having a Cr content in the range of 0.1 mass% or more and 0.8 mass% or less, a Si content in the range of 0.4 mass% or more and 0.8 mass% or less, and a Ni content in the range of 1.8 mass% or more and 3.0 mass% or less. Therefore, the copper alloy additive manufacturing body has excellent conductivity and strength, and can be widely used as a material for various parts.

[0015] Furthermore, since the density of the copper alloy additive manufacturing product is 99.5% or more, structural defects such as voids are few, resulting in excellent quality. In this specification, the term "molded body density" refers to the packing density in the cross section of the copper alloy additive manufacturing product, calculated from the cross-sectional area of ​​the copper alloy additive manufacturing product and the area occupied by voids observed in the cross section of the copper alloy additive manufacturing product. Furthermore, as a result of measuring the crystal orientation using electron backscatter diffraction, the area ratio of crystals having a plane orientation of {101}±15° in a specific direction is 51% or more, which means that the crystal orientation is highly oriented, and the material has sufficient anisotropy in mechanical properties compared to the same material with random orientation.

[0016] Aspect 2 of the present invention is characterized in that the oxygen concentration is 80 ppm by mass or less in the copper alloy additive manufacturing product of Aspect 1. According to the copper alloy additive manufacturing product of Aspect 2 of the present invention, the oxygen concentration is suppressed to 80 ppm by mass or less, and therefore structural defects such as voids caused by oxygen are further reduced, the electrical conductivity is excellent, and the quality is excellent.

[0017] Aspect 3 of the present invention is characterized in that the copper alloy additive manufacturing product of Aspect 1 or Aspect 2 has an electrical conductivity of 20% IACS or more. The copper alloy additive manufacturing product of Aspect 3 of the present invention is a Cu-Cr-Ni-Si-based alloy having a Cr content in the range of 0.1% by mass to 0.8% by mass, a Si content in the range of 0.4% by mass to 0.8% by mass, and a Ni content in the range of 1.8% by mass to 3.0% by mass, and has an electrical conductivity of 20% IACS or more, making it suitable for use as a conductive member.

[0018] A fourth aspect of the present invention is characterized in that the sulfur concentration is 8 ppm by mass or less in the copper alloy additive manufacturing product of Aspect 1. Since the sulfur concentration is suppressed to 8 ppm by mass or less in the copper alloy additive manufacturing product of Aspect 4 of the present invention, structural defects such as sulfur-induced voids are further reduced, electrical conductivity is excellent, and quality is excellent.

[0019] Aspect 5 of the present invention is a method for producing a copper alloy additive manufacturing object according to any one of Aspects 1 to 4, characterized in that it comprises the steps of: preparing a copper alloy powder for metal AM; forming a powder bed containing the copper alloy powder for metal AM; and solidifying the copper alloy powder for metal AM at a predetermined position in the powder bed to form a building bed. According to the method for producing a copper alloy additive manufacturing object of Aspect 5 of the present invention, a copper alloy additive manufacturing object with excellent quality and few structural defects such as voids can be obtained.

[0020] Aspect 6 of the present invention is the method for producing a copper alloy additive manufacturing product according to Aspect 5, characterized in that it comprises an aging heat treatment step in which the copper alloy additive manufacturing product is maintained at a temperature in the range of 350° C. to 800° C. Aspect 7 of the present invention is the method for producing a copper alloy additive manufacturing product according to Aspect 5 or Aspect 6, characterized in that it comprises a solution heat treatment step in which the copper alloy additive manufacturing product is maintained at a temperature in the range of 900° C. to 950° C. According to the method for producing a copper alloy additive manufacturing product according to Aspect 6 or Aspect 7 of the present invention, a copper alloy additive manufacturing product having excellent mechanical properties can be obtained.

[0021] According to the present invention, it is possible to provide a copper alloy additive manufacturing body made of a Cu-Cr-Ni-Si alloy, which has few structural defects such as voids and has a high degree of crystal orientation.

[0022] 1 is a flow diagram of a method for manufacturing a copper alloy additive manufacturing object according to the present embodiment; 2 is a schematic explanatory diagram of copper alloy particles constituting a copper alloy powder for metal AM used in the present embodiment; 3 is a graph showing the relationship between laser energy density and crystal orientation of a copper alloy additive manufacturing object according to the present embodiment;

[0023] Hereinafter, a copper alloy additive manufacturing product according to one embodiment of the present invention will be described with reference to the accompanying drawings. The copper alloy additive manufacturing product according to this embodiment is manufactured by additive manufacturing using a copper alloy powder for metal AM made of a Cu-Cr-Ni-Si alloy.

