Cu-based alloy molded body

Abstract

To provide a molded body that is made by lamination molding using Cu-based alloy powder and comprises a Cu-based alloy having high density and excellent heat conductivity.SOLUTION: Provided is a molded body that is lamination molded using a Cu-based alloy powder containing, in mass%, Cr: 0.10 to 1.00% and any one or two or more of Nd, Gd, Dy and Y by 0.10 to 5.00% in total, and the balance being Cu and inevitable impurities, and that is made of a Cu-based alloy having a precipitate size of 20 μm or less.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a shaped body made of a Cu-based alloy, and more particularly to a shaped body made of a Cu-based alloy produced by an additive manufacturing method using a Cu-based alloy powder. [Background technology]

[0002] 3D printers are beginning to be used to create metal objects. These 3D printers create objects using additive manufacturing, and typical methods of metal additive manufacturing include the powder bed method (powder bed fusion method) and the metal deposition method (directed energy deposition method). In the powder bed method, the irradiated areas of the spread powder melt and solidify when irradiated with a laser beam or electron beam. This melting and solidification bonds the powder particles together. Irradiation is selectively performed on parts of the metal powder, and the non-irradiated areas do not melt, and a bond layer is formed only in the irradiated areas.

[0003] New metal powder is spread on the formed bond layer, and the metal powder is irradiated with a laser beam or an electron beam. The irradiation melts and solidifies the metal particles, forming a new bond layer. The new bond layer also bonds with the existing bond layer.

[0004] By repeatedly melting and solidifying the material by irradiation with a laser beam or the like, the assembly of bonding layers gradually grows. This growth results in a three-dimensional object. By using this type of additive manufacturing method, objects with complex shapes can be easily obtained.

[0005] As a powder bed type additive manufacturing method, a mixture of "iron-based powder" and "one or more types of powder selected from the group consisting of nickel, nickel-based alloy, copper, copper-based alloy, and graphite" is used as the metal powder for metal laser sintering, and a procedure is disclosed in which the metal powder is spread in a powder layer formation step, a sintered layer formation step in which a beam is irradiated onto the powder layer to form a sintered layer, and a removal step in which the surface of the shaped body is cut are repeated to form a sintered layer, thereby producing a three-dimensional shaped body (see Patent Document 1).

[0006] In conventional additive manufacturing methods using metal powders, maraging steel, stainless steel, Ti (titanium), etc. are used. In recent years, there has been a demand for Cu (copper), Al (aluminum), etc. as materials for additive manufacturing. In particular, Cu and Cu-based alloys are suitable for applications requiring high electrical conductivity in the resulting molded body.

[0007] In the additive manufacturing method, a fiber laser or a YAG laser in the near-infrared wavelength region (near 1000 nm wavelength) is usually used to rapidly melt the metal material, and then rapidly cool and solidify it. However, Cu and Cu-based alloys have high thermal conductivity and large energy diffusion. For example, when irradiated with a YAG laser with a wavelength of 1064 nm, the laser light absorption rate of pure Cu is low at about 10%. Due to this low laser light absorption rate, there is a problem that it is difficult to melt Cu and Cu-based alloys by laser irradiation, or even if it can be melted, the energy efficiency is extremely low.

[0008] In addition, the laser reflectivity of pure Cu is high compared to that of Fe-based alloys, Ni-based alloys, Co-based alloys, etc. When pure Cu powder is used in a process involving rapid melting and rapid solidification, such as additive manufacturing, a lot of heat is released into the atmosphere due to the high laser reflectivity. Therefore, the powder is not given enough heat to melt. The lack of heat leads to poor bonding between particles. Due to the lack of heat, unmelted particles remain inside the molded body obtained from this powder. As a result, the relative density of this molded body is low.

[0009] It is true that if a laser with a high energy density is irradiated onto pure Cu powder, the remaining unmelted particles are suppressed. However, irradiation with a laser with a high energy density leads to bumping of the molten metal. This bumping is one of the causes of voids inside the molded object. Since the relative density of a molded object with voids will be low, it is not enough to simply irradiate it with a laser with a high energy density.

