A method for preparing a high-strength, high-conductivity copper-chromium-niobium conductive rod

Abstract

This invention discloses a method for preparing a high-strength, high-conductivity copper-chromium-niobium conductive rod. The method involves loading CuCrNb alloy powder into a plastic sleeve mold for cold isostatic pressing, then loading the cold isostatically pressed rod into a sheathing mold for degassing and sealing, followed by hot isostatic pressing to obtain the copper-chromium-niobium alloy rod, which is then machined to obtain the copper-chromium-niobium conductive rod. This invention employs a two-stage process to directly prepare the copper-chromium-niobium alloy rod, improving material utilization and resulting in a copper-chromium-niobium conductive rod with high strength, high conductivity, high softening temperature, uniform microstructure, and low impurity content, meeting the requirements for use in vacuum interrupters.

Description

Technical Field

[0001] This invention relates to the field of copper alloy technology, specifically to a method for preparing a high-strength, high-conductivity copper-chromium-niobium conductive rod. Background Technology

[0002] The main material of the moving and stationary conductive rods in a vacuum interrupter is usually oxygen-free copper, which forms the main conductive circuit and primarily functions to conduct current. To further improve the material properties of the conductive rods, copper-chromium-niobium (CNC-Niobium) material is selected as the main material, which can significantly improve the conductivity and strength of the rods. Using a two-stage process of cold isostatic pressing and hot isostatic pressing, high-strength and high-conductivity CNC-Niobium conductive rods can be obtained, with material properties and efficiency superior to traditional conductive rod materials.

[0003] Microalloyed Cu-Cr-Nb alloys are dual-phase strengthened copper alloys with two precipitated phases: Cr and Cr2Nb. The Cr2Nb phase exhibits excellent thermal stability, thus providing the alloy with good resistance to softening. Cu-Cr-Nb alloys prepared using traditional melting methods require high-temperature solution treatment and aging to fully realize their properties. High-temperature solution treatment integrates solute atoms into the Cu matrix, while aging precipitates nano-precipitates. However, high-temperature solution treatment inevitably leads to grain growth and the formation of large Cr2Nb particles. Furthermore, Cu-Cr-Nb alloys prepared using traditional melting methods also generate large Cr2Nb particles during solidification, thus affecting the alloy's properties.

[0004] Patent CN117655326A discloses a method for near-net-shape forming of Cu-Cr-Nb combustion chamber walls using hot isostatic pressing. The invention discloses a method for near-net-shape forming of Cu-Cr-Nb combustion chamber walls using hot isostatic pressing. The process of this invention is atomization powder preparation - hot isostatic pressing - removal of cladding - milling groove. Using hot isostatic pressing for near-net-shape forming easily results in the alloy rod having "small ends and large middle", resulting in low material utilization and high cost.

[0005] Patent CN112126804A discloses a method for preparing copper-chromium-niobium alloy rods by cooling and direct aging in a copper mold. The invention discloses a method for preparing copper-chromium-niobium alloy rods by cooling and direct aging in a copper mold. The process of this invention is a vacuum induction melting process. The patented method is simple and low in cost, but the metallographic structure of the prepared copper-chromium-niobium conductive rods is coarse, and foreign inclusions are easily introduced when using a crucible as a carrier. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a method for preparing a high-strength, high-conductivity copper-chromium-niobium conductive rod.

[0007] The technical solution of the present invention is: a method for preparing a high-strength and high-conductivity copper-chromium-niobium conductive rod, which involves loading CuCrNb alloy powder into a rubber sleeve mold for cold isostatic pressing, then loading the cold isostatically pressed rod into a cladding mold for degassing and sealing, followed by hot isostatic pressing to obtain a copper-chromium-niobium alloy rod, and then machining it to obtain a copper-chromium-niobium conductive rod.

