Method for in-situ preparing spherical Cr2Nb / Cu composite powder

Abstract

The present invention discloses a method for in-situ preparing spherical Cr2Nb / Cu composite powder, which specifically includes the following steps: Step 1, preparing a CuNb master alloy; Step 2, preparing a CuCr master alloy; Step 3, using the products obtained in Step 1 and Step 2 to prepare Cr2Nb / Cu composite powder by induction melting gas atomization. The purpose of the present invention is to provide a method for in-situ preparing spherical Cr2Nb / Cu composite powder. This method uses self-made CuNb and CuCr as master alloys. By controlling the melting temperature and atomization process parameters, elements Cr and Nb fully react to form an intermetallic compound Cr2Nb with a high melting point and good thermal stability. The Cr2Nb particles in the present invention are fine and uniform, and are dispersedly distributed. The Cr2Nb / Cu powder can provide excellent raw materials for additive manufacturing and powder metallurgy, and is expected to be applied in a recyclable rocket engine combustion chamber in the future.

Description

Technical Field

[0001] The present invention belongs to the technical fields of a combustion chamber of a launch vehicle engine and high heat flux materials, and relates to a method for in-situ preparing spherical Cr2Nb / Cu composite powder. Background Art

[0002] High heat flux structural and functional materials are required for the inner wall of a launch vehicle engine combustion chamber. In addition to strength and thermal conductivity, high requirements are also placed on thermal stability. The operating temperature of the inner wall of the rocket engine, usually referred to as the "hot wall" temperature, ranges from 400°C to 700°C. With the development of reusable solid rocket booster technology, the inner wall material of the engine needs to be recycled and undergo limited maintenance and readjustment to reduce costs, which poses new challenges to the material design. At present, the combustion chambers of launch vehicle engines in China mainly use Cu-Zr and Cu-Ag-Zr alloys, which are aged to precipitate nano-sized Cu5Zr and Ag to strengthen the matrix. However, for recyclable engines, there are two major problems that are difficult to solve. The first is that when the service temperature reaches above 500°C, the precipitated phases Cu5Zr and Ag grow, resulting in softening behavior of the material. The second is that the low-cycle fatigue performance of the material is poor, and it is difficult to achieve recyclable use. Therefore, there is an urgent need for high-strength, high-conductivity, high-temperature-resistant copper-based materials with excellent fatigue performance to fill the existing industrial gap in China.

[0003] The Cr2Nb / Cu composite material has been widely studied by scholars due to its excellent high-temperature performance and low-cycle fatigue performance. Elements Cr and Nb are prone to forming intermetallic compound Cr2Nb with a high melting point and good thermal stability, which remains stable before 1733°C. At a service temperature of 400 - 700°C, Cr2Nb particles will hinder grain boundary sliding and pin grain growth, thus ensuring the overall high-temperature mechanical properties of the material. Patent: A method for preparing a high-temperature-resistant and high-conductive Cu-Cr-Nb-based copper alloy powder (application number: 202111279275.X) uses a plasma rotating electrode to prepare Cu-Cr-Nb alloy powder. The only drawback is that the distribution of the reinforcing phase Cr2Nb particles in the powder is relatively uneven, which will affect the uniformity of the material after subsequent powder metallurgy and 3D printing. Chinese patent: A method for preparing a high-temperature-resistant Cu-Cr-Nb-Ce alloy for the inner lining of an aeroengine combustion chamber (authorization announcement number CN 110218897 B) prepares a Cu-Cr-Nb-Ce alloy. According to the accompanying drawings, the size of Cr2Nb particles in the matrix reaches the micron level, which will greatly reduce the mechanical properties of the material. Therefore, how to make the reinforcing phase Cr2Nb particles in Cr2Nb / Cu fine, uniform, and dispersed is the main problem at present. Summary of the Invention

[0004] The object of the present invention is to provide a method for in-situ preparing spherical Cr2Nb / Cu composite powder. This method uses self-made CuNb and CuCr as master alloys, and by controlling the melting temperature and atomization process parameters, elements Cr and Nb fully react to form an intermetallic compound Cr2Nb with high melting point and good thermal stability. The Cr2Nb particles in the present invention are fine, uniform and dispersedly distributed.