[0010] Patent document 2 proposes a technology for improving the absorption rate of the shaping light beam by irradiating a metal powder with an assist light beam of a different wavelength from the shaping light beam and forming an oxide film on the surface of the metal powder (see Patent Document 2).

[0011] In addition, as a raw material for additive manufacturing, a copper powder has been proposed which has a copper powder body made of copper or a copper alloy and an oxide coating formed on the surface of the copper powder body by heat treatment in the presence of oxygen (see Patent Document 3). [Prior art documents] [Patent documents]

[0012] [Patent Document 1] JP 2008-81840 A [Patent Document 2] JP 2017-141505 A [Patent Document 3] JP 2019-123920 A Summary of the Invention [Problem to be solved by the invention]

[0013] The powders for additive manufacturing disclosed in Patent Documents 2 and 3 have an oxide film formed on the surface, and therefore their production requires a specific oxidation treatment, which makes their production time-consuming. In addition, in Cu-based alloys, when the additive elements are dissolved in the copper matrix, they impede thermal conduction, so by subjecting the molded body to aging heat treatment after additive manufacturing, the additive elements are expelled from the copper matrix as precipitates, and the thermal conductivity of copper can be restored. However, if the expelled precipitates (the additive elements alone, or intermetallic compounds of copper and the additive elements) are too large, they will block the paths for thermal conduction. Therefore, the object of the present invention is to obtain a shaped body made of a Cu-based alloy having a high relative density, high thermal conductivity, and a precipitate size of 20 μm or less, which is produced by an additive manufacturing method using a Cu-based alloy powder that is obtained without the need for any special oxidation treatment and that has a high laser light absorption rate and can produce high-density shaped bodies. [Means for solving the problem]

[0014] As a result of extensive research, the inventors have discovered that in a Cu-based alloy to which Cr (chromium) and a specific element having a lower standard energy of oxide formation than Cr has been added, laser irradiation during additive manufacturing promotes the generation of oxides and significantly improves the laser light absorption rate. Using this Cu-based alloy powder, the inventors have been able to obtain a shaped body made of a Cu-based alloy having high relative density and excellent thermal conductivity.

[0015] First, the Cu-based alloy powder used for the shaped body according to the present invention is a Cu-based alloy containing "Cr" and "one or more elements selected from the group consisting of Nd, Gd, Dy, and Y." In this Cu-based alloy, the total content of Nd (neodymium), Gd (gadolinium), Dy (dysprosium) and Y (yttrium) is, in mass%, 0.10% or more and 5.00% or less. Therefore, the first means for solving the problems of the present invention is a shaped body made of a Cu-based alloy having a precipitate size of 20 μm or less, using a Cu-based alloy powder containing, in mass%, 0.10 to 1.00% Cr, and 0.10 to 5.00% in total of one or more of Nd, Gd, Dy, and Y, with the remainder being Cu and unavoidable impurities.

[0016] The second means is a shaped body made of a Cu-based alloy having a precipitate size of 20 μm or less, which is produced by additive manufacturing using the Cu-based alloy powder described in the first means, in which the Si, P, and S contents of the unavoidable impurities are Si: 0.20% or less, P: 0.100% or less, and S: 0.100% or less. In other words, the Cu-based alloy powder described in the second means is the Cu-based alloy powder described in the first means, characterized in that, among the unavoidable impurities of the Cu-based alloy powder, the Si content is 0.20% or less, the P content is 0.10% or less, and the S content is 0.10% or less. Therefore, the second means of the present invention is a shaped body made of a Cu-based alloy having a precipitate size of 20 μm or less, which is produced by additive manufacturing using the Cu-based alloy powder.

[0017] The Si in the Cu-based alloy powder according to the present invention is not intentionally added, but is an inevitable impurity. Therefore, the Si content in the Cu-based alloy powder according to the present invention may be 0%, with the upper limit being 0.20%. In addition, since P and S in the Cu-based alloy powder are also inevitable impurities, they may both be 0%, with the upper limits of P and S being 0.10% each.

[0018] In addition, preferably, the Cu-based alloy powder has an average particle diameter D 50 (μm) and tap density TD (Mg / m 3 ) and D 50 / TD value is 0.2×10 -5 m 4 / Mg or more 20×10 -5 m 4 / Mg or less.

