Copper alloy powder, method for manufacturing the same, copper alloy device, and method for manufacturing the same

Abstract

The application provides a copper alloy powder and a preparation method thereof, and a copper alloy device and a preparation method thereof. The copper alloy powder comprises the following components in mass fraction: Cr 1.5-4.0%, Zr 0-0.4%, and the balance of Cu and inevitable impurities. The copper alloy powder comprises a copper matrix, and Cr particles and optional CuZr particles enriched on the surface of the copper matrix, wherein the average size of the Cr particles and the CuZr particles is 30-500 nm. By selecting specific copper alloy components, the application controls the Cr and CuZr to be enriched in the form of particles on the surface of the copper matrix, and controls the average size of the particles, so that the reflectivity of the powder to infrared laser is greatly reduced, a stable and continuous molten pool can be formed in the printing process, the density of the printed part is improved, and the application potential of the Cr and CuZr precipitated phases enriched in the copper matrix is expanded under normal temperature and high-temperature working conditions.

Description

Technical Field

[0001] This application relates to the fields of metallic materials and additive manufacturing, and more specifically, to a copper alloy powder and its preparation method, and a copper alloy device and its preparation method. Background Technology

[0002] CuCrZr is a typical high-strength, high-conductivity copper alloy. Due to its high strength, excellent electrical and thermal conductivity, and corrosion resistance, it is widely used in integrated circuit lead frames, rocket engine combustion chambers, high-speed rail contact lines, and high-efficiency heat dissipation components. The development of additive manufacturing technologies such as laser powder bed fusion (L-PBF) allows for the direct forming of functionally integrated parts with complex internal flow channels and lightweight lattice structures, opening up new pathways for the synergistic optimization of the form and properties of copper alloy devices.

[0003] However, CuCrZr alloy powders, represented by C18150 (Cr content 0.1~1.0wt%, Zr content 0~0.1wt%), face two major challenges in L-PBF technology applications: First, the high laser reflectivity. Due to the low Cr and Zr content in traditional copper alloys, their effect on improving the laser absorption capacity of the copper matrix is ​​limited. The powder has extremely high reflectivity to infrared wavelength lasers, making it difficult to form a stable and continuous molten pool during the printing process. This easily leads to incomplete fusion, spheroidization, and porosity defects, severely restricting the density and mechanical properties of the formed parts. Second, insufficient mechanical properties at both room temperature and high temperature. The strengthening phases of traditional copper alloys formed by L-PBF technology mainly rely on precipitates formed by the limited solid solution of Cr and Zr elements in the copper matrix. At high temperatures, these strengthening phases are prone to coarsening or dissolution, resulting in a significant decline in the alloy's high-temperature strength, hardness, and creep resistance, limiting its application potential under high-temperature conditions.

[0004] In view of the above, this application is hereby submitted. Summary of the Invention

[0005] The main objective of this application is to provide a copper alloy powder and its preparation method, as well as a copper alloy device and its preparation method, to solve the problems of high laser reflection and insufficient mechanical properties at room temperature and high temperature of traditional CuCrZr alloy powder.

[0006] To achieve the above objectives, according to a first aspect of this application, a copper alloy powder is provided, comprising the following components by mass fraction: Cr 1.5~4.0%, Zr 0~0.4%, with the balance being Cu and unavoidable impurities; the copper alloy powder includes a copper matrix, and Cr particles and optional CuZr particles enriched on the surface of the copper matrix, wherein the average size of the Cr particles and CuZr particles is 30~500 nm, respectively.

[0007] Furthermore, the mass fraction of Cr component in the copper alloy powder is 2.5~4%.

[0008] Furthermore, the copper alloy powder has a laser reflectivity of 40-65% in the near-infrared light band.

[0009] According to a second aspect of this application, a method for preparing copper alloy powder is provided, comprising the following steps:

[0010] S1. Weigh the raw materials according to the mass fraction of the components of the copper alloy powder and mix them. Then, perform sintering and gas atomization treatment in sequence to obtain the alloy powder.

[0011] S2, the raw material alloy powder is heat-treated to obtain the copper alloy powder.

[0012] Further, Cr powder and CuZr alloy powder are mixed and ball-milled to obtain ball-milled alloy powder. The ball-milled alloy powder is then mixed with copper powder and vacuum sintered to obtain an alloy billet. The alloy billet is then subjected to gas atomization treatment to obtain raw material alloy powder. The copper powder is spherical copper powder or electrolytic copper powder with a purity ≥99.9% and an average particle size of 15~300μm.

[0013] Furthermore, the purity of the Cr powder is ≥99%, and the average particle size of the Cr powder is 3~50μm.

[0014] Furthermore, in the CuZr alloy powder, the Zr mass content is 5%~50%, the impurity content is ≤1%, and the average particle size of the CuZr alloy powder is 3~80μm.

[0015] Furthermore, the heat treatment is carried out in a mixed atmosphere of protective and reducing gases.

[0016] Furthermore, the protective gas includes at least one of nitrogen, argon, or helium.

[0017] Furthermore, the reducing gas is at least one of hydrogen and carbon monoxide.

[0018] Furthermore, in the mixture of protective gas and reducing gas, the volume ratio of protective gas to reducing gas is (200~2000):(20~200).