[0005] The technical solution adopted by the present invention is a method for in-situ preparing spherical Cr2Nb / Cu composite powder, which specifically includes the following steps:

[0006] Step 1, prepare CuNb master alloy;

[0007] Step 2, prepare CuCr master alloy;

[0008] Step 3, use induction melting gas atomization to prepare Cr2Nb / Cu composite powder from the products obtained in Step 1 and Step 2.

[0009] The characteristics of the present invention also lie in:

[0010] The specific process of Step 1 is as follows:

[0011] Step 1.1, select pure Cu powder and pure Nb powder as raw materials, and under vacuum, respectively perform heat preservation treatment on pure Cu powder and pure Nb powder at 80°C - 100°C for 5h - 10h;

[0012] Step 1.2, perform pre-mixing treatment on the pure Cu powder and pure Nb powder treated in Step 1.1 on a V-type mixer at 50HZ - 70HZ for 5h - 10h to obtain a CuNb mixed powder. In this CuNb mixed powder, the content of Nb is 1.5 - 15wt.%, and the rest is Cu. The mass fractions of Nb and Cu add up to 100%;

[0013] Step 1.3, ball mill the CuNb mixed powder obtained in Step 1.2 in a ball mill, add a grinding aid during ball milling, and obtain a CuNb alloy after ball milling;

[0014] Step 1.4, use a cold isostatic press to perform cold isostatic pressing on the CuNb alloy powder after ball milling in Step 1.3, and the pressure is 200MPa - 250MPa;

[0015] Step 1.5, perform machining on the CuNb alloy after cold isostatic pressing in Step 1.4;

[0016] Step 1.6, perform vacuum consumable arc melting on the CuNb alloy treated in Step 1.5, the melting current is 40A - 70A, and repeatedly melt 3 - 6 times;

[0017] Step 1.7: The CuNb alloy processed in Step 1.6 is machined to remove the skin and cut into pieces for standby.

[0018] In Step 1.3, during ball milling, the rotation speed of the ball mill is 700 / rpm - 1400 / rpm, the ball milling time is 5h - 10h, and the dosage of the grinding aid is 1wt.% - 3wt.% relative to the CuNb mixed powder.

[0019] The specific process of Step 2 is as follows: Using pure Cu and pure Cr particles as raw materials to obtain a CuCr mixture; in this CuCr mixture, the content of Cr is 1.5wt.% - 15wt.%, and the rest is Cu, and the mass fractions of Nb and Cu add up to 100%; the CuCr mixture is melted in a vacuum induction furnace at a melting temperature of 1500°C - 1700°C for 10 - 30 minutes, and melted repeatedly 3 times to obtain a CuCr alloy, which is then machined to remove the skin and cut for standby.

[0020] The specific process of Step 3 is as follows:

[0021] The CuCr and CuNb alloys prepared in Step 1 and Step 2 are placed in the melting crucible of the atomization chamber, and the melting temperature is raised to 1500°C - 1700°C, and the holding time is 10min - 30min to obtain a composite suspension, and the composite suspension is atomized to obtain a Cr2Nb / Cu composite powder with a dispersed distribution.

[0022] In Step 3, the atomization pressure is 3.5MPa - 7.5MPa, and the aperture of the diversion tube of the atomizer in the atomization chamber is 2.5mm - 4.5mm.

[0023] The beneficial effects of the present invention are as follows:

[0024] 1. Compared with the current traditional Cu - Ag - Zr alloy that needs to be strengthened by aging treatment, the Cr2Nb / Cu composite powder of the present invention is formed by 3D printing or powder metallurgy. The Cr2Nb particles are all dispersed in the Cu matrix and do not need subsequent aging treatment, and can directly undergo subsequent processing and use, realizing short - process controllable preparation.

[0025] 2. The strengthening phase Cr2Nb does not soften in the service temperature range (400°C - 700°C), providing a prerequisite for multiple recyclable uses.