[0008] Furthermore, a method for preparing a high-strength, high-conductivity copper-chromium-niobium conductive rod includes the following steps: Step 1, Atomization Powder Preparation: CuCrNb alloy powder is prepared by plasma rotating gas atomization; Step 2: Make the sleeve mold: Make the corresponding sleeve mold according to the shape and size of the conductive rod, and set it aside for later use; Step 3, Loading: Place the CuCrNb alloy powder prepared in Step 1 into the rubber sleeve mold, using a rubber sleeve with a diameter of 85-95mm and a length of 1000-1100mm; Step 4, Cold Isostatic Pressing: Place the loaded rubber sleeve mold into the cold isostatic pressing furnace cavity for cold isostatic pressing to obtain cold isostatic pressed bars; Step 5, Degassing and Sealing: The cold isostatically pressed bar stock is loaded into the cladding mold of Step 2, then placed in a heat treatment furnace for heating, and after being taken out, it is placed in a degassing device. A vacuum pumping system is used to degas and vacuum the bar stock at high temperature, and then the pumping port is sealed. Step 6, Hot Isostatic Pressing: Place the sealed and welded cladding mold into the hot isostatic pressing furnace cavity for hot isostatic pressing sintering at a temperature of 850-1000℃, a pressure of 110-130MPa, and a time of 4-6h. Step 7: Remove the cladding mold: Use machining to remove the cladding mold to obtain copper-chromium-niobium alloy rods; Step 8: Machining the copper-chromium-niobium alloy rod according to the drawing requirements to obtain the copper-chromium-niobium conductive rod.

[0009] Explanation: Using atomized Cr2Nb master alloy and copper as raw materials, a vacuum induction melting gas atomization process is adopted to obtain Cu-Cr-Nb spherical powder. The mold is made into a sleeve and copper-chromium-niobium alloy rods are obtained through a two-step process of cold isostatic pressing and hot isostatic pressing. The cold isostatic pressing is used to form the copper-chromium-niobium alloy rods, which is mainly used for powder material forming and provides a blank for the further hot isostatic pressing process. The hot isostatic pressing process is then used to improve the density of the alloy. Traditional methods directly produce alloy rods using hot isostatic pressing (HIP), which results in significant deformation and a "small at both ends and large in the middle" phenomenon. However, by combining cold and hot isostatic pressing, the material utilization rate of copper-chromium-niobium alloys can be improved. This is a cost-effective and efficient method for manufacturing conductive rods, producing copper-chromium-niobium conductive rods with high strength, high conductivity, high softening temperature, uniform microstructure, and low impurity content.

[0010] Furthermore, the atomization powder preparation specifically involves: preparing CuCrNb alloy powder via plasma rotational atomization, assembling the prepared CuCrNb alloy electrode rod into a feeding device, melting the alloy under a high-vacuum argon atmosphere, and preparing atomized CuCrNb alloy powder by high-speed rotation.

[0011] Note: Compared with gas atomization, the plasma rotary atomization method produces alloy powders with a narrower particle size distribution and more concentrated particle size. Furthermore, since this method does not require any solvents or other additives during the production process, the resulting metal powder has high purity, fewer ceramic inclusions, higher cleanliness, higher sphericity, better flowability, less oxygen increment, lower oxygen content, lower surface activity, and better melting effect.

[0012] Furthermore, the heat treatment furnace is heated to 500~700℃.

[0013] Explanation: Processing with the above-mentioned heat treatment furnace heating parameters can optimize the material's structure and properties, eliminate gases in the material, reduce product defects, and improve product quality and reliability. After heat treatment, the internal gases and impurities have been removed to a certain extent, which provides better conditions for the subsequent degassing process, ensuring that the degassing process is more effective and further reducing defects such as bubbles and cracks in the product.

[0014] Furthermore, in the degassing equipment, a vacuum pumping system is used for high-temperature degassing for 12-15 hours until the vacuum degree inside the encapsulation mold reaches 1×10⁻⁶. -3 Pa ~ 1×10 -4 After Pa, the vent of the casing mold is sealed with argon arc welding.

[0015] Note: Before degassing, the material may contain gases such as water vapor, hydrogen, carbon dioxide, and carbon monoxide, as well as impurities. If these gases and impurities are not removed, they may cause bubbles and cracks in the product during hot isostatic pressing, affecting product quality. Furthermore, degassed materials are easier to process during hot isostatic pressing, which improves production efficiency and reduces scrap rate, thereby lowering production costs.

[0016] Furthermore, the pressure of the cold isostatic pressing is 200-280 MPa, and the holding time is 5-15 min.