[0019] Furthermore, the heat treatment temperature is 550~750℃, and the heat treatment time is 30~120min.

[0020] According to a third aspect of this application, a copper alloy device is provided, wherein the material of the copper alloy device is the copper alloy powder provided in the first aspect of this application or the copper alloy powder prepared by the preparation method provided in the second aspect of this application.

[0021] According to the fourth aspect of this application, a method for preparing a copper alloy device is provided, the method comprising: adding copper alloy powder into a 3D printer to print a 3D printed device, and subjecting the 3D printed device to aging treatment to obtain a copper alloy device; wherein the copper alloy powder is the copper alloy powder provided in the first aspect of this application or the copper alloy powder obtained by the preparation method provided in the second aspect of this application, preferably the average particle size of the copper alloy powder is 15~53μm.

[0022] Furthermore, laser powder bed fusion printing is used, wherein the laser power is 300~500W, the scanning speed is 400~1200mm / s, the processing layer thickness is 0.03~0.06mm, and the scanning spacing is 0.05~0.15mm.

[0023] Furthermore, the aging treatment temperature is 450~600℃.

[0024] Furthermore, the aging treatment temperature is 500~600℃.

[0025] Furthermore, the processing time is 30~360 minutes.

[0026] By applying the technical solution of this application, by selecting specific copper alloy components, controlling Cr and CuZr to be enriched in the form of particles on the surface of the copper matrix, and controlling the average particle size to be 30~500nm, the copper alloy powder not only significantly reduces the reflectivity of infrared lasers, but also forms a stable and continuous molten pool during the printing process, improving the density of the printed parts. Furthermore, the copper matrix is ​​enriched with a large number of Cr and CuZr particles as precipitates, expanding its application potential under high-temperature conditions.

[0027] The copper alloy device provided in this application uses the aforementioned copper alloy powder as raw material and has low laser reflection, excellent high-temperature electrical and thermal conductivity, and mechanical properties, and has broad application prospects in aerospace, electronic information and other fields. Attached Figure Description

[0028] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0029] Figure 1 A scanning electron microscope image of copper alloy powder prepared according to Example 1 of this application is shown.

[0030] Figure 2 A scanning electron microscope image of the copper alloy powder prepared according to Example 5 of this application is shown.

[0031] Figure 3A scanning electron microscope image of the weld seam of a copper alloy device prepared according to Example 15 of this application is shown.

[0032] Figure 4 A cross-sectional optical microscope image of a copper alloy device prepared according to Example 16 of this application is shown.

[0033] Figure 5 A cross-sectional microstructure of a copper alloy device prepared according to Example 17 of this application is shown. Detailed Implementation

[0034] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present application will now be described in detail with reference to the embodiments.

[0035] As described in the background section of this application, traditional CuCrZr alloy powders suffer from high laser reflection and insufficient mechanical properties at high temperatures. To address at least one of these problems, this application provides a copper alloy powder and its preparation method, as well as a copper alloy device and its preparation method.

[0036] In a first typical embodiment of this application, a copper alloy powder is provided, which comprises the following components by mass fraction: Cr 1.5~4.0%, Zr 0~0.4%, with the balance being Cu and unavoidable impurities; the copper alloy powder includes a copper matrix, and Cr particles and optional CuZr particles enriched on the surface of the copper matrix, wherein the average size of the Cr particles and CuZr particles is 30~500 nm.

[0037] In the copper alloy powder provided in this application, the amount of Cr added is controlled at 1.5~4.0%, and the amount of Zr added is controlled at 0~0.4%, which is beneficial to improving its laser absorption capacity. In addition, it is also beneficial to maintain the original sphericity of the copper powder so that it has good powder spreading performance, ensuring a smooth printing process and high quality of printed products.

[0038] In the copper alloy powder provided in this application, Cr and Zr elements are enriched on the surface of the copper matrix in the form of dispersed phases, and the sizes of Cr and CuZr particles are independently 30~500nm, which can effectively enhance the laser capability of the copper powder and improve the energy utilization rate during the printing process. In addition, the appropriate particle size of Cr and CuZr particles can scatter the laser, further improving the laser absorption efficiency of the copper powder. Furthermore, controlling the size of Cr and CuZr particles to 30~500nm allows for more effective melting during the printing process and nanoscale precipitation during subsequent aging treatment, thereby improving the mechanical properties of the device.

[0039] The copper alloy powder provided in this application can improve the laser absorption capacity of copper powder without affecting its sphericity and powder spreading characteristics, thereby enabling the high reflectivity copper powder to be effectively melted in the additive manufacturing process to form high-density and high-precision copper devices. On the other hand, by increasing the content of Cr and Zr elements, the number density of nano-precipitated phases in the copper matrix is ​​increased, thereby significantly improving the mechanical properties of the device.

[0040] Furthermore, the copper alloy powder provided in this application not only effectively solves the problem of high laser reflectivity faced by traditional copper alloy powder in additive manufacturing technology applications, but also optimizes the high-temperature mechanical properties of copper alloy printed devices, demonstrating the broad application prospects of copper alloy powder in the field of additive manufacturing.