[0026] 3. Compared with the Cu-Cr-Nb alloy prepared in the prior art, the Cr2Nb particles in the Cr2Nb / Cu material powder prepared by the present invention are dispersed in size and have a small size, which will greatly improve the comprehensive performance of the material. The Cr2Nb / Cu powder can provide excellent raw materials for additive manufacturing and powder metallurgy, and is expected to be applied in the combustor of a recyclable rocket engine in the future. Description of the Drawings

[0027] Figure 1 It is the surface morphology diagram of the Cr2Nb / Cu composite powder prepared in Example 3 of the method for in-situ preparing spherical Cr2Nb / Cu composite powder of the present invention;

[0028] Figure 2 It is the cross-sectional structure of the Cr2Nb / Cu composite powder prepared in Example 3 of the method for in-situ preparing spherical Cr2Nb / Cu composite powder of the present invention;

[0029] Figure 3 It is the high-magnification spherical aberration microstructure diagram of the Cr2Nb / Cu composite powder prepared in Example 3 of the method for in-situ preparing spherical Cr2Nb / Cu composite powder of the present invention. Detailed Description of the Invention

[0030] The present invention will be described in detail below with reference to the drawings and specific embodiments.

[0031] The method for in-situ preparing spherical Cr2Nb / Cu composite powder of the present invention specifically includes the following steps:

[0032] Step 1, preparing a CuNb master alloy, and the specific process is as follows:

[0033] Step 1.1, first select pure Cu powder and pure Nb powder as raw materials, and under vacuum, perform heat treatment on the pure Cu powder and pure Nb powder at 80°C - 100°C for 5h - 10h respectively;

[0034] Step 1.2, perform pre-mixing treatment on the pure Cu powder and pure Nb powder treated in Step 1.1 on a V-type mixer at 50HZ - 70HZ for 5h - 10h to obtain a CuNb mixed powder. In this CuNb mixed powder, the content of Nb is 1.5 - 15wt.%, and the rest is Cu, and the mass fractions of Nb and Cu add up to 100%.

[0035] Step 1.3: The CuNb mixed powder obtained in Step 1.2 is subjected to high-energy ball milling in a ball mill with a grinding aid added during ball milling to obtain a CuNb alloy. During ball milling: the rotation speed is 700 / rpm - 1400 / rpm, and the ball milling time is 5h - 10h. The grinding aid used is 1% - 3% (wt.%) (this dosage is relative to the amount of the mixed powder obtained in Step 1.2), and the grinding aid is stearic acid. Argon is filled during ball milling for protection to prevent oxidation of the alloy powder during high-energy ball milling. The rotation speed of the stirring shaft during ball milling adopts an alternating rotation speed. The continuous intense collision, shearing, friction and other forces between the grinding balls and the powder particles are conducive to the refinement of the powder and the realization of alloying.

[0036] Step 1.4: The CuNb alloy powder after ball milling in Step 1.3 is subjected to isostatic cold pressing using a cold isostatic press, and the pressure is 200MPa - 250MPa;

[0037] Step 1.5: The CuNb alloy after cold isostatic pressing in Step 1.4 is machined, such as turning threads, to facilitate clamping during later processing;

[0038] Step 1.6: The CuNb alloy treated in Step 1.5 is subjected to vacuum consumable arc melting, and the melting current is 40A - 70A, and it is repeatedly melted 3 times - 6 times (ensuring that the Nb particles in the CuNb alloy are fine and can be evenly distributed in the matrix).

[0039] Step 1.7: The CuNb alloy treated in Step 1.6 is machined to remove the skin and cut into small pieces for standby.

[0040] Step 2: Prepare a CuCr master alloy, and the specific steps are as follows:

[0041] Pure Cu and pure Cr particles are used as raw materials to obtain a CuCr mixture; in this CuCr mixture, the content of Cr is 1.5wt.% - 15wt.%, and the rest is Cu. The mass fractions of Nb and Cu add up to 100%; the CuCr mixture is melted in a vacuum induction furnace at a melting temperature of 1500°C - 1700°C for 10 - 30 minutes, and it is repeatedly melted 3 times (ensuring that the Cr particles in the CuCr alloy are fine and can be evenly distributed in the copper matrix) to obtain a CuCr alloy, and then it is machined to remove the skin and cut for standby.

[0042] Step 3: Prepare Cr2Nb / Cu composite powder by induction melting gas atomization, and the specific process is as follows:

[0043] Place the CuCr and CuNb alloys prepared in Step 1 and Step 2 into the melting crucible in the atomization chamber. Raise the melting temperature to 1500°C - 1700°C and keep it warm for 10 min - 30 min (the viscosity of the composite suspension decreases) to obtain a composite suspension. Start atomizing the composite suspension with an atomization pressure of 3.5 MPa - 7.5 MPa. The aperture of the diversion tube of the atomizer in the atomization chamber is between 2.5 mm and 4.5 mm to obtain a Cr2Nb / Cu composite powder with a dispersed distribution.