[0024] The copper alloy additive manufacturing object of this embodiment is made of a Cu-Cr-Ni-Si alloy containing Cr in the range of 0.1% by mass to 0.8% by mass, Si in the range of 0.4% by mass to 0.8% by mass, and Ni in the range of 1.8% by mass to 3.0% by mass. The copper alloy additive manufacturing object of this embodiment preferably has a composition consisting of copper and impurities other than Cr, Si, and Ni. In other words, the copper alloy additive manufacturing object of this embodiment is made of a copper alloy corresponding to CDA No. C18000.

[0025] In the copper alloy additive manufacturing product of this embodiment, the lower limit of the Cr content is more preferably 0.2 mass% or more, and more preferably 0.3 mass% or more. The upper limit of the Cr content is more preferably 0.8 mass% or less, and more preferably 0.7 mass% or less. In the copper alloy additive manufacturing product of this embodiment, the lower limit of the Si content is more preferably 0.45 mass% or more, and more preferably 0.5 mass% or more. The upper limit of the Si content is more preferably 0.7 mass% or less, and more preferably 0.6 mass% or less. In the copper alloy additive manufacturing product of this embodiment, the lower limit of the Ni content is more preferably 1.9 mass% or more, and more preferably 2.0 mass% or more. The upper limit of the Ni content is more preferably 2.9 mass% or less, and more preferably 2.8 mass% or less.

[0026] In the copper alloy additive manufacturing product of this embodiment, the alloying elements are Cr, Ni, and Si, and the impurities are components containing impurity elements, O, H, and S. The copper alloy constituting the copper alloy additive manufacturing product of this embodiment may also contain additive elements and impurity elements other than the alloying elements (Cr, Ni, and Si). In the copper alloy additive manufacturing product, additive elements and impurity elements other than the alloying elements (Cr, Ni, and Si) constituting C18000 include, for example, one or more selected from Mg, Ti, Zr, Al, Zn, Ca, Sn, Pb, Fe, Mn, Te, P, Sb, Fe, Bi, Ag, and S.

[0027] In the copper alloy additive manufacturing product, the total amount of additive elements other than alloy elements and impurity elements (impurities excluding O, H, and S) is preferably 0.04 mass% or less, more preferably 0.03 mass% or less, even more preferably 0.02 mass% or less, and even more preferably 0.01 mass% or less or 0.006 mass% or less. In addition, in the copper alloy additive manufacturing product, the upper limit of the content of additive elements other than alloy elements and impurity elements (impurities excluding O, H, and S) is preferably 30 mass ppm or less, more preferably 20 mass ppm or less, and even more preferably 15 mass ppm or less.

[0028] The copper alloy additive manufacturing product of this embodiment has a density of 99.5% or more. That is, the copper alloy additive manufacturing product of this embodiment has almost no structural defects such as voids. The density of the copper alloy additive manufacturing product of this embodiment is more preferably 99.7% or more, and even more preferably 99.8% or more. The density of the copper alloy additive manufacturing product of this embodiment may be 99.85% or more, or may be 99.9% or more. The upper limit of the density of the copper alloy additive manufacturing product may be 100%.

[0029] The shaped body density is the packing density in the evaluation cross section of the copper alloy additive manufacturing body, calculated from the area of ​​the evaluation cross section of the copper alloy additive manufacturing body and the area occupied by voids observed in the evaluation cross section of the copper alloy additive manufacturing body using the following formula (1): shaped body density (%) = {(area of ​​evaluation cross section of copper alloy additive manufacturing body - area occupied by voids observed in the evaluation cross section of the copper alloy additive manufacturing body) / (area of ​​evaluation cross section of copper alloy additive manufacturing body)} × 100 (1) The area of ​​the evaluation cross section of the copper alloy additive manufacturing body and the area occupied by voids observed in the evaluation cross section of the copper alloy additive manufacturing body can be detected by observing the evaluation cross section of the copper alloy additive manufacturing body using an optical microscope.

[0030] In the copper alloy additive manufacturing product of this embodiment, as a result of crystal orientation measurement by electron backscatter diffraction, the area ratio of crystals having a plane orientation of {101} ± 15° in a specific direction is 51% or more. In this embodiment, when a plane perpendicular to the powder stacking direction is used as the measurement surface, the area ratio of crystals having a plane orientation of {101} ± 15° in the stacking direction is 51% or more. Note that in the copper alloy additive manufacturing product of this embodiment, as a result of crystal orientation measurement by electron backscatter diffraction, the area ratio of crystals having a plane orientation of {101} ± 15° in at least one specific direction is more preferably 55% or more, and even more preferably 60% or more. In the copper alloy additive manufacturing product of this embodiment, as a result of crystal orientation measurement by electron backscatter diffraction, the area ratio of crystals having a plane orientation of {101} ± 15° in a specific direction may be 65% or more. Furthermore, as a result of measuring the crystal orientation by electron backscatter diffraction, the upper limit of the area ratio of crystals having a plane orientation of {101}±15° in at least one specific direction may be 99.9%.