[0017] Explanation: Cold isostatic pressing (COP) is an isostatic pressing process performed at room temperature. Powdered materials are placed in a sealed high-pressure container, and uniform high pressure is applied in all directions to promote compaction and molding of the powder. This process can produce high-density, highly uniform products while maintaining the original properties of the material. It is suitable for molding various materials. Isostatic pressing near-net-shape forming technology is an integrated material forming and preparation technology that combines traditional powder metallurgy technology with mold manufacturing technology. The cold isostatic pressing process using the above parameters can effectively meet the preparation requirements of this method.

[0018] Furthermore, after the temperature of the hot isostatic pressing sintering reaches 850-950℃, the temperature is periodically and uniformly controlled according to X%~100% of the maximum temperature of 1000℃, and ultrasonic external field assistance is applied during this period. The duration of each periodic uniform control is 20~40 minutes, and X% satisfies the following formula: X%={1-[(N0—N min ) / N max ]}×100% Where N0 is the actual pressure value of hot isostatic pressure; N max This refers to the maximum pressure value within the pressure range, i.e., 130 MPa; N min This is the minimum pressure value within the pressure range, i.e., 110 MPa.

[0019] Explanation: Hot isostatic pressing (HIP) is a process performed under both high temperature and high pressure. In addition to the high pressure, heating is also carried out simultaneously. HIP can further improve the density and strength of the product, and improve the mechanical properties and metallographic structure of the material. This technology can produce complex structural components with dimensions and performance requirements in a single process, eliminating the need for complex thermal processing, greatly improving material utilization, shortening delivery cycles, and effectively reducing manufacturing costs. The densification process of hot isostatic pressing generally consists of three stages: particle approach and rearrangement, plastic deformation, and diffusion creep. In actual production and experiments, we have found that the set temperature should exceed the temperature required for diffusion bonding, but it cannot be too high to prevent material deformation and overheating. At the same time, the set temperature cannot be too low, otherwise the internal creep of the material will be insufficient. By using the pressure of hot isostatic pressing as a reference parameter, setting a variable and controllable temperature range for hot isostatic pressing sintering, and adopting variable temperature hot isostatic pressing treatment, this problem can be significantly improved and the material performance can be enhanced. Furthermore, based on the aforementioned variable and controllable temperature range, the addition of ultrasonic external field assistance can significantly improve the density of materials undergoing plastic deformation. Under the assistance of ultrasonic external field and hot isostatic pressing sintering within the variable and controllable temperature range, the material properties of copper-chromium-niobium conductive rods can be significantly enhanced.

[0020] Furthermore, the power of the ultrasonic external field assistance is 110W~330W, the frequency is 20Hz, and the ultrasonic external field assistance is modulated with periodic uniform velocity control, specifically including the following steps: 1) During the period from X% to 100%, the power of the ultrasonic field assistance decreased synchronously and at an average speed from 330W to 110W; 2) During the period from 100% to X%, the power of the ultrasonic field assistance increased synchronously and at a constant rate from 110W to 330W.

[0021] Explanation: Variable ultrasonic field assistance can further improve the microstructure. Ultrasonic vibration can break up grains, refine the grain structure of copper-chromium-niobium alloys, and thus improve their mechanical properties. It can also promote element diffusion, enhance the diffusion ability of atoms, promote the uniform distribution of elements such as copper, chromium, and niobium, and improve the alloy's performance. At the same time, it can reduce residual stress. The ultrasonic field can help release residual stress inside the alloy, improving its dimensional stability and reliability. Furthermore, it can further improve density, helping to reduce the formation of porosity and defects, and increasing the alloy's density. While ensuring the increase in density of materials undergoing plastic deformation, it avoids deformation and overheating of materials during hot isostatic pressing, thereby further strengthening the hardness and conductivity of copper-chromium-niobium conductive rods.

[0022] Compared with the prior art, the beneficial effects of the present invention are: The method for preparing copper-chromium-niobium conductive rods of this invention employs a two-step process of cold isostatic pressing and hot isostatic pressing to directly prepare copper-chromium-niobium alloy rods. This method can improve the utilization rate of materials and enable the copper-chromium-niobium conductive rods to have the characteristics of high strength and high conductivity, high softening temperature, uniform metallographic structure, and low impurity content, which meets the requirements for use in vacuum interrupters. Furthermore, it avoids the phenomenon of alloy rods being "small at both ends and large in the middle," and the preparation method is simple and has low production cost. Attached Figure Description

[0023] Figure 1 This is a flowchart of the preparation method of the copper-chromium-niobium conductive rod of the present invention.