[0044] The Cr2Nb / Cu composite powder of the present invention can replace Cu-Zr, Cu-Ag-Zr alloys, etc. currently used in the combustors of recyclable engines of launch vehicles and high heat flux devices.

[0045] The present invention uses self-made CuNb and CuCr master alloys. By controlling the melting parameters and atomization process, Cr and Nb elements are all formed into Cr2Nb particles in the Cu liquid, so subsequent aging treatment is not required. And the in-situ formed Cr2Nb particles are more dispersed in the matrix than the externally added Cr2Nb particles. Therefore, in the subsequent powder forming stage, the uniformity of the material can be guaranteed.

[0046] The present invention independently develops in-situ preparation of high-strength, high-conductivity and high-temperature-resistant Cr2Nb / Cu composite material powder, which does not require aging treatment. After hot pressing and 3D printing the formed parts, they can be directly used after processing. The Cr2Nb particles in the powder are evenly distributed and have excellent high-temperature resistance, and can replace most of the current Cu alloy materials used for high heat flux.

[0047] Example 1

[0048] Step 1: First, select pure Cu powder and pure Nb powder as raw materials, and under vacuum, treat the powder at 80°C for 5 hours.

[0049] Step 2: Mix the Cu powder and Nb powder, and perform a pre-mixing treatment on the CuNb powder at 50 HZ for 5 hours on a V-type mixer. In the CuNb powder, the content of Nb is 1.5 wt.%, and the content of Cu is 98.5 wt.%.

[0050] Step 3: Then, perform high-energy ball milling on the mixed powder in a ball mill, adding a grinding aid during ball milling to obtain a CuNb alloy after ball milling. During ball milling: the rotation speed is 700 / rpm, and the ball milling time is 5 hours. The grinding aid used is 1% (wt.%) stearic acid, and an inert gas is filled during ball milling to prevent oxidation of the alloy powder during high-energy ball milling. The rotation speed of the stirring shaft during ball milling adopts an alternating rotation speed, and the continuous intense collision, shearing, friction and other forces between the grinding balls and the powder particles are conducive to the refinement of the powder and the realization of alloying.

[0051] Step 4: Use a cold isostatic press to perform cold isostatic pressing on the ball-milled CuNb alloy powder at a pressure of 200 MPa.

[0052] Step 5: Machine the cold isostatically pressed CuNb alloy to turn threads (for easy clamping in the next step).

[0053] Step 6: Perform vacuum consumable arc melting on the CuNb alloy at a melting current of 40 A and repeat the melting 3 times.

[0054] Step 7: Machine, remove the skin, and cut the CuNb alloy from Step 6 for standby.

[0055] Step 8: Use pure Cu and pure Cr particles as raw materials, mix them to obtain a CuCr mixture, where the content of Cr is 1.5 wt.%, and the content of Cu is 98.5 wt.%. Place the CuCr mixture in a vacuum induction furnace for melting at a melting temperature of 1500 °C and repeat the melting 3 times. Ensure that the Cr particles in the CuCr alloy are fine and evenly distributed in the copper matrix, and then machine, remove the skin, and cut it for standby.

[0056] Step 9: Place the prepared CuCr and CuNb alloys in the melting crucible of the atomization chamber, raise the melting temperature to 1300 °C, hold for 10 min to obtain a composite suspension, start atomizing the composite suspension at an atomization pressure of 3.5 MPa, with the aperture of the diversion tube being 2.5 mm, to obtain Cr2Nb / Cu composite powder with a dispersed distribution.

[0057] Example 2

[0058] Step 1: First, select pure Cu powder and pure Nb powder as raw materials and treat the powders under vacuum at 90 °C for 6 hours.

[0059] Step 2: Mix the Cu powder and Nb powder and perform pre-mixing on the CuNb powder for 6 hours at 60 HZ on a V-type mixer. In the CuNb powder, the content of Nb is 15 wt.%, and the content of Cu is 85 wt.%.