[0031] Crystal orientation measurement by electron backscatter diffraction can be performed as follows. When the powder stacking direction of a copper alloy additive manufacturing object is known, for example, because it is connected to a base plate, a sample coordinate system is defined based on the base plate surface, and the direction perpendicular to the base plate surface (stacking direction) is defined as the A3 direction. Furthermore, based on this A3 direction, the A2 direction is defined as a direction parallel to the sample cross section of EBSD (Electron Backscattered Diffraction) analysis and perpendicular to the A3 direction, and the A1 direction is defined as a direction perpendicular to the sample cross section of EBSD analysis and perpendicular to the A3 direction. When analyzing the orientation density of a specific crystal plane, for example, when analyzing the orientation density in the A3 direction, the percentage of the crystal plane being analyzed that falls within an angle range of ±15° with respect to the A3 direction is used.

[0032] On the other hand, after the copper alloy additive manufacturing product is separated from the base plate as an independent part, the orientation can be analyzed by, for example, analyzing the crystal orientation of the copper alloy additive manufacturing product using the X-ray reflection Laue method. Then, after confirming the orientation with the maximum intensity of the {101} orientation, the orientation density of the {101} orientation within the range of {101}±15° can be confirmed by EBSD analysis. Therefore, the orientation density of the {101} orientation within the range of {101}±15°, i.e., the area fraction of crystals having a plane orientation of {101}±15°, within the measurement area of ​​the sample cross section can be obtained by EBSD analysis.

[0033] Here, according to the literature (Journal of the Society of Materials Science, Japan, Vol. 67, No. 9, pp. 855 (2018)), when the elastic constant and the crystal plane index {hkl} are taken into consideration, the elastic modulus of Cu crystal (FCC crystal) is expressed by the following formula (2).

[0034] The above formula and the elastic modulus C of Cu crystal described in the literature (Charles Kittel, Introduction to Solid State Physics - 7th ed., 1996, John Wiley & Sons, Inc. (ISBN 0-471-11181-3)) １１ , C １２ , C ４４ By using this, for example, the Young's modulus E(100) of the (100) plane of a Cu crystal and the Young's modulus E(101) of the (101) plane of the Cu crystal are calculated as follows: E(101) = 131 GPa E(100) = 68 GPa Therefore, in the copper alloy additive manufacturing product of this embodiment, the area ratio of crystals having a plane orientation of {101} ± 15° is 51% or more, and since the crystal planes are highly oriented in one direction (stacking direction), the mechanical properties in this direction are different from those in other directions and the product has anisotropy.

[0035] Furthermore, in the copper alloy additive manufacturing product of this embodiment, if the oxygen concentration is high, structural defects such as voids are more likely to occur in the laminate structure. Therefore, in the copper alloy additive manufacturing product of this embodiment, the oxygen concentration is preferably 80 mass ppm or less. The oxygen concentration is more preferably 70 mass ppm or less, and even more preferably 30 mass ppm or less. The lower limit of the oxygen concentration is not particularly limited, but may be 10 mass ppm. Furthermore, in the copper alloy additive manufacturing product of this embodiment, the hydrogen concentration is preferably 1 mass ppm or less, and the sulfur concentration is preferably 8 mass ppm or less. Furthermore, in the copper alloy additive manufacturing product of this embodiment, the sulfur concentration is more preferably 6 mass ppm or less, and even more preferably 5 mass ppm or less. Furthermore, in the copper alloy additive manufacturing product of this embodiment, the sulfur concentration may be 4 mass ppm or less or 3 mass ppm or less. The lower limit of the sulfur concentration is not particularly limited, but may be 0.5 mass ppm.

[0036] In a copper alloy additive manufacturing product, the oxygen concentration can be measured by inert gas fusion-infrared absorption, the hydrogen concentration by inert gas fusion-thermal conductivity, and the sulfur concentration by combustion-infrared absorption. The Ni concentration, Si concentration, Cr concentration, and the concentrations of additive elements other than alloy elements and impurity elements (impurities excluding O, H, and S) in the copper alloy additive manufacturing product can be obtained by an appropriate combination of X-ray fluorescence analysis, glow discharge mass spectrometry, and inductively coupled plasma mass spectrometry.