[0041] In some specific embodiments, the mass fraction of Cr element in the copper alloy powder is any value or a range between any two of 1.5%, 1.6%, 1.8%, 2.0%, 2.2%, 2.5%, 2.8%, 3.0%, 3.2%, 3.5%, and 4%; and the mass fraction of Zr element is any value or a range between any two of 0%, 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, and 0.4%.

[0042] In some specific embodiments, the sizes of Cr particles and Zr particles are each independently 30 nm, 50 nm, 56 nm, 100 nm, 125 nm, 150 nm, 155 nm, 160 nm, 165 nm, 168 nm, 170 nm, 172 nm, 173 nm, 175 nm, 178 nm, 180 nm, 182 nm, 183 nm, 185 nm, 187 nm, 189 nm, 190 nm, 195 nm, 198 nm, 200 nm, 300 nm, 400 nm, 500 nm, or any value or a range between any two.

[0043] In some embodiments, the laser reflectivity of the copper alloy powder in the near-infrared band is 40%–65%. Cr and Zr elements have high laser absorption coefficients, and Cr and Zr elements are enriched on the surface of the copper matrix in the form of dispersed phases. This increases the interaction between the copper alloy powder and the laser, further reducing the reflectivity of the copper alloy powder to near-infrared laser light and further improving the effective utilization of laser energy. Specifically, the laser reflectivity of the copper alloy powder in the near-infrared band is any value from 40%, 45%, 50%, 55%, 60%, and 65%, or any value between any two.

[0044] In a second typical embodiment of this application, a method for preparing copper alloy powder is provided, the method comprising:

[0045] Step S1: Weigh the raw materials according to the mass fraction of the components of the copper alloy powder, mix them, and then perform sintering and gas atomization treatment in sequence to obtain the raw material alloy powder.

[0046] Step S2: Heat-treat the raw material alloy powder to obtain copper alloy powder.

[0047] The method for preparing copper alloy powder provided in this application enables Cr and optional Zr elements to be partially enriched in the form of dispersed phases on the surface of the copper matrix through sintering, and makes the average size of Cr particles and Zr particles independently 30~500nm, which further reduces the reflectivity of the copper alloy powder to laser, thereby improving the laser absorption efficiency of the copper alloy powder in the additive manufacturing process.

[0048] In some embodiments, the preparation method includes: mixing Cr powder and CuZr alloy powder and ball milling to obtain ball-milled alloy powder; mixing the ball-milled alloy powder and copper powder and vacuum sintering to obtain alloy rod blank; and subjecting the alloy rod blank to gas atomization treatment to obtain alloy powder.

[0049] The copper powder is either spherical or electrolytic, with a purity of ≥99.9% and an average particle size of 15~300μm.

[0050] As mentioned earlier, by mixing Cr powder and CuZr alloy powder and ball milling, the Cr powder and CuZr alloy powder are mixed more evenly in the ball-milled alloy powder. The ball-milled alloy powder is then mixed with copper powder and vacuum sintered to obtain an alloy rod blank, so that the elements in the alloy rod blank are mixed more evenly. Then, the alloy rod blank is subjected to gas atomization treatment to obtain alloy powder.

[0051] In some embodiments, the copper powder is spherical copper powder or electrolytic copper powder, the purity of the copper powder is ≥99.9%, and the average particle size of the copper powder is 15~300 μm. Limiting the purity and average particle size of the copper powder is beneficial for further preparing copper alloy powder with uniform composition. Specifically, the average particle size of the copper powder is any value or a range between 15 μm, 20 μm, 30 μm, 50 μm, 100 μm, 200 μm, and 300 μm.

[0052] In some embodiments, the purity of Cr powder is ≥99%, and the average particle size of Cr powder is 3~50 μm. The purity of Cr powder can further improve the absorption efficiency and purity of alloying elements, thereby effectively promoting the uniform distribution of Cr elements on the surface of the copper matrix and promoting the stable precipitation of Cr particles, thus enhancing the laser absorption performance of the copper alloy powder. Controlling the average particle size of Cr powder to 3~50 μm is beneficial for thorough mixing with copper powder during ball milling, and during sintering, Cr is enriched on the surface of copper powder in the form of finer particles, further improving laser reflectivity. Specifically, the average particle size of Cr powder is any value or a range between 3μm, 10μm, 20μm, 30μm, 40μm, and 50μm.

[0053] In some embodiments, the Zr content in the CuZr alloy powder is 5%~50% by mass, the impurity content is ≤1% by mass, and the average particle size of the CuZr alloy powder is 3~80μm. Using CuZr alloy powder as a raw material to introduce Zr facilitates the uniform distribution of Zr in the copper alloy powder, further promoting the formation of the Zr dispersed phase, thereby enhancing the high-temperature performance and electrical and thermal conductivity of the copper matrix. Simultaneously, controlling the particle size of the CuZr alloy powder can prevent burn-off during alloy atomization, facilitating composition control. Specifically, the Zr content is any value or a range between 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, and 50% by mass; the average particle size of the CuZr alloy powder is any value or a range between 3μm, 5μm, 10μm, 20μm, 40μm, 60μm, and 80μm.