[0060] Step 3: Perform high-energy ball milling on the mixed powder in a ball mill, adding a grinding aid during ball milling to obtain a CuNb alloy after ball milling. During ball milling: the rotation speed is 900 / rpm, and the ball milling time is 10 hours. The grinding aid used is 2% (wt.%) stearic acid, and an inert gas is filled during ball milling for protection to prevent oxidation of the alloy powder during high-energy ball milling. The rotation speed of the stirring shaft during ball milling adopts an alternating speed, and the continuous intense collision, shear, and friction forces between the grinding balls and the powder particles are conducive to the refinement of the powder and the realization of alloying.

[0061] Step 4: Use a cold isostatic press to perform cold isostatic pressing on the ball-milled CuNb alloy powder at a pressure of 220 MPa.

[0062] Step 5: Machine the cold isostatically pressed CuNb alloy to turn threads.

[0063] Step 6: Perform vacuum consumable arc melting on the CuNb alloy. The melting current is 55 A, and it is repeatedly melted 4 times to ensure that the Nb particles in the CuNb alloy are fine and evenly distributed in the matrix.

[0064] Step 7: Machine the CuNb alloy obtained in Step 6, such as removing the skin and cutting, and reserve it for later use.

[0065] Step 8: Use pure Cu and pure Cr particles as raw materials. After mixing, a CuCr mixture is obtained, where the content of Cr is 15 wt.% and the content of Cu is 85 wt.%. Place the CuCr mixture in a vacuum induction furnace for melting. The melting temperature is 1600 °C and it is repeatedly melted 5 times to ensure that the Cr particles in the CuCr alloy are fine and evenly distributed in the copper matrix. After that, machine it to remove the skin and cut, and reserve it for later use.

[0066] Step 9: Place the prepared CuCr and CuNb alloys in the melting crucible of the atomization chamber. Raise the melting temperature to 1600 °C, keep it warm for 20 min, and the atomization pressure is 5 MPa. The aperture of the diversion tube is between 3.5 mm. When the viscosity of the composite suspension decreases, start the atomization behavior to obtain the Cr2Nb / Cu composite powder with a dispersed distribution.

[0067] Example 3

[0068] Step 1: Select pure Cu powder and pure Nb powder as raw materials. Under vacuum, treat the powder at 100 °C for 10 hours.

[0069] Step 2: Mix the Cu powder and Nb powder, and perform pre-mixing treatment on the CuNb powder at 70 HZ for 10 hours on a V-type mixer. In the CuNb powder, the content of Nb is 10 wt.% and the content of Cu is 90 wt.%.

[0070] Step 3: Then perform high-energy ball milling on the mixed powder in a ball mill, adding a grinding aid during ball milling to obtain a CuNb alloy after ball milling. During ball milling: the rotation speed is 1400 / rpm, and the ball milling time is 30 hours. The grinding aid used is 3% (wt.%) stearic acid. During the ball milling process, an inert gas is filled for protection to prevent oxidation of the alloy powder during high-energy ball milling. The rotation speed of the stirring shaft during ball milling adopts an alternating speed. The continuous intense collision, shear, and friction forces between the grinding balls and the powder particles are conducive to the refinement of the powder and the realization of alloying.

[0071] Step 4: Use a cold isostatic press to perform isostatic pressing on the ball-milled CuNb alloy powder at a pressure of 250 MPa.

[0072] Step 5: Machine the cold isostatically pressed CuNb alloy to cut threads.

[0073] Step 6: Perform vacuum consumable arc melting on the CuNb alloy. The melting current is 70 A, and it is repeatedly melted 6 times to ensure that the Nb particles in the CuNb alloy are fine and evenly distributed in the matrix.

[0074] Step 7: Machine, debark, and cut the CuNb alloy obtained in Step 6 for standby.

[0075] Step 8: Use pure Cu and pure Cr particles as raw materials. After mixing, a CuCr mixture is obtained, where the content of Cr is 10 wt.%, and the content of Cu is 90 wt.%. Place the CuCr mixture in a vacuum induction furnace for melting. The melting temperature is 1700 °C, and it is repeatedly melted 3 times. Ensure that the Cr particles in the CuCr alloy are fine and evenly distributed in the copper matrix. Then, machine, debark, and cut it for standby.

[0076] Step 9: Place the prepared CuCr and CuNb alloys in the melting crucible of the atomization chamber. Raise the melting temperature to 1700 °C, keep it warm for 30 min, and the atomization pressure is 7.5 MPa. The aperture of the diversion tube is between 4.5 mm. When the viscosity of the composite suspension decreases, start the atomization behavior to obtain Cr2Nb / Cu composite powder with a dispersed distribution.

