A method for preparing Cu-Ta composite wire

Abstract

This invention discloses a method for preparing Cu-Ta composite wires, comprising: 1. ball milling and mixing Cu powder and Ta powder; 2. spark plasma sintering; 3. hot extrusion treatment; 4. primary rotary forging treatment; 5. heat treatment; 6. secondary rotary forging treatment; 7. drawing treatment followed by straightening and pickling to obtain Cu-Ta composite wires. This invention achieves a dense structure and good matching of the two-phase interface of Cu and Ta powders through a combination of powder spark plasma sintering, rotary forging, and drawing processes with heat treatment, improving the performance of Cu-Ta composite wires and obtaining high-strength, high-conductivity Cu-Ta composite wires with a uniform structure. This method is simple, highly operable, and low-cost, suitable for the early-stage preparation of composite long wires, and the product is applicable to the field of pulse magnets.

Description

Technical Field

[0001] This invention belongs to the field of metal alloy material processing technology, specifically relating to a method for preparing Cu-Ta composite wire. Background Technology

[0002] High-strength, high-conductivity copper-based composite materials are metallic materials that combine excellent electrical transport properties, mechanical properties, and thermal stability. They are currently widely used in various fields such as high-pulse magnetic field conductors, changeover switches, electrical contactors, lead frames, and electronic devices. Among them, Cu-Nb, Cu-Ag, and Cu-Cr composite materials have achieved significant breakthroughs in application.

[0003] The most widespread application of this type of material is in wire. Currently, the conductor material used in pulse magnets is mainly Cu-Nb composite wire. The role of the Cu substrate is to ensure good conductivity, while the excellent mechanical properties mainly come from the contribution of the Nb core wire in the substrate. Since there is virtually no solid solution between copper and niobium, and it is difficult to form intermediate phase compounds, the main method for preparing this material is large plastic deformation. However, limited by the intrinsic properties of the Cu-Nb composite material itself and the limitations of the coordinated deformation ability between copper and niobium, Cu-Nb wires obtained by bundle drawing and multiple composite processes have reached their processing limits. While ensuring good conductivity, the material strength cannot be further improved through manufacturing processes and composition design. Taking Cu-Nb wires obtained by winding + bundle drawing and powder sleeve + bundle drawing as examples, the strength of single-core non-bundled composite wires is generally between 250MPa and 400MPa. In particular, although the winding + bundle drawing method has a slight advantage in performance, its manufacturing process is more cumbersome and complex, greatly increasing the cost of the finished wire.

[0004] Compared to Nb alloys, Ta alloys offer more significant advantages as reinforcing core wires. Tantalum and its alloys possess high density, high melting point, excellent corrosion resistance, low coefficient of thermal expansion, excellent high-temperature strength, and high ductility, making them increasingly valued and used in the manufacture of electronic devices and capacitors. Due to the superior properties of tantalum, researchers aim to expand and broaden its application areas by developing Cu-Ta alloy materials with even better performance. As high-pulse magnetic fields continue to develop, the performance requirements for conductor materials will become increasingly stringent, making the development of high-performance Cu-Ta composite materials of practical significance. With the further development of high-pulse magnetic fields, the gradual replacement of Cu-Nb microcomposite materials by Cu-Ta composite materials in high-pulse magnetic fields will become an inevitable trend. However, previous Cu-Ta composite materials often involved high-energy ball milling and cumulative rolling processes, which were complex and presented many obstacles in long-term preparation, making them unsuitable for mass production in related industries. Summary of the Invention

[0005] The technical problem to be solved by this invention is to provide a method for preparing Cu-Ta composite wires, addressing the shortcomings of the prior art. This method achieves a good, dense structure between copper and tantalum through powder discharge plasma sintering + rotary forging + drawing processes combined with heat treatment. This significantly optimizes the two-phase interface, improves the performance of the Cu-Ta composite wire, and yields a high-strength, high-conductivity Cu-Ta composite wire with a uniform structure. This solves the problem of complex preparation processes and difficulty in achieving high performance in existing Cu-Nb composite wire technologies.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a method for preparing Cu-Ta composite wire, characterized in that the method includes the following steps:

[0007] Step 1: Use a planetary ball mill to ball-mill and mix Cu powder and Ta powder to obtain Cu-Ta mixed powder;

[0008] Step 2: The Cu-Ta mixed powder obtained in Step 1 is subjected to spark plasma sintering to obtain Cu-Ta columnar alloy;

[0009] Step 3: The Cu-Ta columnar alloy obtained in Step 2 is subjected to hot extrusion to obtain Cu-Ta extruded bars;

[0010] Step 4: Perform a single rotary forging process on the Cu-Ta extruded bar obtained in Step 3 to obtain Cu-Ta single rotary forged wire;

[0011] Step 5: Heat treat the Cu-Ta single-forged wire obtained in Step 4;

[0012] Step 6: Perform a second rotary forging process on the Cu-Ta primary rotary forging wire after heat treatment in Step 5 to obtain Cu-Ta secondary rotary forging wire;

[0013] Step 7: The Cu-Ta secondary rotary forging wire obtained in Step 6 is drawn to obtain Cu-Ta drawn wire. After straightening and pickling, Cu-Ta composite wire is obtained.

[0014] The above-mentioned method for preparing Cu-Ta composite wire is characterized in that the particle sizes of Cu powder and Ta powder in step one are 5μm~15μm and 65μm~50μm, respectively. This invention controls the particle size of Cu powder and Ta powder based on the difference in deformability between Cu and Ta, which is beneficial to improving the deformability of the wire.

[0015] The above-mentioned method for preparing Cu-Ta composite wire is characterized in that the Cu powder and Ta powder in step one have a purity of 99.95% or higher.

[0016] The above-mentioned method for preparing Cu-Ta composite wire is characterized in that the ball milling and powder mixing process in step one uses a rotation speed of 350 rpm for 40 hours, a ball-to-powder mass ratio of 15:1, and the grinding balls include 8mm diameter grinding balls, 5mm diameter grinding balls, and 2mm diameter grinding balls in a quantity ratio of 3:5:2, and the ball milling atmosphere is argon. Typically, the powder loading operation before the ball milling and powder mixing process is carried out under argon protection, and the ball milling jar is always filled with argon atmosphere during the ball milling process to avoid oxidation of the Cu-Ta mixed powder.

[0017] The above-mentioned method for preparing Cu-Ta composite wire is characterized in that the mass fraction of Ta element in the Cu-Ta mixed powder in step one is 10% to 25%. This invention, by controlling the Ta element content, ensures the mechanical properties of the Cu-Ta composite wire while avoiding excessive Ta content that could affect its electrical conductivity.

[0018] The above-mentioned method for preparing Cu-Ta composite wire is characterized in that the discharge plasma sintering process in step two is as follows: first, heating to 600°C at a heating rate of 100°C / min, then heating to 950°C at a heating rate of 50°C / min, and holding at a pressure of 50MPa for 10min.

[0019] The above-mentioned method for preparing Cu-Ta composite wire is characterized in that the density of the Cu-Ta columnar alloy in step two is 97% to 99%. By controlling the density of the Cu-Ta columnar alloy, this invention facilitates interfacial bonding between particles and eliminates defects such as pores, thereby improving the mechanical and electrical properties of the Cu-Ta composite wire.

[0020] The above-mentioned method for preparing Cu-Ta composite wire is characterized in that, in step three, the Cu-Ta columnar alloy is subjected to a heat treatment at 900°C for 30 minutes before hot extrusion, and the die for hot extrusion is preheated to 400°C. The extrusion speed for hot extrusion is 5 mm / s. By heat-treating the Cu-Ta columnar alloy before hot extrusion and preheating the die, combined with controlling the extrusion speed, rapid cooling during hot extrusion is avoided, ensuring the smooth progress of the heat treatment process.