[0019] Therefore, the third method is to measure the average particle diameter D 50 (μm) and tap density TD (Mg / m 3 ) and D 50 / TD value is 0.2×10 -5 ~20×10 -5 m 4 The present invention relates to a shaped body made of a Cu-based alloy having a precipitate size of 20 μm or less, which is produced by additive manufacturing using the Cu-based alloy powder according to the first or second means, wherein the Cu-based alloy powder has a composition ratio of 1:1 / Mg and a sphericity of 0.80 to 0.95.

[0020] Moreover, the content of oxygen (O) in the Cu-based alloy powder is preferably 0.1% (1000 ppm) or less.

[0021] Preferably, the sphericity of the Cu-based alloy powder is 0.80 to 0.95.

[0022] Preferably, the Cu-based alloy powder has a laser light absorptance of 30% or more at a wavelength of 1064 nm. Effect of the Invention

[0023] The Cu-based alloy powder according to the present invention has a high laser light absorption rate, so by applying this Cu-based powder to an additive manufacturing method, a high-density shaped body can be obtained. This is because there is no need to excessively increase the energy density during irradiation, so that a shaped body can be obtained while avoiding bumping and the like. Furthermore, by making the precipitate size in the shaped body 20 μm or less, the heat conduction path is not easily blocked by the precipitate even after aging treatment, so that a shaped body with excellent thermal conductivity can be obtained. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Prior to describing the embodiments of the present invention, the reasons for specifying the component composition of the Cu-based alloy powder used for additive manufacturing of the shaped body of the present invention will be described. In the present specification, unless otherwise specified, the "average particle size" refers to the particle size D at the point where the cumulative volume is 50% in a volume-based cumulative curve obtained by a laser diffraction scattering method. 50 (Median diameter). "X to Y" indicating a range means "X or more and Y or less". Furthermore, % in the composition of the Cu-based alloy powder means mass %, and ppm means mass ppm.

[0025] The Cu-based alloy powder (hereinafter, may be referred to as "alloy powder") used in the additive manufacturing of the shaped body of the present invention is an aggregate of many particles. The material of each particle is a Cu-based alloy.

[0026] [Cu-based alloy] The Cu-based alloy powder used in the additive manufacturing of the shaped body of the present invention contains Cr and one or more elements selected from the group consisting of Nd, Gd, Dy, and Y, with the balance being Cu and unavoidable impurities. The total content of Nd, Gd, Dy, and Y in this Cu-based alloy is 0.10 to 5.00%. When the Cu-based alloy contains Si, P, and S as unavoidable impurities, the contents are preferably Si: 0.20% or less, P: 0.10% or less, and S: 0.10% or less.

[0027] This Cu-based alloy powder can achieve high laser light absorption without requiring a special oxidation treatment to form an oxide film. Therefore, the powder particles made of this Cu-based alloy can be rapidly melted even by laser irradiation with a low energy density. Therefore, this Cu-based alloy powder can obtain a high-density shaped body by additive manufacturing without causing bumping of the molten metal. Furthermore, this Cu-based alloy powder can also provide the effect of suppressing oxidation due to changes over time during storage. Therefore, by using this Cu-based alloy powder as a material for additive manufacturing, a shaped body having desired characteristics can be stably manufactured at a high density. The reasons for specifying each component of the Cu-based alloy powder are as follows.

[0028] [Cr:0.10~1.00%] In a Cu-based alloy containing Cr, Cr dissolves in Cu to form a solid solution. In this solid solution, the laser reflectance is suppressed. When a particle made of a Cu-based alloy containing Cr is irradiated with a laser, the heat is efficiently absorbed and an oxide containing Cr is generated. Therefore, the Cr content in this Cu-based alloy is set to 0.10 to 1.00%. From the viewpoint of facilitating the formation of an oxide layer, the Cr content is preferably 0.15% or more. From the viewpoint of not impairing the electrical conductivity of the resulting shaped body, the Cr content is preferably 0.50% or less.