[0054] In some embodiments, the vacuum sintering temperature is 750~950℃, the vacuum sintering time is 1~3h, and the vacuum sintering pressure is 20~80MPa, so as to improve the vacuum sintering efficiency while making the ball-milled alloy powder more uniformly mixed. Specifically, the vacuum sintering temperature is any value or a range between 750℃, 800℃, 850℃, 900℃, and 950℃; the vacuum sintering time is any value or a range between 1h, 2h, and 3h; and the vacuum degree is any value or a range between 20MPa, 30MPa, 40MPa, 50MPa, 60MPa, 70MPa, and 80MPa.

[0055] In some embodiments, the pressure of the gas atomization treatment is 1~6 MPa, and the temperature is 1150~1300℃, to facilitate obtaining alloy powder of suitable size. Specifically, the pressure of the gas atomization treatment is any value or a range of any two values ​​from 1 MPa, 2 MPa, 3 MPa, 4 MPa, 5 MPa, and 6 MPa, and the temperature of the gas atomization treatment is any value or a range of any two values ​​from 1150℃, 1200℃, 1250℃, and 1300℃.

[0056] In some embodiments, the heat treatment is carried out in a mixed atmosphere of protective and reducing gases, which can further prevent the oxidation of the alloy powder at high temperatures.

[0057] In some specific embodiments, the protective gas is any one or more of nitrogen, argon, or helium.

[0058] In some specific embodiments, the reducing gas is any one or more of hydrogen and carbon monoxide.

[0059] In some embodiments, the volume ratio of the protective gas to the reducing gas in the mixture of protective gas and reducing gas is (200~2000):(20~200). This mixed gas can effectively reduce the oxides on the surface of the alloy powder while avoiding the waste of excessive reducing gas. Specifically, the volume ratio of the protective gas to the reducing gas is any value from 200:20, 200:50, 200:100, 200:200, 500:20, 500:50, 500:100, 500:200, 1000:20, 1000:50, 1000:100, 1000:200, 2000:20, 2000:50, 2000:100, 2000:200, or a range between any two.

[0060] In some embodiments, the heat treatment temperature is 550–750 °C, and the heat treatment time is 30–120 min. Suitable heat treatment temperature and time can further promote the precipitation of Cr and Zr elements as dispersed phases on the copper matrix surface, forming Cr particles and CuZr particles with a size of 30–500 nm. Selecting the above sintering temperature based on the diffusion rate of alloying elements is more conducive to promoting the enrichment of Cr and Zr elements on the surface in the form of Cr particles and CuZr particles, further improving the fluidity of the copper alloy powder. Controlling the sintering time can further promote the diffusion of Cr and Zr elements to the copper matrix surface, increasing the content of Cr and Zr particles, thereby further improving the laser absorption rate, while avoiding changes in copper powder particle size caused by prolonged high-temperature treatment.

[0061] In some specific embodiments, the heat treatment temperature is any value of 550°C, 600°C, 650°C, 700°C, 750°C or a range between any two; the heat treatment time is any value of 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, 90 min, 100 min, 110 min, 120 min or a range between any two.

[0062] In a third typical embodiment of this application, a copper alloy device is provided. The material of the copper alloy device is the copper alloy powder provided in the first typical embodiment or the copper alloy powder prepared by the preparation method provided in the second typical embodiment.

[0063] The copper alloy device provided in this application further enhances the laser absorption capability of the copper alloy device by using copper alloy powder enriched with Cr and Zr particles in the form of dispersed phases on the surface of the copper matrix. The Cr and Zr particles enriched on the surface of the copper matrix, especially distributed at the 30~500nm scale, not only helps to reduce the laser reflectivity to 40%~60%, but also allows these Cr and Zr elements to melt more effectively and be uniformly distributed in the copper matrix during the subsequent 3D printing process. After appropriate sintering temperature and time, Cr and Zr elements precipitate in the copper matrix at the nanoscale, forming a large number of Cr and CuZr precipitates. These precipitates can further improve the mechanical properties of the device at room temperature and high temperature, while also making the electrical and thermal conductivity more excellent, meeting the high-performance application requirements in aerospace, electronic information and other fields.

[0064] In the fourth typical embodiment of this application, a method for preparing a copper alloy device is provided. The method includes: pouring copper alloy powder into a 3D printer to print a 3D printed device, and aging the 3D printed device to obtain a copper alloy device. The copper alloy powder is the copper alloy powder provided in the first typical embodiment of this application or the copper alloy powder obtained according to the preparation method provided in the second typical embodiment. Preferably, the particle size of the copper alloy powder is 15~53μm.

[0065] The copper alloy powder in this application has high electrical and thermal conductivity. By using 3D printing, the copper alloy powder can be prepared into copper alloy devices with high precision and accuracy, enabling the copper alloy devices to be widely used in high-end applications in aerospace, electronic information and other fields.

[0066] In some specific embodiments, the particle size of the copper alloy powder is 15~53μm to further improve the melting efficiency of the copper alloy powder during the 3D printing process.