[0037] Furthermore, as described above, the copper alloy additive manufacturing product of this embodiment is composed of a Cu-Cr-Ni-Si alloy, which is a precipitation-strengthened copper alloy, and therefore may be used as a conductive member. Therefore, the copper alloy additive manufacturing product of this embodiment preferably has a conductivity of 20% IACS or higher. The conductivity is more preferably 38% IACS or higher, and even more preferably 40% IACS or higher. The upper limit of the conductivity is not particularly limited, but may be 50% IACS. The conductivity of the copper alloy additive manufacturing product can be obtained by measuring using a vortex conductivity meter.

[0038] Next, a method for manufacturing a copper alloy additive manufacturing object according to this embodiment will be described with reference to the flow diagram of Fig. 1. The method for manufacturing a copper alloy additive manufacturing object shown in Fig. 1 includes a powder preparation step S01 for preparing a copper alloy powder for metal AM, a manufacturing step S02 for manufacturing a copper alloy additive manufacturing object by additive manufacturing the copper alloy powder for metal AM, and a heat treatment step S03.

[0039] (Powder preparation step S01) In this powder preparation step S01, a copper alloy powder for metal AM made of a Cu-Cr-Ni-Si alloy is prepared. In the copper alloy powder for metal AM used in this embodiment, either one or both of a CrSi-based compound containing Cr and Si and a NiSi-based compound containing Ni and Si are precipitated at the copper crystal grain boundaries on the particle surfaces.

[0040] In the copper alloy powder for metal AM according to this embodiment, it is preferable that either one or both of a CrSi-based compound containing Cr and Si and a NiSi-based compound containing Ni and Si are precipitated on the copper crystal grains on the particle surfaces constituting the copper alloy powder. Here, in this embodiment, the particle surface of the copper alloy powder for metal AM refers to the region from the outermost surface of the particle to a depth of 100 nm.

[0041] 2, the copper alloy particles 50 of the copper alloy powder for metal AM used in this embodiment have a CrSiNi-containing layer 52 containing either a CrSi-based compound or a NiSi-based compound, or both, formed on the particle surface. That is, the copper alloy particles 50 of the copper alloy powder for metal AM used in this embodiment preferably have a particle body 51 made of a copper alloy containing Cr, Ni, and Si, and a CrSiNi-containing layer 52 on the outer surface of the particle body 51, which contains either a CrSi-based compound containing Cr and Si, or a NiSi-based compound containing Ni and Si, or both. The thickness of the CrSiNi-containing layer 52 on the particle surface of the copper alloy powder for metal AM is preferably 1 nm or more and 100 nm or less.

[0042] The particle body 51 of the copper alloy particle 50 of the copper alloy powder for metal AM used in this embodiment is polycrystalline, and it has been confirmed that either or both of a CrSi-based compound containing Cr and Si and a NiSi-based compound containing Ni and Si are distributed on the surface of the particle body 51. Note that either or both of the CrSi-based compound containing Cr and Si and the NiSi-based compound containing Ni and Si are distributed both at the copper crystal grain boundaries and on the copper crystal grains.

[0043] In the copper alloy powder for metal AM used in this embodiment, it is preferable that the volume-based 50% cumulative particle diameter D50 measured by a laser diffraction / scattering method is in the range of 10 μm or more and 120 μm or less, the 10% cumulative particle diameter D10 is in the range of 1 μm or more and 80 μm or less, and the 90% cumulative particle diameter D90 is in the range of 10 μm or more and 150 μm or less.

[0044] The copper alloy powder for metal AM used in this embodiment is produced by producing a high-purity copper alloy ingot with few impurities using a continuous melting and casting apparatus, processing this copper alloy ingot into a wire rod and cutting it to form a copper alloy raw material, and atomizing this copper alloy raw material. Here, in the copper alloy ingot produced by the continuous melting and casting apparatus, the O concentration is preferably 10 mass ppm or less, the H concentration is 5 mass ppm or less, the S concentration is 15 mass ppm or less, and the total content of impurity elements other than Cu (impurities excluding O, H, and S) is preferably 0.04 mass% or less. Furthermore, in the above-mentioned copper alloy raw material, the O concentration is preferably 10 mass ppm or less, the H concentration is 5 mass ppm or less, the S concentration is 15 mass ppm or less, and the total content of impurity elements other than Cu and alloy elements (impurities excluding O, H, and S) is preferably 0.04 mass% or less.

[0045] In the copper alloy powder for metal AM used in this embodiment, it is preferable that the O concentration is 1000 mass ppm or less, the H concentration is 5 mass ppm or less, the S concentration is 10 mass ppm or less, and the N concentration is 10 mass ppm or less. In the copper alloy powder for metal AM, the total amount of additive elements other than alloy elements and impurity elements (impurities excluding O, H, and S) may be 0.07 mass% or less, 0.06 mass% or less, or 0.05 mass% or less, preferably 0.04 mass% or less, more preferably 0.03 mass% or less, even more preferably 0.02 mass% or less, and even more preferably 0.01 mass% or less. In addition, in the copper alloy powder for metal AM, the upper limit of the content of each of additive elements other than alloy elements and impurity elements (impurities excluding O, H, and S) is preferably 30 mass ppm or less, more preferably 20 mass ppm or less, and even more preferably 15 mass ppm or less.