[0029] [Nd, Gd, Dy and Y, either one or more of these, 0.10 to 5.00% in total] The standard energy of formation of oxides of Nd, Gd, Dy and Y is lower than that of Cr. In the particles made of a Cu-based alloy containing Cr and one or more selected from the group consisting of Nd, Gd, Dy and Y, the generation of oxides is promoted by laser irradiation, and an oxide layer coating is quickly formed on the surface without the need for a special separate processing step. At that time, the oxide layers of Nd, Gd, Dy and Y contribute to further improvement of the laser light absorption rate in combination with the Cr oxide. Nd, Gd, Dy and Y also contribute to improvement of the adhesion and stability of the formed oxide layer. Therefore, the total content of Nd, Gd, Dy and Y in this Cu-based alloy is 0.10 to 5.00%. From the viewpoint of the formation and adhesion of the oxide layer, the preferred total content is 0.15% or more. From the viewpoint of handling and safety during production, the preferred total content is 3.0% or less.

[0030] [Si (silicon), P (phosphorus) and S (sulfur)] In the Cu-based alloy powder used in the present invention, Si, P, and S are all unavoidable impurities. The content of each of these impurities is preferably within the following range. Note that none of Si, P, or S may be contained at all in the Cu-based alloy powder. Si:0~0.20% or less P:0~0.100% or less S:0~0.100% or less

[0031] Si is an inevitable impurity. Si dissolves in Cu and inhibits electrical conduction and thermal conduction of the Cu-based alloy. Therefore, the content of Si as an inevitable impurity is preferably 0.20% or less, more preferably 0.10% or less, and even more preferably 0.05% or less. Furthermore, the content of Si may be 0.

[0032] P is an inevitable impurity. P dissolves in Cu and inhibits electrical conduction and thermal conduction of the Cu-based alloy. Therefore, the content of P as an inevitable impurity is preferably 0.100% or less, more preferably 0.010% or less, and even more preferably 0.005% or less. Furthermore, the content of P may be 0.

[0033] S is an inevitable impurity. S dissolves in Cu and inhibits electrical conduction and thermal conduction of the Cu-based alloy. Therefore, the content of S as an inevitable impurity is preferably 0.100% or less, more preferably 0.010% or less by mass, and particularly preferably 0.005% or less. Furthermore, the content of S may be 0.

[0034] [O(oxygen)] The Cu-based alloy powder may contain O as an inevitable impurity. O may generate oxides of the above-mentioned elements during the production and storage of the alloy powder. In particular, the oxides generated during storage may change the laser absorption rate, thereby reducing the manufacturing stability during additive manufacturing. Therefore, the oxygen content in the Cu-based alloy powder is preferably 1000 ppm or less, more preferably 500 ppm or less. The lower the oxygen content, the more preferable it is, and the lower limit is not particularly limited.

[0035] [D 50 / TD:0.2×10 -5 ~20×10 -5 m 4 / Mg] In this Cu-based alloy powder, the average particle diameter D 50 (μm) and its tap density TD (Mg / m 3 ) and "D 50 / TD" is 0.2 x 10 -5 ~20×10 -5 m 4 / Mg is preferred. This ratio "D 50 / TD" is 0.2 x 10 -5 m 4 The alloy powder having a ratio of D / Mg or more has excellent flowability. 50 / TD" is 0.5 x 10 -5 m4 / Mg or more, and the more preferable ratio is 5.0×10 -5 m 4 / Mg or more. Ratio "D" 50 / TD" is 20 x 10 -5 m 4 If the ratio exceeds 1 / Mg, the resulting body tends to have a low relative density. 50 / TD" is 20 x 10 -5 m 4 More preferably, the ratio D 50 / TD is 18×10 -5 m 4 / Mg or less. More preferably, it is 15×10 -5 m 4 / Mg or less.

[0036] [Cu-based alloy powder average particle size D 50 ] The ratio D mentioned above 50 As long as the specified value of / TD is satisfied, the average particle diameter D of the alloy powder is 50 The numerical range of the alloy powder itself is not particularly limited, but from the viewpoint of fluidity, the average particle diameter D 50 is preferably 15 μm or more, more preferably 20 μm or more, and even more preferably 25 μm or more. On the other hand, from the viewpoint of increasing the density of the molded body, the average particle diameter D 50 is preferably 50 μm or less, more preferably 40 μm or less, and particularly preferably 30 μm or less.