[0067] In some embodiments, a laser fusion process is used for melting, with a laser power of 300-500W, a scanning speed of 400-1200mm / s, a layer thickness of 0.03-0.06mm, and a scanning interval of 0.05-0.15mm. The specific process parameters of the laser fusion process further enable the powder material to absorb laser energy more efficiently and uniformly in laser powder bed melting technology, promoting full fusion between the copper matrix and Cr and Zr particles. A reasonable match between laser power and scanning speed ensures moderate heat input to each layer, avoiding material splashing due to energy overload and incomplete fusion defects due to insufficient energy. Further control over the layer thickness and scanning interval promotes good bonding between printed layers, thereby improving the density and microstructure consistency of the formed parts.

[0068] In some specific embodiments, the laser power is any value or a range between 300W, 350W, 400W, 450W, and 500W; the scanning speed is any value or a range between 400mm / s, 500mm / s, 600mm / s, 700mm / s, 800mm / s, 900mm / s, 1000mm / s, 1100mm / s, and 1200mm / s; and the processing layer thickness is 0. The scanning distance can be any value or a range between any two of the following: 0.03mm, 0.035mm, 0.04mm, 0.045mm, 0.05mm, 0.055mm, 0.06mm; the scanning interval can be any value or a range between any two of the following: 0.05mm, 0.06mm, 0.07mm, 0.08mm, 0.09mm, 0.1mm, 0.11mm, 0.12mm, 0.13mm, 0.14mm, 0.15mm.

[0069] In some embodiments, the aging treatment temperature is 450~600℃, preferably 500~600℃, the aging treatment time is 30~360min, and the heating rate of the aging treatment is 5~15℃ / min. By adjusting the parameters of the aging treatment, the precipitation of a large number of Cr particles and CuZr particles nano-precipitates can be further promoted, giving copper alloy devices better high-temperature electrical and thermal conductivity and mechanical properties, and making them widely used in aerospace and electronic information fields.

[0070] In some specific embodiments, the aging treatment temperature is any value of 450℃, 500℃, 550℃, 600℃ or a range between any two; the aging treatment time is any value of 30min, 60min, 90min, 120min, 150min, 180min, 210min, 240min, 270min, 300min, 330min, 360min or a range between any two; and the aging treatment heating rate is any value of 5℃ / min, 6℃ / min, 7℃ / min, 8℃ / min, 9℃ / min, 10℃ / min, 11℃ / min, 12℃ / min, 13℃ / min, 14℃ / min, 15℃ / min or a range between any two.

[0071] The beneficial effects of this application will be further illustrated below with reference to embodiments and comparative examples.

[0072] Example 1

[0073] This embodiment provides a copper alloy powder, which is prepared according to the following method:

[0074] (1) Cr powder with an average particle size of 20 μm, CuZr alloy powder with an average particle size of 30 μm, and electrolytic copper powder with an average particle size of 100 μm were weighed according to a Cu:Cr:Zr mass ratio of 97.2:2.5:0.3. The Cr powder, CuZr alloy powder, and electrolytic copper powder were placed in a ball mill jar and ball milled under nitrogen protection to obtain ball-milled alloy powder. The Zr content in the CuZr alloy powder was 40%, the ball milling speed was 300 rpm, and the ball milling time was 6 h.

[0075] (2) The ball-milled alloy powder is vacuum sintered to obtain an alloy block. The alloy block is then subjected to gas atomization treatment to obtain alloy powder. The vacuum hot pressing sintering temperature is 900℃, the vacuum sintering pressure is 50MPa, the vacuum sintering time is 2h, the gas atomization treatment pressure is 3MPa, and the gas atomization treatment temperature is 1200℃.

[0076] (3) The alloy powder is placed in a tube furnace and heat-treated in a mixed atmosphere of hydrogen and nitrogen to obtain a copper alloy. The volume ratio of nitrogen to hydrogen is 500:50, the heat treatment temperature is 600℃, and the heat treatment time is 60min.

[0077] Example 2

[0078] The difference between this embodiment and Example 1 is that the average size of the Cr powder is adjusted to 30 μm, the average size of the CuZr alloy powder is adjusted to 80 μm, the average particle size of the copper powder is adjusted to 150 μm, and the mass content of Zr in the CuZr alloy powder is 20%.

[0079] Example 3

[0080] The difference between this embodiment and embodiment 1 is that in step (1), Cr powder, CuZr alloy powder and electrolytic copper powder are weighed according to the mass ratio of Cu:Cr:Zr of 95.9:4:0.1.

[0081] Example 4

[0082] The difference between this embodiment and embodiment 1 is that in step (1), Cr powder, CuZr alloy powder and electrolytic copper powder are weighed according to the mass ratio of Cu:Cr:Zr of 98.1:1.5:0.4.

[0083] Example 5

[0084] The difference between this embodiment and embodiment 1 is that in step (3), the volume ratio of nitrogen and hydrogen is adjusted to (200:200).

[0085] Example 6

[0086] The difference between this embodiment and embodiment 1 is that in step (3), the volume ratio of nitrogen and hydrogen is adjusted to (2000:20).

[0087] Example 7

[0088] The difference between this embodiment and embodiment 1 is that in step (3), the protective gas is adjusted to argon.

[0089] Example 8

[0090] The difference between this embodiment and embodiment 1 is that in step (1), the average size of the Cr powder is adjusted to 3 μm, the average size of the CuZr alloy powder is 3 μm, the average particle size of the electrolytic copper powder is 15 μm, and the mass content of Zr in the CuZr alloy powder is 5%.