[0046] In the copper alloy powder for metal AM of this embodiment, the alloying elements are Cr, Ni, and Si, and the impurities are components containing impurity elements, O, H, and S. Furthermore, the copper alloy constituting the copper alloy powder for metal AM of this embodiment may contain additive elements and impurity elements other than the alloying elements (Cr, Ni, and Si). In the copper alloy powder for metal AM, additive elements and impurity elements other than the alloying elements (Cr, Ni, and Si) constituting C18000 can include, for example, one or more selected from Mg, Ti, Ni, Si, Al, Zn, Ca, Sn, Pb, Fe, Mn, Te, P, Sb, Fe, Bi, Ag, and S.

[0047] In this embodiment, as described above, the atomization process is performed using a molten alloy with a sufficiently reduced impurity content, which prevents Cr and Si from reacting with the impurities and consuming them, and makes it possible to precipitate CrSi-based compounds containing Cr and Si and NiSi-based compounds containing Ni and Si at least at the copper crystal grain boundaries on the particle surfaces of the copper alloy powder for metal AM. During this atomization process, sufficient vacuum drawing and atmospheric control using high-purity gases make it possible to produce a higher quality copper alloy powder for metal AM.

[0048] (Shaping process S02) In this shaping process S02, a copper alloy laminate shaped body is produced by sequentially repeating a powder bed formation process S21 in which a powder bed containing the above-mentioned copper alloy powder for metal AM is formed, and a shaping bed formation process S22 in which the copper alloy powder for metal AM is solidified at a predetermined position in the powder bed to form a shaping bed.

[0049] In the building bed formation step S22, a laser is used to solidify the copper alloy powder for metal AM. As shown in Figure 3, by setting the laser energy density high, the degree of orientation of crystals with a plane orientation of {101} ± 15° in the stacking direction increases. Therefore, in this embodiment, the laser energy density in the building bed formation step S22 is set to 100 J / mm ３ It is preferable to set the value to 150 J / mm or more. ３ More preferably, it is set to the above.

[0050] (Heat Treatment Step S03) Next, if necessary, heat treatment is performed to appropriately precipitate precipitates, thereby improving electrical conductivity and strength. Here, the heat treatment may include solution heat treatment and aging heat treatment. The solution heat treatment is preferably performed under the following conditions: a heat treatment temperature of 900°C to 950°C, and a holding time at the heat treatment temperature of 0.1 to 1 hour. The aging heat treatment is preferably performed under the following conditions: a heat treatment temperature of 350°C to 800°C, more preferably 350°C to 600°C, and a holding time at the heat treatment temperature of 1 to 3 hours. If the solution treatment has progressed sufficiently in the shaping step S02, the solution heat treatment may be omitted and only the aging heat treatment may be performed directly. This direct aging heat treatment can also achieve the mechanical properties required for practical use by heat treatment in the temperature range shown in the examples described below. If the solution treatment has progressed sufficiently in the shaping step S02, the heat treatment step S03 may be omitted.

[0051] The copper alloy additive manufacturing object of this embodiment is manufactured by the various steps described above.

[0052] The copper alloy additive manufacturing body of this embodiment, configured as described above, is composed of a Cu-Cr-Ni-Si alloy having a Cr content in the range of 0.1 mass% or more and 0.8 mass% or less, a Si content in the range of 0.4 mass% or more and 0.8 mass% or less, and a Ni content in the range of 1.8 mass% or more and 3.0 mass% or less. Therefore, it has excellent conductivity and strength and can be widely used as a material for various parts.

[0053] Furthermore, in the copper alloy additive manufacturing product of this embodiment, the density of the manufactured product is 99.5% or more, so there are few structural defects such as voids, and the quality is excellent. Furthermore, in the copper alloy additive manufacturing product of this embodiment, as a result of crystal orientation measurement by electron backscatter diffraction (EBSD), the area ratio of crystals having a plane orientation of {101}±15° in a specific direction (in this embodiment, the stacking direction) is 51% or more, which means that the crystal orientation is highly oriented and the mechanical properties are sufficiently anisotropic. Therefore, the copper alloy additive manufacturing product of this embodiment is particularly suitable as a copper alloy part for applications requiring anisotropy in mechanical properties.