[0037] Average particle diameter D 50 In the measurement of the average particle diameter D, the total volume of the alloy powder is taken as 100%, and a cumulative curve is obtained. The particle diameter (median diameter) at the point on this curve where the cumulative volume is 50% is the average particle diameter D. 50 The average particle size D 50can be measured by the laser diffraction scattering method. A suitable device for this measurement is the Microtrac MT3000 laser diffraction / scattering particle size distribution analyzer from Nikkiso Co., Ltd. In this device, alloy powder is poured into the device's cell together with pure water, and the particle size is detected based on the light scattering information of the particles.

[0038] [Tap density TD of Cu-based alloy powder] The ratio D mentioned above 50 As long as / TD satisfies a predetermined value, the tap density TD of the alloy powder itself is not particularly limited. However, from the viewpoint of ease of manufacturing a shaped body, the tap density TD of this alloy powder is preferably 0.10 Mg / m 3 More than 0.40Mg / m 3 Less than 0.15Mg / m is preferable. 3 More than 0.35Mg / m 3 The following are particularly preferred:

[0039] The tap density TD is measured in accordance with the standard of "JIS Z2512". In the measurement, about 50 g of alloy powder is filled into a cylinder with a volume of 100 cm3, and the tap density is measured. The measurement conditions are as follows: Drop height: 10mm Number of taps: 200

[0040] [Sphericity of Cu-based alloy powder: 0.80~0.95] The sphericity of this Cu-based alloy powder is preferably 0.80 or more and 0.95 or less. An alloy powder having a sphericity of 0.80 or more has excellent flowability. From this viewpoint, the sphericity is more preferably 0.83 or more, and particularly preferably 0.85 or more. In an alloy powder having a sphericity of 0.95 or less, reflection of a laser can be suppressed. From this viewpoint, the sphericity is more preferably 0.93 or less, and particularly preferably 0.90 or less.

[0041] For the measurement of sphericity, a test specimen is prepared by embedding Cu-based alloy powder in resin. The test specimen is mirror-polished, and the polished surface is observed under an optical microscope. The magnification of the microscope is 100 times. Image analysis is performed on 20 randomly selected alloy particles, and the sphericity of the alloy particles is measured. The sphericity of an alloy particle is the ratio of the length in the direction perpendicular to the longest line that can be drawn within the outline of the alloy particle to the length of the longest line. The average of the 20 measurements is the sphericity of the alloy powder.

[0042] [Laser light absorption rate of Cu-based alloy powder] As described above, the Cu-based alloy powder according to the present invention has a high laser light absorptivity. In a laser-type metal additive manufacturing machine, a YAG laser with a wavelength of 1064 nm or a fiber laser with a wavelength of about 1000 to 1100 nm is widely used. From the viewpoint of obtaining a shaped body by additive manufacturing, it is preferable that the Cu-based alloy powder has a high laser light absorptivity. Therefore, the Cu-based alloy powder preferably has a laser light absorptivity of 30% or more at a wavelength of 1064 nm. More preferably, the laser light absorptivity of 50% or more at a wavelength of 1064 nm. A method for measuring the laser light absorptivity will be described later in the examples.

[0043] [Precipitate size: 20μm or less] As a characteristic of a shaped body made of a Cu-based alloy produced by additive manufacturing using a Cu-based alloy powder, the size of precipitates in the Cu-based alloy is set to 20 μm or less. In Cu-based alloys, when the additive elements are dissolved in the copper matrix, they impede thermal conduction. When Cu-based alloys are manufactured using Cu-based alloy powder by additive manufacturing, the additive elements are expelled from the copper matrix as precipitates by aging heat treatment of the manufactured body, and the thermal conductivity of copper can be restored. However, if the precipitates (additive elements alone or intermetallic compounds of copper and the added elements) that are discharged are too large, they will block the paths for thermal conduction, so the size of the precipitates in the Cu-based alloy in the shaped body made of the Cu-based alloy is set to 20 μm or less.