[0091] Example 9

[0092] The difference between this embodiment and embodiment 1 is that in step (1), the average size of the Cr powder is adjusted to 50 μm, the average size of the CuZr alloy powder is 80 μm, the average particle size of the electrolytic copper powder is 300 μm, and the mass content of Zr in the CuZr alloy powder is 50%.

[0093] Example 10

[0094] The difference between this embodiment and embodiment 1 is that in step (1), Cr powder and electrolytic copper powder are weighed according to the mass ratio of Cu:Cr of 96:4.

[0095] Example 11

[0096] The difference between this embodiment and embodiment 1 is that in step (1), Cr powder and electrolytic copper powder are weighed according to the mass ratio of Cu:Cr of 98.5:1.5.

[0097] Example 12

[0098] The difference between this embodiment and embodiment 1 is that in step (3), the heat treatment temperature is adjusted to 550°C and the vacuum sintering time is 30 min.

[0099] Example 13

[0100] The difference between this embodiment and embodiment 1 is that in step (3), the heat treatment temperature is adjusted to 750°C and the vacuum sintering time is 120 min.

[0101] Example 14

[0102] The only difference between this embodiment and embodiment 1 is that in step (3), the heat treatment temperature is adjusted to 800°C and the vacuum sintering time is 20 min.

[0103] Comparative Example 1

[0104] The only difference between this embodiment and embodiment 1 is that in step (1), the mass ratio of Cu:Cr:Zr is 99:0.9:0.1.

[0105] Comparative Example 2

[0106] This comparative example is compared with Example 1. In step (3), no heat treatment is performed.

[0107] Comparative Example 3

[0108] The only difference between this embodiment and embodiment 1 is that in step (1), electrolytic copper powder and Cr powder are weighed according to a Cu:Cr mass ratio of 94:6.

[0109] Comparative Example 4

[0110] The only difference between this embodiment and embodiment 1 is that in step (1), electrolytic copper powder, Cr powder and CuZr alloy powder are weighed in a mass ratio of 94.4:5:0.6.

[0111] Experimental Example 1

[0112] The copper alloy powders prepared in Examples 1-14 and Comparative Examples 1-4 were subjected to performance tests, and the test methods are as follows:

[0113] (1) Powder laser reflection: At room temperature, the laser reflection of copper alloy powder at a wavelength of around 1060 nm was measured using an ultraviolet-visible-near-infrared diffuse reflectance spectrometer. The test results are shown in Table 1.

[0114] Table 1

[0115]

[0116] Note: (1) Since Cr particles and CuZr particles cannot be distinguished under a scanning electron microscope, the particle size of Cr particles and CuZr particles in Table 1 are measured simultaneously.

[0117] (2) In Comparative Example 1 and Comparative Example 2, “\” refers to the fact that the Cr particles and CuZr particles are too small to measure the average size.

[0118] Figure 1 The image shown is a SEM image of the copper alloy powder prepared in Example 1. Figure 1 It can be seen that the copper alloy powder has good sphericity.

[0119] Figure 2 The image shown is a SEM image of the copper alloy powder prepared in Example 5. Figure 2 It can be seen that the copper alloy powder has a high sphericity, and Cr particles and CuZr particles are evenly distributed on the surface of the copper matrix.

[0120] As can be seen from Examples 1-14 and Comparative Examples 1-4, the average size of Cr particles and CuZr particles is concentrated in the range of 30-500 nm, and the laser reflectivity of copper alloy powder in the near-infrared band is 40-65%.

[0121] As can be seen from the comparison between Example 1 and Examples 12-14, the copper alloy powder prepared by Example 12 with a lower heat treatment temperature has a smaller average size of Cr particles and CuZr particles, but this does not affect the subsequent preparation of copper alloy devices. However, if the heat treatment temperature is too high or the heat treatment time is too long, the average size of Cr particles and CuZr particles will be larger, and the copper alloy powder will have a lower laser reflectivity in the near-infrared light band.

[0122] As can be seen from Examples 1-14 and Comparative Example 1, the Cu content in the copper alloy powder is too high, and the Cr and Zr contents are too low. The Cr particles and CuZr particles are too small, and the average size cannot be measured. Furthermore, the copper alloy powder has a high laser reflectivity in the near-infrared light band.

[0123] As can be seen from the comparison between Examples 1-14 and Comparative Example 2, although no heat treatment is performed in step (3), the laser absorption is improved compared to the traditional composition. However, Cr particles and CuZr particles are not precipitated or the number of precipitates is small, resulting in limited improvement in laser absorption of Cr and CuZr. The copper alloy powder has a high laser reflectivity in the near-infrared light band. At the same time, this also shows that the composition and the precipitated phase play a synergistic role in the laser absorption of copper powder, and the influence of the composition is better than that of the precipitated phase.

[0124] As can be seen from Examples 1-14 and Comparative Examples 3-4, when the copper alloy powder does not contain Zr or the copper content is too high, the improvement on the average size of Cr particles and CuZr particles is not significant. Furthermore, the laser reflectivity of the copper alloy powder in the near-infrared band is not significantly different. Considering both material cost and process efficiency, the composition ratio of this application is: Cr 1.5~4.0 wt.%, Zr 0~0.4 wt.%, with the balance being Cu and unavoidable impurities.