[0054] Furthermore, in the copper alloy additive manufacturing product of this embodiment, when the oxygen concentration is 80 ppm by mass or less, the number of oxygen-induced defects is further reduced, resulting in excellent quality. Furthermore, in the copper alloy additive manufacturing product of this embodiment, when the electrical conductivity is 20% IACS or more, this copper alloy additive manufacturing product can be suitably used as a conductive member. Furthermore, in the copper alloy additive manufacturing product of this embodiment, when the sulfur concentration is 8 ppm by mass or less, the number of structural defects such as sulfur-induced voids is further reduced, the electrical conductivity is excellent, and the quality is excellent.

[0055] The above describes a copper alloy additive manufacturing body and a method for manufacturing a copper alloy additive manufacturing body that are embodiments of the present invention, but the present invention is not limited to this and can be modified as appropriate within the scope of the technical concept of the invention.

[0056] The results of confirmation experiments conducted to confirm the effects of the present invention will be described below.

[0057] (Test 1) First, a copper raw material made of 4N-grade high-purity copper was prepared, and a C18000 copper alloy ingot was produced using a continuous melting and casting apparatus. The O concentration of the copper alloy ingot was 10 mass ppm or less, the H concentration was 5 mass ppm or less, the S concentration was 15 mass ppm or less, and the total content of impurity elements other than Cu (impurities excluding O, H, and S) was 0.04 mass% or less. Next, using the produced C18000 composition copper alloy ingot as a raw material, a copper alloy powder for metal AM of Example 1 of the present invention was produced by a gas atomization method using argon gas, and the powder was classified to a particle size suitable for the powder bed of laser PBF. For the copper alloy powder for metal AM of Example 1 of the present invention, the particle size distribution was measured by a wet method using an MT3300EXII manufactured by Microtrac, and the 10% cumulative particle diameter D10, 50% cumulative particle diameter D50, and 90% cumulative particle diameter D90 on a volume basis were calculated from the obtained results. For the copper alloy powder for metal AM after classification of the present invention, the particle size distribution was measured by this method, and the volume-based D10 was 20 μm, D50 was 31 μm, and D90 was 47 μm. The component composition of the obtained copper alloy powder for metal AM is shown in Table 1.

[0058] Using the copper alloy powder for metal AM of Example 1 of the present invention, layered models A and B of Example 1 of the present invention were produced using a commercially available laser PBF printer. The light source was a 400 W Yb fiber laser, and the laser spot diameter was approximately 100 μm. The laser energy density during modeling was 84 J / mm ３ to 440 J / mm ３ The compositions of the obtained copper alloy additive manufacturing bodies A and B of Example 1 of the present invention are shown in Table 1.

[0059] The O concentration in the copper alloy powder for metal AM and the copper alloy additive manufacturing body shown in Table 1 was determined by inert gas fusion-infrared absorption spectrometry, the H concentration by inert gas fusion-thermal conductivity spectrometry, and the S concentration by combustion-infrared absorption spectrometry. The concentrations of components other than these substances, excluding copper, were determined by an appropriate combination of X-ray fluorescence spectrometry, glow discharge mass spectrometry, and inductively coupled plasma mass spectrometry.

[0060]

[0061] As shown in Table 1, the copper alloy powder for metal AM of Example 1 and the copper alloy additive manufacturing bodies A and B of Example 1 all had a C18000 composition, and the contents of alloy elements (Ni, Si, Cr) did not change significantly. On the other hand, it was confirmed that the oxygen concentration of the copper alloy additive manufacturing bodies was reduced compared to the oxygen concentration of the copper alloy powder for metal AM. It is presumed that oxygen was removed during the process of melting the copper alloy powder for metal AM by laser PBF.

[0062] Next, as Comparative Example 1, a copper alloy additive manufacturing body D was produced using a commercially available laser PBF printer using a commercially available copper alloy powder for metal AM with the C18000 composition shown in Table 1. The light source was a 400 W Yb fiber laser, and the laser spot diameter was approximately 100 μm. The commercially available copper alloy powder for metal AM with the C18000 composition had a high S concentration and a high content of impurity elements other than Cu (excluding O, H, and S).

[0063] Next, the copper alloy additive manufacturing body A of Example 1 of the present invention and the copper alloy additive manufacturing body D of Comparative Example 1 were evaluated for the density and the orientation of the crystal orientation as follows.