[0024] Figure 2 This is a metallographic photograph of the copper-chromium-niobium conductive rod of Embodiment 1 of the present invention. Detailed Implementation

[0025] The present invention will now be described in more detail with reference to specific embodiments, so as to better demonstrate the advantages of the present invention.

[0026] Example 1: A method for preparing a high-strength, high-conductivity copper-chromium-niobium conductive rod, such as... Figure 1 As shown, CuCrNb alloy powder is cold isostatically pressed into a rubber-sleeved mold, and then the cold isostatically pressed bar is placed into a cladding mold for degassing and sealing. Subsequently, it undergoes hot isostatic pressing to obtain a copper-chromium-niobium alloy bar, which is then machined to obtain a copper-chromium-niobium conductive rod. Raw materials: Cr2Nb master alloy, TU1 oxygen-free copper rod, wherein Cr2Nb master alloy accounts for 6wt%, and the balance is Cu, and Cu is oxygen-free copper rod; wherein, in Cr2Nb master alloy: Cr element accounts for 55% and Nb element accounts for 45%. The preparation method of copper-chromium-niobium conductive rod includes the following steps: Step 1, Atomization Powder Preparation: CuCrNb alloy powder is prepared by plasma rotation atomization method. The prepared CuCrNb alloy electrode rod is assembled into the feeding device. Under high vacuum argon atmosphere, the alloy is melted and atomized CuCrNb alloy powder is prepared by high-speed rotation. Step 2: Make the sleeve mold: Make the corresponding sleeve mold according to the shape and size of the conductive rod, and set it aside for later use; Step 3, Loading: Place the CuCrNb alloy powder prepared in Step 1 into the rubber sleeve mold, using a rubber sleeve with a diameter of 90mm and a length of 1000mm; Step 4, Cold Isostatic Pressing: Place the loaded rubber sleeve mold into the cold isostatic pressing furnace cavity for cold isostatic pressing. The pressure of cold isostatic pressing is 260MPa, and the holding time is 12min to obtain cold isostatic pressed bars. Step 5, Degassing and Sealing: The cold isostatically pressed bar stock is loaded into the cladding mold from Step 2, then placed in a heat treatment furnace and heated to 640°C. After removal, it is placed in a degassing device and degassed at high temperature for 14 hours using a vacuum pumping system until the vacuum degree inside the cladding mold reaches 1.5 × 10⁻⁶. -4 After Pa, the evacuation port of the casing mold is sealed by argon arc welding; Step 6, Hot Isostatic Pressing: Place the sealed and welded cladding mold into the hot isostatic pressing furnace cavity for hot isostatic pressing sintering at a temperature of 930℃, a pressure of 120MPa, and a time of 5h. Step 7: Remove the cladding mold: Use machining to remove the cladding mold to obtain copper-chromium-niobium alloy rods; Step 8: Machining the copper-chromium-niobium alloy rod according to the drawing requirements to obtain the copper-chromium-niobium conductive rod.

[0027] The material properties of the aforementioned copper-chromium-niobium conductive rods were tested, and the results are shown in Table 1 below: Table 1. Material property test table for copper-chromium-niobium conductive rods

[0028] As shown in Table 1 above, the copper-chromium-niobium conductive rod prepared by the method of this invention exhibits excellent physical and mechanical properties, including high hardness and high conductivity. Furthermore, the metallographic structure of the copper-chromium-niobium conductive rod was observed. Figure 2 As shown, the metallographic structure was found to be uniform. Meanwhile, a control group was set up. The "cold isostatic pressing" step was removed from the method of Example 1, and the material properties of the copper-chromium-niobium conductive rod prepared by the control method were tested. The results are shown in Table 2 below: Table 2 Material Property Test Table for Copper-Chromium-Niobium Conductive Rods

[0029] As can be seen from the results in Table 2 above, without using the combined cold isostatic pressing and hot isostatic pressing process (i.e., the control), the hardness and conductivity of the prepared copper-chromium-niobium conductive rod both decreased significantly. It is evident that the present invention can obtain copper-chromium-niobium conductive rods with higher hardness and conductivity by using the combined cold isostatic pressing and hot isostatic pressing process.