[0125] Example 15

[0126] This embodiment provides a copper alloy device, which is prepared according to the following steps:

[0127] The copper alloy powder provided in Example 1 was added to a laser melting 3D printer. Argon gas was used for purging to control the oxygen content in the printing chamber to below 2000 ppm. The laser power of the laser melting 3D printer was set to 400 W, the scanning speed to 600 mm / s, the processing thickness to 0.03 mm, and the scanning interval to 0.1 mm. Copper alloy powder was melted layer by layer on a pure copper substrate to obtain a 3D printed device. The 3D printed device was placed in a tube furnace, and a mixture of hydrogen and argon was introduced for aging treatment to obtain a copper alloy device. The volume ratio of hydrogen to argon was 50:200, the aging treatment temperature was 550°C, the aging treatment time was 60 min, and the aging treatment heating rate was 10°C / min.

[0128] Examples 16-28

[0129] In Application Examples 16-28, the copper alloy powder prepared in Examples 2-14 was used to replace the copper alloy powder provided in Example 1 as raw material to print copper alloy devices, and the printing conditions were the same as in Example 15.

[0130] Example 29

[0131] The difference between this embodiment and embodiment 15 is that the laser power is 500W, the scanning speed is 800mm / s, the scanning layer thickness is 0.4mm, and the scanning spacing is 120μm.

[0132] Example 30

[0133] The difference between this embodiment and embodiment 15 is that the aging treatment temperature is 450℃, the aging time is 60min, and the heating rate of the aging treatment is 10℃ / min.

[0134] Example 31

[0135] The difference between this embodiment and embodiment 15 is that the aging treatment temperature is 500℃, the aging time is 360min, and the heating rate of the aging treatment is 10℃ / min.

[0136] Example 32

[0137] The difference between this embodiment and embodiment 15 is that the aging treatment temperature is 600℃, the aging time is 60min, and the heating rate of the aging treatment is 10℃ / min.

[0138] Comparative Examples 5-8

[0139] Comparative Examples 5-8 were printed into copper alloy devices using the copper alloy powders prepared in Comparative Examples 1-4 as raw materials, with the printing conditions being the same as in Example 15.

[0140] Experimental Example 2

[0141] The copper alloy devices prepared in Examples 15-32 and Comparative Examples 5-8 were subjected to performance tests, and the test methods are as follows:

[0142] (1) Density of copper alloy devices: The density of the sample was determined by the Archimedes method, and the density was calculated by multiplying the ratio of the sample density to the theoretical density by 100%.

[0143] (2) Conductivity of copper alloy devices: The conductivity of the samples was tested using an eddy current conductivity meter. The machine was calibrated using internationally annealed copper before testing. To ensure reproducibility and obtain reliable results, the probe was placed at the center of each sample and tested 5 times, and the average value was taken.

[0144] (3) Mechanical properties of copper components: The tensile strength and elongation of the samples were measured using a universal testing machine.

[0145] The test results are shown in Table 2.

[0146] Table 2

[0147]

[0148] Figure 3 This is a scanning electron microscope (SEM) image of the weld seam of the copper alloy device prepared in Example 15. Figure 3 It can be seen that the printed copper alloy device has smooth weld seams, no unmelted copper powder, and good forming ability.

[0149] Figure 4 This is a cross-sectional optical microscope image of the copper alloy device prepared in Example 16, from... Figure 4 It can be seen that the cross-sectional structure of the printed copper alloy device is free of unmelted copper powder and metallurgical pores, and the copper alloy device has high density.

[0150] Figure 5 This is a cross-sectional microstructure diagram of the copper alloy device prepared in Example 17. Figure 5 It can be seen that there are high-density nanoparticles in the microstructure of laser melting forming, resulting in excellent mechanical properties of copper alloy devices.

[0151] As can be seen from the comparison between Examples 15-32 and Comparative Examples 5-8, the copper alloy devices prepared in Examples 15-32 have a density of over 99.8%, and exhibit excellent conductivity, tensile strength, and elongation, showing broad application prospects in aerospace, electronic information, and other fields.

[0152] As can be seen from the comparison between Examples 15-25 and Examples 26-28, the Cr and CuZr particles in the copper alloy powder used to prepare copper alloy devices in Examples 27 and 28 are larger in size, resulting in lower elongation. Although excessively high heat treatment temperature or excessively long heat treatment time helps alloy elements precipitate and further improves the laser absorption rate of the powder, it may cause the powder to sinter, which is not conducive to the powder spreading and melting in the subsequent printing process.

[0153] As can be seen from the comparison between Examples 15 and Examples 30-32, by adjusting the aging treatment parameters of the printing device, the size, quantity and interface relationship of the precipitated phase in the copper matrix can be controlled, and the copper alloy device can also achieve different electrical and mechanical properties matching.

[0154] As can be seen from the comparison between Examples 15-32 and Comparative Example 5, when the aging treatment temperature and time are controlled, the copper alloy devices prepared in Examples 15-32 have better density, conductivity, tensile strength and elongation, and can achieve different mechanical property matching.