[0064] (Model Density) The packing density of the evaluation cross section of the copper alloy additive manufacturing body A and the copper alloy additive manufacturing body D was evaluated from the area of ​​the evaluation cross section and the area occupied by voids observed in the evaluation cross section. Specifically, the cross section of the copper alloy additive manufacturing body was subjected to machining including mirror polishing, and then the evaluation cross section of the copper alloy additive manufacturing body was observed using an optical microscope to confirm void locations within the evaluation cross section of the measurement target. The area occupied by voids in the evaluation cross section was calculated, and the model density was determined using formula (1). The evaluation results of the model density are shown in Table 2. Model Density (%) = {(Area of ​​evaluation cross section of copper alloy additive manufacturing body - Area occupied by voids observed in the evaluation cross section of the copper alloy additive manufacturing body) / (Area of ​​evaluation cross section of copper alloy additive manufacturing body)} × 100 (1) The copper alloy additive manufacturing body A of Example 1 of the present invention and the copper alloy additive manufacturing body D of Comparative Example 1 shown in Table 2 had a packing density of 330 J / mm ３ It was shaped under certain conditions.

[0065] (Crystal orientation orientation) The crystal orientation characteristics of the copper alloy laminate shaped body A and the copper alloy laminate shaped body D were evaluated using scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD) (hereinafter abbreviated as EBSD). In the evaluation by the EBSD method, FEI Quanta FEG 450, EDAX TSL OIM Data Collection, and analysis software (EDAX TSL OIM Data Analysis ver. 5.3) were used. The acceleration voltage of the electron beam for EBSD analysis was 20 kV, the measurement interval was 0.1 μm steps, and the measurement area was 800 μm × 1200 μm. The crystal orientation of each crystal grain in the cross section of the shaped body was analyzed.

[0066] When the base plate of the copper alloy additive manufacturing sample is the bottom surface of the sample, additive manufacturing is performed in a vertical direction upward from the base plate surface, and this direction is defined as the building direction (BD). Here, the A3 direction corresponds to the BD direction, and the A1, A2, and A3 directions are perpendicular to each other.

[0067] Next, assuming that the allowable range of deviation angles of the designated crystal plane directions of the copper crystal from the coordinate axis direction of each sample was 0 to 15 degrees, the area occupancy (crystal area ratio) of crystal grains having the orientation characteristics of the designated crystal planes within this allowable angle range was calculated on the measured cross section of the sample. Here, the area occupancy of crystal grains was calculated by integrating the areas of crystal grains having the orientation characteristics of each designated crystal plane within a measurement area of ​​800 μm × 1200 μm on the cross section of each sample. Since this area occupancy indicates the orientation characteristics of each designated crystal plane, in the present invention, this area occupancy was used to calculate the orientation degree of a certain designated crystal plane direction.

[0068]

[0069] As shown in Table 2, the copper alloy additive manufacturing body A of Inventive Example 1 had a density of 99.8%. The density of the copper alloy additive manufacturing body A of Inventive Example 1 was higher than that of the copper alloy additive manufacturing body D of Comparative Example 1, and was close to 100%, confirming that it was almost free of structural defects such as voids and had excellent quality. Furthermore, it was confirmed that the copper alloy additive manufacturing body A of Inventive Example 1 exhibited a higher degree of orientation in all crystal plane directions, namely the A1 direction, the A2 direction, and the A3 direction, compared to the copper alloy additive manufacturing body D of Comparative Example 1.

[0070] In particular, it was confirmed that the copper alloy additive manufacturing object A of Example 1 exhibited a very high degree of orientation in the A3 direction, with the area ratio of crystals having a plane orientation of {101}±15° being 69.0%. On the other hand, in the copper alloy additive manufacturing object of the comparative example, the area ratio of crystals having a plane orientation of {101}±15° in the A3 direction was 50.3%. From these comparisons, it was confirmed that the copper alloy additive manufacturing object of the present invention had a clearly high degree of orientation.

[0071] (Test 2) As in Inventive Example 1, a copper raw material made of 4N-grade high-purity copper was prepared, and a continuous melting and casting apparatus was used to produce a C18000 copper alloy ingot having an O concentration of 10 mass ppm or less, an H concentration of 5 mass ppm or less, an S concentration of 15 mass ppm or less, and a total content of impurity elements other than Cu (impurities excluding O, H, and S) of 0.04 mass% or less. Next, as in Inventive Example 1, a copper alloy powder for metal AM was produced using the produced copper alloy ingot with C18000 composition as a raw material, and the powder was classified to a particle size suitable for the powder bed of laser PBF. Next, using the same method as in Inventive Example 1, a copper alloy powder for metal AM was produced using a C18000 composition ingot .... ３ to 214 J / mm ３ The copper alloy additive manufacturing object of Inventive Example 2 was produced at an energy density of 100 MPa. The obtained copper alloy additive manufacturing object of Inventive Example 2 was confirmed to have the same component composition, manufacturing density, and area ratio of crystals with a plane orientation of {101}±15° in the A3 direction as the copper alloy additive manufacturing object A of Inventive Example 1.