[0030] Example 2: The difference between this example and Example 1 is in step 4. Specifically, the plastic sleeve mold after loading is placed into the cold isostatic pressing furnace cavity for cold isostatic pressing. The pressure of cold isostatic pressing is 200MPa and the holding time is 5min to obtain cold isostatic pressed bar stock.

[0031] Example 3: The difference between this example and Example 1 is in step 4. Specifically, the plastic sleeve mold after loading is placed into the cold isostatic pressing furnace cavity for cold isostatic pressing. The pressure of cold isostatic pressing is 280MPa, and the holding time is 15min, to obtain cold isostatic pressed bar stock.

[0032] Example 4: This example differs from Example 1 in step 5. Specifically, the cold isostatically pressed bar stock is loaded into the cladding mold of step 2, and then placed in a heat treatment furnace and heated to 500°C.

[0033] Example 5: This example differs from Example 1 in step 5. Specifically, the cold isostatically pressed bar is loaded into the cladding mold of step 2, and then placed in a heat treatment furnace and heated to 700°C.

[0034] Example 6: This example differs from Example 1 in step 5. Specifically, after removal, the material is placed in a degassing device and degassed at high temperature for 12 hours using a vacuum pumping system until the vacuum degree inside the encapsulation mold reaches 1×10⁻⁶. -3 After Pa, the vent of the casing mold is sealed with argon arc welding.

[0035] Example 7: This example differs from Example 1 in step 5. Specifically, after removal, the material is placed in a degassing device and degassed at high temperature for 15 hours using a vacuum pumping system until the vacuum degree inside the encapsulation mold reaches 1×10⁻⁶. -4 After Pa, the vent of the casing mold is sealed with argon arc welding.

[0036] Example 8: The difference between this example and Example 1 is in step 6. Specifically, the sealed mold is placed in the hot isostatic pressing furnace cavity for hot isostatic pressing sintering at a temperature of 850°C, a pressure of 110 MPa, and a time of 4 hours.

[0037] Example 9: The difference between this example and Example 1 is in step 6. Specifically, the sealed mold is placed in the hot isostatic pressing furnace cavity for hot isostatic pressing sintering at a temperature of 1000℃, a pressure of 130MPa, and a time of 6h.

[0038] To verify the material properties of the copper-chromium-niobium conductive rods prepared under different process parameters, the material properties of the copper-chromium-niobium conductive rods prepared in Examples 2-9 were tested, and the results are shown in Table 3 below: Table 3 Material property test table for copper-chromium-niobium conductive rods

[0039] As can be seen from Table 3 above, adjusting the parameters of cold isostatic pressing, hot isostatic pressing, heating temperature of the heat treatment furnace, and degassing parameters has a certain impact on the material properties of the prepared copper-chromium-niobium conductive rod. By comparing Examples 2 and 3 with Example 1, it can be seen that reducing the pressure and holding time of cold isostatic pressing based on Example 1 resulted in a certain degree of decrease in the hardness and conductivity of the copper-chromium-niobium conductive rod. However, increasing the pressure and holding time of cold isostatic pressing based on Example 1 did not result in significant changes in the hardness and conductivity of the copper-chromium-niobium conductive rod. But from the perspective of economic efficiency, the parameter indicators of Example 1 are relatively better. A comparison of Examples 4 and 5 with Example 1 shows that, based on Example 1, lowering or raising the heating temperature of the heat treatment furnace resulted in a certain degree of reduction in the hardness and conductivity of the copper-chromium-niobium conductive rod. Therefore, the parameter indicators of Example 1 are relatively better. A comparison of Examples 6 and 7 with Example 1 shows that reducing the degassing time in Example 1 resulted in a certain degree of decrease in the hardness and conductivity of the copper-chromium-niobium conductive rod. However, extending the degassing time in Example 1 did not significantly change the hardness and conductivity of the copper-chromium-niobium conductive rod. From the perspective of economic efficiency, the parameters of Example 1 are relatively better. A comparison of Examples 8 and 9 with Example 1 shows that, based on Example 1, lowering or increasing the hot isostatic pressing sintering parameters resulted in a certain degree of decrease in the hardness and conductivity of the copper-chromium-niobium conductive rod. Therefore, the parameter indicators of Example 1 are relatively better.