[0044] [Manufacturing method of Cu-based alloy powder] The manufacturing method of the Cu-based alloy powder is not particularly limited, and examples thereof include water atomization, gas atomization, disk atomization, and centrifugal atomization. Preferred manufacturing methods are gas atomization and disk atomization. The Cu-based alloy powder may be subjected to mechanical milling, etc. Examples of milling methods include ball milling, bead milling, planetary ball milling, attritor method, and vibration ball milling.

[0045] [molding] The Cu-based alloy powder according to the present invention can be used to obtain shaped bodies of various shapes by additive manufacturing. A 3D printer can be used for the additive manufacturing method. In this additive manufacturing method, for example, in the powder bed method, a laser beam or an electron beam is irradiated onto an area where Cu-based alloy powder is spread. The irradiation causes the alloy particles in the irradiated area to heat up and melt rapidly. The alloy particles then solidify rapidly. This melting and solidification causes the alloy particles in the irradiated area to bond together. Irradiation is selectively performed on a portion of the alloy powder. The parts of the alloy powder that are not irradiated do not melt. A bonding layer made of Cu-based alloy is formed only in the irradiated area.

[0046] A Cu-based alloy powder is further spread on the bonding layer. A laser beam or an electron beam is irradiated onto this alloy powder. The irradiation causes the Cu-based alloy particles to melt rapidly. The alloy particles then rapidly solidify. This melting and solidification bonds the Cu-based alloy particles in the Cu-based alloy powder together, forming a new Cu-based alloy bonding layer. The new bonding layer also bonds with the existing bonding layer.

[0047] By repeating the bonding by irradiation, an aggregate of bonding layers made of Cu-based alloy gradually grows. This growth results in a shaped body made of Cu-based alloy with a three-dimensional shape. In other words, by using the additive manufacturing method in which the irradiation position is set in advance and additive manufacturing is repeated, it is possible to easily obtain a shaped body with a complex shape.

[0048] [Modeling conditions] The molding conditions are appropriately selected depending on the physical properties of the Cu-based alloy powder, the composition of the Cu-based alloy, etc., but the preferred energy density ED is 100 to 350 J / mm 3 The energy density ED is 100 J / mm 3 If the energy density ED is 120 J / mm or more, sufficient heat is applied to the alloy powder, so that the unmelted alloy powder is prevented from remaining inside the shaped body. In addition, since it is desirable for the relative density of the shaped body to be large, it is more preferable that the energy density ED is 120 J / mm 3 More preferably, the energy density ED is 140 J / mm 3 That's all. On the other hand, the energy density ED is 350 J / mm 3 If the energy density exceeds 350 J / mm, excessive heat will be applied to the Cu-based alloy powder. 3 It is preferable that the energy density ED is 300 J / mm or less. By suppressing the bumping of the molten metal, the generation of voids inside the shaped body is suppressed. Therefore, it is more preferable that the energy density ED is 300 J / mm 3 More preferably, the energy density ED is 250 J / mm 3 The following is the result.

[0049] Relative Density The relative density of the Cu-based alloy shaped body obtained by the additive manufacturing method (i.e., the shaped body before the heat treatment described below) is preferably 90% or more. If the relative density of this unheat-treated shaped body is high, it will have excellent dimensional accuracy and electrical conductivity. Therefore, the relative density is more preferably 93% or more, and particularly preferably 95% or more.

[0050] The relative density of the molded body is calculated based on the ratio of the density of a 10 mm square test piece produced by the additive manufacturing method to the theoretical density of the raw alloy powder. The density of the 10 mm square test piece is measured by the Archimedes method. The theoretical density of the alloy powder is calculated from the theoretical density of each element that constitutes the alloy. For example, in the case of a Cu-based alloy consisting of 99% by mass of Cu and 1% by mass of Cr, the theoretical density of the alloy powder is calculated based on the following formula. Theoretical density of alloy powder (g / cm 3 ) = theoretical density of Cu (g / cm 3 )×0.99+Cr theoretical density (g / cm 3 )×0.01

[0051] [Electrical conductivity of the model] The electrical conductivity of the shaped body (i.e., the shaped body before the heat treatment described below) is preferably 50 IACS% or more, and more preferably 80 IACS% or more. The method and conditions for measuring the electrical conductivity will be described later in the Examples.