[0077] Figure 1 is the surface morphology diagram of the Cr2Nb / Cu composite powder prepared in Example 3. From Figure 1 it can be seen that the powder has good sphericity, and fine white Cr2Nb particles are dispersed on the powder surface.

[0078] Figure 2 is the cross-sectional microstructure diagram of the Cr2Nb / Cu composite powder prepared in Example 3. From Figure 2 it can be more intuitively seen the Cr2Nb particles in the composite powder.

[0079] Figure 3 is the high-magnification spherical aberration microstructure diagram of the Cr2Nb / Cu composite powder prepared in Example 3. From Figure 3 it can be seen that a large number of dispersed secondary nano Cr2Nb particles are distributed in the grains, with sizes between 50 nm and 200 nm, and primary Cr2Nb particles are distributed at the grain boundaries, with sizes between 500 nm and 700 nm.

[0080] Table 1 shows the characteristic indexes of the Cr2Nb / Cu composite powder prepared in Example 3 of the present invention. It can be seen from Table 1 that the D50 of the powder is 38.31 μm, and the fluidity of the powder is 23.2 g / s, fully meeting the requirements of the 3D printing raw materials for the composite powder.

[0081] Table 1. Characteristic Indexes of Cr2Nb / Cu Composite Powder

[0082]

Claims

1. A method for in-situ preparation of spherical Cr2Nb / Cu composite powder, characterized in that: The specific steps include: Step 1, preparing a CuNb master alloy; The specific process of step 1 is as follows: Step 1.1, selecting pure Cu powder and pure Nb powder as raw materials, and subjecting the pure Cu powder and pure Nb powder to a heat preservation treatment at 80° C.-100° C. for 5 h-10 h under vacuum; Step 1.2, pre-mixing the pure Cu powder and pure Nb powder treated in step 1.1 in a V-type mixer at 50 Hz -70 Hz for 5 h -10 h to obtain a CuNb-containing mixed powder, wherein the content of Nb in the CuNb mixed powder is 1.5-15 wt.%, and the rest is Cu, and the sum of the mass fractions of Nb and Cu is 100%; Step 1.3, ball milling the CuNb mixed powder obtained in step 1.2 in a ball mill, adding a grinding aid during ball milling, and obtaining a CuNb alloy after ball milling; In the step 1.3, during ball milling, the rotation speed of the ball mill is 700 / rpm-1400 / rpm, the ball milling time is 5h-10h, and the amount of the grinding aid is 1wt.%-3wt.% relative to the CuNb mixed powder; Step 1.4, using a cold isostatic press to perform isostatic cold pressing on the CuNb alloy powder after ball milling in step 1.3 at a pressure of 200 MPa-250 MPa; Step 1.5, machining the CuNb alloy after cold isostatic pressing in step 1.4; Step 1.6, performing vacuum consumable arc melting on the CuNb alloy processed in step 1.5, with a melting current of 40A-70A, and repeatedly melting for 3-6 times; Step 1.7, machining and peeling the CuNb alloy processed in step 1.6, and cutting it into blocks for later use; Step 2, preparing CuCr master alloy; The specific process of step 2 is as follows: pure Cu and pure Cr particles are used as raw materials to obtain a CuCr mixture; in the CuCr mixture, the content of Cr is 1.5wt.%-15wt.%, and the rest is Cu, and the mass fraction of Nb and Cu adds up to 100%; the CuCr mixture is smelted in a vacuum induction furnace at a smelting temperature of 1500°C-1700°C for 10-30 minutes, and the smelting is repeated 3 times to obtain a CuCr alloy, which is then peeled and cut by machining and reserved for later use; Step 3, the products obtained in step 1 and step 2 are subjected to induction melting and gas atomization to prepare Cr2Nb / Cu composite powder; the specific process of step 3 is as follows: The CuCr and CuNb alloys prepared in step 1 and step 2 are placed in a smelting crucible in an atomization chamber, the smelting temperature is raised to 1500° C.-1700° C., and the holding time is 10 min-30 min to obtain a composite suspension, and the composite suspension is atomized to obtain a dispersed Cr2Nb / Cu composite powder; In step 3, the atomization pressure is 7.5 MPa, and the aperture of the guide tube of the atomizer in the atomization chamber is 2.5 mm-4.5 mm.

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