[0040] Example 10: This example differs from Example 1 in step 6, which is calculated according to the following formula: X%={1-[(N0—N min ) / N max ]}×100% Where N0 is the actual pressure value of hot isostatic pressure, i.e., 120 MPa; N max This refers to the maximum pressure value within the pressure range, i.e., 130 MPa; N min This is the minimum pressure value within the pressure range, i.e., 110 MPa; With N0 equal to 120, we calculate X%≈92.3%; After the temperature of the hot isostatic pressing sintering reaches 930℃, the temperature is periodically and uniformly adjusted according to 92.3%~100% of the maximum temperature of 1000℃, i.e., 923℃~1000℃. The duration of each periodic uniform adjustment is 30 minutes, that is, the temperature is increased from 923℃ to 1000℃ at a uniform rate for 30 minutes, and then decreased from 1000℃ to 923℃ at a uniform rate for another 30 minutes. This cycle is repeated until the hot isostatic pressing sintering is completed. During this period, an ultrasonic external field is applied. The power of the ultrasonic external field is 110W~330W, the frequency is 20Hz, and the ultrasonic external field is modulated according to the periodic uniform adjustment. Specifically, it includes the following steps: 1) During the temperature rise from 923℃ to 1000℃, the power of the ultrasonic field-assisted heating decreased synchronously and at a constant rate from 330W to 110W over 30 minutes. 2) During the cooling process from 1000℃ to 923℃, the power of the ultrasonic field-assisted system increased synchronously and at a constant rate from 110W to 330W over 30 minutes.

[0041] Example 11: The difference between this example and Example 10 is that the duration of a single periodic uniform speed regulation is 20 minutes.

[0042] Example 12: The difference between this example and Example 10 is that the duration of a single periodic uniform speed regulation is 40 minutes.

[0043] To verify the material properties of copper-chromium-niobium conductive rods prepared under different hot isostatic pressing methods, the material properties of the copper-chromium-niobium conductive rods prepared in Examples 10-12 were tested, and the results are shown in Table 4: Table 4 Material Property Test Table for Copper-Chromium-Niobium Conductive Rods

[0044] As shown in Table 4 above, compared with Example 1, the hardness and conductivity of the copper-chromium-niobium conductive rod prepared by hot isostatic pressing in Example 10 were significantly improved. Therefore, the material properties of the copper-chromium-niobium conductive rod prepared by hot isostatic pressing can be improved by using temperature range variation and ultrasonic external field assistance. At the same time, by comparing Example 11, Example 12 and Example 10, it can be seen that by reducing the single duration of periodic uniform speed control in Example 10, i.e., the cooling and heating rate and the power increase and decrease rate are both higher, the hardness and conductivity of the copper-chromium-niobium conductive rod are reduced to a certain extent. On the other hand, by extending the single duration of periodic uniform speed control in Example 10, i.e., the cooling and heating rate and the power increase and decrease rate are both lower, the hardness of the copper-chromium-niobium conductive rod is improved, but the improvement is very small. The overall process time of Example 12 is significantly increased. From the perspective of economy, the parameter indicators of Example 10 are relatively better. Meanwhile, Control 1 and Control 2 were set up. Control 1 was based on the method of Example 10, but with temperature control within the range of 900℃ to 1000℃, while all other parameters remained unchanged. Control 2 was based on the method of Example 10, but with ultrasonic external field assistance at a constant power of 330W, while all other parameters remained unchanged. The material properties of the copper-chromium-niobium conductive rods prepared by Control 1 and Control 2 were tested, and the results are shown in Table 5. Table 5 Material property test table for copper-chromium-niobium conductive rods

[0045] As shown in Table 5 above, when the temperature range obtained by the above formula was not used for regulation, the hardness and conductivity of the copper-chromium-niobium conductive rod decreased significantly. When constant power was used for ultrasonic external field assistance, the hardness and conductivity of the copper-chromium-niobium conductive rod also decreased significantly. Therefore, the temperature range regulation and ultrasonic external field assistance provided by the method of this invention can effectively improve the material properties of the copper-chromium-niobium conductive rod and enhance its hardness and conductivity.