[0072] Next, the copper alloy additive manufacturing product of Inventive Example 2 was subjected to heat treatment under heat treatment conditions 1-1 to 1-8 shown in Table 3, and the Vickers hardness (HV units) was measured at room temperature. The measurement results are shown in Table 3. The Vickers hardness was measured in accordance with JIS Z 2244. The copper alloy additive manufacturing product of Inventive Example 2 was also subjected to heat treatment under heat treatment conditions 2-1 to 2-7 shown in Table 4, and the electrical conductivity was measured. The measurement results are shown in Table 4. The electrical conductivity was measured at room temperature using an eddy current conductivity meter.

[0073] Furthermore, the copper alloy additive manufacturing body of Inventive Example 2 was subjected to direct aging heat treatment without solution heat treatment under heat treatment conditions 3-1 to 3-4 shown in Table 5. The Vickers hardness (HV units) of the copper alloy additive manufacturing body after this aging heat treatment was measured at room temperature. The measurement results are shown in Table 5. The Vickers hardness was measured in accordance with JIS Z 2244. The density of the manufactured body was also calculated using formula (1) in the same manner as in Test 1. The evaluation results of the manufactured body density are shown in Table 5.

[0074] Furthermore, 147 J / mm ３ The copper alloy additive manufacturing body of Example 2 of the present invention, fabricated at an energy density of 1000 kJ / cm², was subjected to a solution heat treatment (950°C x 15 minutes) and an aging heat treatment (420°C x 2.2 hours). Tensile test specimens were prepared with the longitudinal direction perpendicular to the lamination direction, and the tensile strength was measured in the longitudinal direction of the test specimen. The copper alloy additive manufacturing body after this heat treatment was subjected to a tensile test at room temperature according to the ASTM E8 / E8M-22 standard, and the 0.2% proof stress, tensile strength, elongation, and reduction of area of ​​the heat-treated body were measured. The electrical conductivity at room temperature was also measured using a vortex conductivity meter. The measurement results are shown in Table 6.

[0075]

[0076]

[0077]

[0078]

[0079] As shown in Table 3, it was confirmed that the Vickers hardness can be adjusted by adjusting the aging heat treatment conditions. Furthermore, as shown in Table 4, it was confirmed that the electrical conductivity increases by performing solution heat treatment and aging heat treatment. As shown in Table 5, it was confirmed that the mechanical properties such as Vickers hardness can be improved in the copper alloy additive manufacturing body of Inventive Example 2 by performing aging heat treatment directly without solution heat treatment after additive manufacturing. In particular, it was confirmed that when the aging heat treatment temperature is 500°C, the Vickers hardness can be increased to 180 HV without performing high-temperature solution heat treatment. Furthermore, as shown in Table 6, it was confirmed that a copper alloy laminate with excellent mechanical properties and electrical conductivity can be obtained by performing heat treatment under appropriate conditions.

[0080] From the above, it has been confirmed that the present invention can provide a copper alloy additive manufacturing body made of a Cu-Cr-Ni-Si alloy, which has few structural defects such as voids and has a high degree of crystal orientation.

Claims

1. A copper alloy additive manufacturing object made of a Cu-Cr-Ni-Si alloy, wherein the Cu-Cr-Ni-Si alloy has a Cr content in the range of 0.1% by mass or more and 0.8% by mass or less, a Si content in the range of 0.4% by mass or more and 0.8% by mass or less, and a Ni content in the range of 1.8% by mass or more and 3.0% by mass or less, the copper alloy additive manufacturing object has a density of 99.5% or more, and as a result of crystal orientation measurement by electron backscatter diffraction, the area ratio of crystals having a plane orientation of {101}±15° in a specific direction is 51% or more.

2. The copper alloy additive manufacturing body according to claim 1, characterized in that the oxygen concentration is 80 mass ppm or less.

3. The copper alloy additive manufacturing product according to claim 1, characterized in that the electrical conductivity is 20% IACS or more.

4. The copper alloy additive manufacturing product according to claim 1, characterized in that the sulfur concentration is 8 mass ppm or less.

5. A method for manufacturing a copper alloy layered shaped body according to claim 1, comprising: a step of preparing copper alloy powder for metal AM; a powder bed formation step of forming a powder bed containing said copper alloy powder for metal AM; and a shaping bed formation step of solidifying said copper alloy powder for metal AM at a predetermined position in said powder bed to form a shaping bed.

6. The method for producing a copper alloy additive manufacturing body according to claim 5, further comprising an aging heat treatment step in which the copper alloy additive manufacturing body is maintained at a temperature in the range of 350°C or higher and 800°C or lower.

7. A method for producing a copper alloy laminated shaped body according to claim 5 or claim 6, comprising a solution heat treatment process in which the copper alloy laminated shaped body is maintained at a temperature in the range of 900°C or higher and 950°C or lower.

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