[0052] [Heat treatment] The molded body obtained by the additive manufacturing method is subjected to a heat treatment as necessary. A preferred heat treatment is an aging treatment. The aging treatment improves the electrical conductivity of the molded body.

[0053] [Heat treatment conditions] In the aging treatment, the untreated shaped body is held at a predetermined temperature for a predetermined time. From the viewpoint of improving electrical conductivity, the aging temperature is preferably 350° C. or higher, more preferably 400° C. or higher, and particularly preferably 450° C. or higher. Similarly, from the viewpoint of electrical conductivity, the aging temperature is preferably 1000° C. or lower, more preferably 950° C. or lower, and particularly preferably 900° C. or lower.

[0054] From the viewpoint of improving electrical conductivity, the aging treatment time is preferably 1 hour or more, more preferably 1.3 hours or more, and particularly preferably 1.5 hours or more, whereas from the viewpoint of energy cost, the aging time is preferably 10 hours or less, more preferably 9.7 hours or less, and particularly preferably 9.5 hours or less.

[0055] Hereinafter, an embodiment of a shaped body made of a Cu-based alloy formed by additive manufacturing using a Cu-based alloy powder will be described with reference to examples, and the effects of the present invention will be shown. However, it should be noted that the present invention should not be interpreted in a limited manner based on the description of the examples.

[0056] [Production of Cu-based alloy powder] In a vacuum, raw materials having compositions shown in Tables 1 and 2 for Examples 1 to 22 and Comparative Examples 1 to 10 were heated and melted by high-frequency induction heating in an alumina crucible. The molten metal was taken out from a nozzle having a diameter of 5 mm provided at the bottom of the crucible. Argon gas was sprayed into the molten metal, and a large number of particles were obtained by a gas atomization method. These particles were classified to remove particles having a diameter of more than 63 μm, thereby obtaining Cu-based alloy powders for Examples 1 to 22 and Comparative Examples 1 to 10. Tables 1 and 2 show the ratios of D 50 / TD" and sphericity.

[0057] [Oxygen content] The oxygen content (ppm by mass) of the Cu-based alloy powders of the examples and comparative examples was quantified by a combustion method in accordance with the provisions of JIS Z2613 "General rules for the determination of oxygen in metallic materials." The combustion method is a method in which a sample is heated in a graphite crucible, the amount of CO gas generated is measured by a non-dispersive infrared absorption method, and the amount of oxygen contained in the sample is measured. The oxygen content (ppm by mass) of the Cu-based alloy powders of the examples and comparative examples was measured. For the measurement, an oxygen / nitrogen analyzer (Horiba Ltd., product name "EMGA-620W") was used. The measurement results are shown in Tables 1 and 2.

[0058] [Laser light absorption measurement] For the Cu-based alloy powders of the examples and comparative examples, the total reflectance (%) at a wavelength of 1064 nm was measured using an ultraviolet-visible-near infrared spectrophotometer (manufactured by JASCO Corporation under the trade name "V-770DS"), and the laser light absorptance (%) was calculated using the following formula. Laser light absorption rate (%) = 100 - total reflectance rate (%) The results obtained are shown in Tables 1 and 2.

[0059] [molding] The Cu-based alloy powders of the examples and comparative examples were used as raw materials, and additive manufacturing was carried out using a 3D additive manufacturing device (EOS Corporation's product name "EOS-M280") to obtain shaped bodies (unheat-treated shaped bodies). The energy density ED (J / mm3) in the additive manufacturing method is shown in Tables 1 and 2. The shapes of the shaped bodies were all cubes with sides of 10 mm. The relative densities (%) of the obtained shaped bodies, measured by the above-mentioned method, are shown in Tables 1 and 2.