Claims

1. A method for preparing a high-strength, high-conductivity copper-chromium-niobium conductive rod, characterized in that, The process involves cold isostatic pressing of CuCrNb alloy powder into a rubber-sleeved mold, followed by degassing and sealing of the cold isostatically pressed bar into a cladding mold, and then hot isostatic pressing to obtain a copper-chromium-niobium alloy bar. Finally, it is machined to obtain a copper-chromium-niobium conductive rod. The steps include: Step 1, Atomization Powder Preparation: CuCrNb alloy powder is prepared by plasma rotating gas atomization; Step 2: Make the sleeve mold: Make the corresponding sleeve mold according to the shape and size of the conductive rod, and set it aside for later use; Step 3, Loading: Place the CuCrNb alloy powder prepared in Step 1 into the rubber sleeve mold; Step 4, Cold Isostatic Pressing: Place the loaded rubber sleeve mold into the cold isostatic pressing furnace cavity for cold isostatic pressing to obtain cold isostatic pressed bars; Step 5, Degassing and Sealing: The cold isostatically pressed bar stock is loaded into the cladding mold of Step 2, then placed in a heat treatment furnace for heating, and after being taken out, it is placed in a degassing device. A vacuum pumping system is used to degas and vacuum the bar stock at high temperature, and then the pumping port is sealed. Step 6, Hot Isostatic Pressing: Place the sealed and welded cladding mold into the hot isostatic pressing furnace cavity for hot isostatic pressing sintering at a temperature of 850-1000℃, a pressure of 110-130MPa, and a time of 4-6h. Step 7: Remove the cladding mold: Use machining to remove the cladding mold to obtain copper-chromium-niobium alloy rods; Step 8: Machining the copper-chromium-niobium alloy rod according to the drawing requirements to obtain the copper-chromium-niobium conductive rod; After the temperature of the hot isostatic pressing sintering reaches 850-950℃, the temperature is periodically and uniformly controlled according to X%~100% of the maximum temperature of 1000℃, with ultrasonic external field assistance during this period. The duration of each periodic uniform control is 20~40 minutes, and X% satisfies the following formula: X% = {1 - [(N0 - N min ) / N max ]} x 100% Where N0 is the actual pressure value of hot isostatic pressure; N max This refers to the maximum pressure value within the pressure range, i.e., 130 MPa; N min This is the minimum pressure value within the pressure range, i.e., 110 MPa; The ultrasonic external field assistance has a power of 110W~330W and a frequency of 20Hz, and the ultrasonic external field assistance is modulated according to periodic uniform velocity control, specifically including the following steps: 1) During the period from X% to 100%, the power of the ultrasonic field assistance decreased synchronously and at an average speed from 330W to 110W; 2) During the period from 100% to X%, the power of the ultrasonic field-assisted power increased synchronously from 110W to 330W.

2. The method for preparing a high-strength, high-conductivity copper-chromium-niobium conductive rod as described in claim 1, characterized in that, The atomization powder preparation is as follows: CuCrNb alloy powder is prepared by plasma rotation atomization method. The prepared CuCrNb alloy electrode rod is assembled into the feeding device, and the alloy is melted and prepared by high-speed rotation under high vacuum argon atmosphere to obtain gas atomized CuCrNb alloy powder.

3. The method for preparing a high-strength, high-conductivity copper-chromium-niobium conductive rod as described in claim 1, characterized in that, The heat treatment furnace is heated to 500~700℃.

4. The method for preparing a high-strength, high-conductivity copper-chromium-niobium conductive rod as described in claim 1, characterized in that, In the degassing equipment, a vacuum pumping system is used for high-temperature degassing for 12-15 hours until the vacuum degree inside the encapsulation mold reaches 1×10⁻⁶. -3 Pa ~ 1×10 -4 After Pa, the vent of the casing mold is sealed with argon arc welding.

5. The method for preparing a high-strength, high-conductivity copper-chromium-niobium conductive rod as described in claim 1, characterized in that, The pressure of the cold isostatic pressing is 200-280 MPa, and the holding time is 5-15 min; the pressure of the hot isostatic pressing is 110-130 MPa, the temperature is 850-1000℃, and the holding time is 4-6 h.

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