[0021] The above-mentioned method for preparing Cu-Ta composite wire is characterized in that the heat treatment temperature in step five is 700℃ and the holding time is 3h. By performing heat treatment after a single rotary forging process, work hardening caused by the rotary forging process is eliminated, avoiding core breakage due to work hardening during subsequent deformation. Typically, the entire heat treatment process is carried out in an argon atmosphere.

[0022] The above-mentioned method for preparing Cu-Ta composite wire is characterized in that: in step two, the diameter of the Cu-Ta columnar alloy is 30 mm and the height is 25 mm to 27 mm; in step three, the diameter of the Cu-Ta extruded bar is 7 mm; in step four, the diameter change of the Cu-Ta extruded bar during the first rotary forging process is: φ7.0 mm → φ6.6 mm → φ6.2 mm → φ5.9 mm → φ5.6 mm, with corresponding processing amounts of 11.1%, 11.8%, 9.4%, and 9.9%, respectively; in step six, the first Cu-Ta rotary forging process... The diameter changes of the wire are: φ5.6mm→φ5.3mm→φ5.0mm→φ4.7mm→φ4.4mm, with corresponding processing amounts of 9.9%, 10.4%, 11.0%, 11.6%, and 12.3%, respectively. During the drawing process described in step seven, the diameter changes of the Cu-Ta secondary rotary forging wire are: φ4.4mm→φ4.22mm→φ4.05mm→φ3.88mm→φ3.72mm→φ3.58mm→φ3.44mm, with corresponding processing amounts of 11.5%, 9.40%, 9.39%, 8.35%, and 8.18%, respectively.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] 1. This invention uses powder discharge plasma sintering + rotary forging + drawing process, combined with heat treatment, to form a good dense structure between Cu powder and Ta powder, and to form a good match between the two-phase interface, thereby improving the performance of Cu-Ta composite wire and obtaining a high-strength, high-conductivity Cu-Ta composite wire with a uniform structure.

[0025] 2. The Cu-Ta composite wire prepared by this invention achieves a high-strength Ta fiber structure with good dispersion effect, and the core wire has an average size of tens or hundreds of nanometers. Combined with heat treatment, a good interfacial bonding effect is formed between Cu and Ta particles, giving full play to the role of interfacial bonding in enhancing mechanical properties.

[0026] 3. In the Cu-Ta composite wire prepared by this invention, since Ta is extremely ductile, Cu-Ta is easier to refine than Cu-Nb, which reduces the difficulty of preparing composite wire. At the same time, since Ta has an exceptionally obvious hardening effect, the strengthening effect after processing is significantly higher than that of Nb. Therefore, compared with Nb fibers of Cu-Nb structure, the high-strength nano-Ta fibers formed in the Cu-Ta composite wire of this invention significantly improve the strength of Cu-Ta composite wire.

[0027] 4. Due to the excellent properties of Ta, including high shear and elastic modulus, excellent ductility, and corrosion resistance, the Cu-Ta composite wire prepared by this invention exhibits extremely high corrosion resistance, a small coefficient of thermal expansion, and high strength. At the same time, it has excellent tensile and electrical properties under relatively large cross-sectional dimensions. The process is simple, highly operable, and low in cost, making it suitable for mass production of wires and providing high-performance single-core base wires for further wire composites.

[0028] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0029] Figure 1 The images show the compressive stress-strain curves of the Cu-Ta composite wires prepared in Examples 1 to 4 of this invention.

[0030] Figure 2 This is a schematic diagram showing the change in conductivity with diameter φ during the deformation process of Cu-Ta composite wires prepared in Examples 1-4 of this invention. Detailed Implementation

[0031] Example 1

[0032] This embodiment includes the following steps:

[0033] Step 1: Using a planetary ball mill, 144g of Cu powder with a particle size of 5μm-15μm and a purity of 99.95% or higher and 16g of Ta powder with a particle size of 65μm-50μm and a purity of 99.95% or higher are ball-milled and mixed to obtain 160g of Cu-10%Ta mixed powder with a Ta element mass fraction of 10%. The ball milling and mixing process is carried out at a speed of 350rpm for 40h, with a ball-to-powder mass ratio of 15:1. The grinding balls include 8mm diameter grinding balls, 5mm diameter grinding balls, and 2mm diameter grinding balls in a quantity ratio of 3:5:2. The ball milling atmosphere is argon.