[0155] As can be seen from the comparison between Examples 15-32 and Comparative Example 6, the copper alloy devices prepared in Examples 15-32 have better density, conductivity, tensile strength and elongation, and can achieve different mechanical property matching. In Comparative Example 6, the copper alloy powder was not heat-treated, resulting in a lower elongation of the subsequent copper alloy devices.

[0156] As can be seen from the comparison of Examples 15, 24 and 25, when the Cr content is 1.5~4.0wt% and the Zr content is 0~0.4wt%, the copper alloy devices have high density and conductivity. The mechanical properties depend on the added alloy content. This shows that by controlling the element content, different strengths and conductivity can be combined to meet different industrial needs.

[0157] As can be seen from Examples 15-32 and Comparative Examples 7-8, when the Cr content exceeds 4.0 wt% or the Zr content exceeds 0.4 wt%, the laser reflectivity of the powder can continue to decrease and the tensile strength can also be improved to a certain extent, but the performance improvement is limited and the cost is relatively high.

[0158] As can be seen from the above description, the embodiments of this application achieve the following technical effects:

[0159] This application selects specific copper alloy components to control Cr and CuZr to accumulate in the form of particles on the surface of a copper matrix, and controls the average particle size to be 30~500 nm. This results in a significant reduction in the reflectivity of the copper alloy powder to infrared lasers, which is lower than that of traditional CuCrZr alloy powder. During the printing process, it can form a stable and continuous molten pool, improving the density of the printed parts to over 99.8%. Furthermore, the Cr and CuZr particles precipitate in the copper matrix, expanding its application potential under high-temperature conditions.

[0160] The copper alloy device provided in this application uses the aforementioned copper alloy powder as raw material and has low laser reflection, excellent high-temperature electrical and thermal conductivity, and mechanical properties, and has broad application prospects in aerospace, electronic information and other fields.

[0161] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A copper alloy powder, characterized in that, The copper alloy powder comprises the following components by mass fraction: Cr 1.5~4.0%, Zr 0~0.4%, with the balance being Cu and unavoidable impurities; the copper alloy powder includes a copper matrix, and Cr particles and optional CuZr particles enriched on the surface of the copper matrix, wherein the average size of the Cr particles and the CuZr particles is 30~500 nm, respectively.

2. The copper alloy powder according to claim 1, characterized in that, The copper alloy powder has a laser reflectivity of 40-65% in the near-infrared light band.

3. A method for preparing the copper alloy powder according to claim 1 or 2, characterized in that, The preparation method includes: Step S1: Weigh the raw materials according to the mass fraction of the components of the copper alloy powder, mix them, and then perform sintering and gas atomization treatment in sequence to obtain the raw material alloy powder. Step S2: The raw material alloy powder is heat-treated to obtain the copper alloy powder.

4. The preparation method according to claim 3, characterized in that, The preparation method includes: Cr powder and CuZr alloy powder are mixed and ball-milled to obtain ball-milled alloy powder. The ball-milled alloy powder is mixed with copper powder and vacuum sintered to obtain alloy rod blank. The alloy rod blank is then subjected to gas atomization treatment to obtain the raw material alloy powder. The copper powder is spherical copper powder or electrolytic copper powder, the purity of the copper powder is ≥99.9%, and the average particle size of the copper powder is 15~300μm.

5. The preparation method according to claim 4, characterized in that, The purity of the Cr powder is ≥99%, and the average particle size of the Cr powder is 3~50μm; And / or, in the CuZr alloy powder, the Zr mass content is 5%~50%, the impurity mass content is ≤1%, and the average particle size of the CuZr alloy powder is 3~80μm.

6. The preparation method according to claim 3, characterized in that, The heat treatment is carried out in a mixed atmosphere of protective gas and reducing gas; And / or, the protective gas includes at least one of nitrogen, argon or helium; And / or, the reducing gas is at least one of hydrogen and carbon monoxide; And / or, in the mixture of the protective gas and the reducing gas, the volume ratio of the protective gas to the reducing gas is (200~2000):(20~200).

7. The preparation method according to claim 3, characterized in that, The heat treatment temperature is 550–750°C, and the heat treatment time is 30–120 min.

8. A copper alloy device, characterized in that, The raw material for the copper alloy device is the copper alloy powder as described in claim 1 or 2, or the copper alloy powder obtained by the preparation method according to any one of claims 3 to 7.

9. A method for preparing a copper alloy device according to claim 8, characterized in that, The preparation method includes: pouring copper alloy powder into a 3D printer to print a 3D printed device, and aging the 3D printed device to obtain the copper alloy device; wherein the copper alloy powder is the copper alloy powder according to claim 1 or 2 or the copper alloy powder obtained by the preparation method according to any one of claims 3 to 7, and preferably the particle size of the copper alloy powder is 15~53μm.

10. The preparation method according to claim 9, characterized in that, The printing is performed using a laser powder bed melting process, wherein the laser power is 300~500W, the scanning speed is 400~1200mm / s, the processing layer thickness is 0.03~0.06mm, and the scanning spacing is 0.05~0.15mm; And / or, the aging treatment temperature is 450~600℃, preferably 500~600℃; And / or, the aging process takes 30 to 360 minutes.

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