[0060] [Measurement of electrical conductivity] The Cu-based alloy powders of the examples and comparative examples were each arc-melted to obtain an ingot. The obtained ingot was cut to prepare a plate-shaped test piece (3×2×60 mm), and the electrical resistance value (Ω) was measured by the four-terminal method in accordance with "JIS C 2525". For the measurement, an ULVAC-RIKO Corporation device "TER-2000RH type" was used. The measurement conditions were as follows. Temperature: 25℃ Current: 4A Voltage drop distance: 40mm The electrical resistivity ρ (Ωm) was calculated based on the following formula. ρ=R / I×S In this formula, R is the electrical resistance value (Ω) of the test piece, I is the current (A), and S is the cross-sectional area (m2) of the test piece. The electrical conductivity (S / m) was calculated from the reciprocal of the electrical resistivity ρ. In addition, the electrical conductivity (%IACS) of each test piece was calculated by assuming 5.9×107 (S / m) to be 100% IACS. The results are shown in Tables 1 and 2.

[0061] [Rating 1] Based on the laser light absorptance obtained by measuring each alloy powder, the alloy powders were ranked according to the following criteria. Evaluation score 1: Laser light absorption rate is 50% or more. Evaluation value 2: Laser light absorptance is 30% or more and less than 50%. Evaluation score 3: Laser light absorption rate is less than 30%. The results are shown in Tables 1 and 2. A rating of 1 is the best, and a rating of 3 is poor.

[0062] [Rating 2] According to the findings of the inventors, the electrical conductivity obtained by using the above-mentioned ingot correlates with the electrical conductivity of the molded body obtained by the additive manufacturing method. In addition, according to the Wiedemann-Franz law, the thermal conductivity of a metal is proportional to its electrical conductivity. Therefore, by confirming the electrical conductivity, which is easy to measure, the thermal conductivity characteristics can also be evaluated. Therefore, based on the electrical conductivity determined by the above measurement method, the shaped bodies were graded according to the following criteria. Evaluation score 1: Electrical conductivity is 80% IACS or more. Evaluation value 2: Electrical conductivity is 50% IACS or more and less than 80% IACS. Evaluation score 3: Electrical conductivity is less than 50% IACS. The results are shown in Tables 1 and 2. A rating of 1 is the best, and a rating of 3 is poor.

[0063] [Table 1]

[0064] [Table 2]

[0065] The notation "-" in the composition of the Cu-based alloy powders in Tables 1 and 2 means that the corresponding component was not detected.

[0066] As shown in Tables 1 and 2, the Cu-based alloy powders of the examples were rated higher than the alloy powders of the comparative examples, and the objects fabricated by additive manufacturing using the powders of the examples also had high electrical conductivity, clearly demonstrating the superiority of the objects fabricated based on the examples of the present invention.

[0067] In Comparative Examples 1 to 4, the Cr content was too small, resulting in poor laser light absorption and a relatively low relative density of the shaped bodies. In Comparative Examples 5 to 8, the total amount of Nd, Gd, Dy, and Y was too small, resulting in poor laser light absorptance or poor conductivity. In Comparative Examples 9 and 10, the total amount of Nd, Gd, Dy, and Y was excessive, and the precipitate size was excessively large, resulting in poor conductivity.

Claims

1. In mass percent, Cr: 0.10 to 1.00%; Contains one or more of Nd, Gd, Dy and Y in total in an amount of 0.10 to 5.00%; The remainder is made of Cu and unavoidable impurities, and the layered manufacturing is performed using a Cu-based alloy powder having a laser light absorption rate of 35 to 53% at a wavelength of 1064 nm. A shaped body made of a Cu-based alloy having an electrical conductivity of 50 to 86% IACS and a precipitate size of 20 μm or less.

2. A shaped body made of a Cu-based alloy having a precipitate size of 20 μm or less, which is layer-by-layer manufactured using the Cu-based alloy powder according to claim 1, wherein the Si, P, and S in the unavoidable impurities are Si: 0.20% or less, P: 0.100% or less, and S: 0.100% or less.

3. Average particle diameter D 50 (μm) and tap density TD (Mg / m 3 ) and D 50 / TD value is 0.2 × 10 -5 ~20 x 10 -5 ・m 4 3. A shaped body made of a Cu-based alloy having a precipitate size of 20 μm or less, which is produced by layered manufacturing using the Cu-based alloy powder according to claim 1 or 2, wherein the Cu-based alloy powder has a sphericity of 0.80 to 0.95 and a molecular weight of 1.0 to 1.0 Mg.

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