[0034] Step 2: The Cu-10%Ta mixed powder obtained in Step 1 is subjected to spark plasma sintering to obtain a Cu-10%Ta columnar alloy with a diameter of 30 mm and a height of 26 mm. The spark plasma sintering process is as follows: first, heat to 600℃ at a heating rate of 100℃ / min, then heat to 950℃ at a heating rate of 50℃ / min, and hold at a pressure of 50 MPa for 10 min.

[0035] The density of Cu-10%Ta columnar alloy was measured using the Archimedes displacement method and found to be above 97%.

[0036] Step 3: The Cu-10%Ta columnar alloy obtained in Step 2 is subjected to hot extrusion to obtain Cu-10%Ta extruded bars with a diameter of 7mm and a length of 48cm. Before the hot extrusion, the Cu-15%Ta columnar alloy is subjected to heat treatment at 900℃ for 30min, and the hot extrusion die is preheated to 400℃. The extrusion speed of the hot extrusion is 5mm / s, and the extrusion ratio is approximately 18.

[0037] Step 4: Perform four passes of single-stage rotary forging on the Cu-10%Ta extruded bar obtained in Step 3 to obtain Cu-Ta single-stage rotary forged wire; the diameter of the Cu-10%Ta extruded bar changes during the four passes of single-stage rotary forging as follows: φ7.0mm→φ6.6mm→φ6.2mm→φ5.9mm→φ5.6mm, with corresponding processing amounts of 11.1%, 11.8%, 9.4%, and 9.9%, respectively;

[0038] Step 5: The Cu-10%Ta single-forged wire obtained in Step 4 is subjected to heat treatment at 700℃ and held for 3 hours under argon atmosphere protection.

[0039] Step Six: Perform six passes of secondary rotary forging on the Cu-10%Ta primary rotary forging wire after heat treatment in Step Five to obtain Cu-10%Ta secondary rotary forging wire; the diameter change of the primary Cu-10%Ta primary rotary forging wire during the four passes of secondary rotary forging is: φ5.6mm→φ5.3mm→φ5.0mm→φ4.7mm→φ4.4mm, with corresponding processing amounts of 9.9%, 10.4%, 11.0%, 11.6%, and 12.3%, respectively;

[0040] Step 7: The Cu-10%Ta secondary rotary forged wire obtained in Step 6 is subjected to 6 drawing passes to obtain Cu-10%Ta drawn wire. After straightening and pickling, Cu-10%Ta composite wire is obtained. During the 6 drawing passes, the diameter of the Cu-10%Ta secondary rotary forged wire changes as follows: φ4.4mm→φ4.22mm→φ4.05mm→φ3.88mm→φ3.72mm→φ3.58mm→φ3.44mm, with corresponding processing amounts of 11.5%, 9.40%, 9.39%, 8.35%, and 8.18%, respectively.

[0041] Testing revealed that the Cu-10%Ta composite wire prepared in this embodiment exhibited a yield strength of 368 MPa under tensile conditions, a tensile strength of 379 MPa, a yield strength of 365 MPa under compressive conditions, and a conductivity of 79.3% IACS. Figure 1 and Figure 2As shown; calculations show that the total processing rate of the Cu-10%Ta composite wire prepared in this embodiment is 98.3%.

[0042] Example 2

[0043] This embodiment includes the following steps:

[0044] Step 1: Using a planetary ball mill, 136g of Cu powder with a particle size of 5μm-15μm and a purity of 99.95% or higher and 24g of Ta powder with a particle size of 65μm-50μm and a purity of 99.95% or higher are ball-milled and mixed to obtain 160g of Cu-15%Ta mixed powder with a Ta element mass fraction of 15%. The ball milling and mixing process is carried out at a speed of 350rpm for 40h, with a ball-to-powder mass ratio of 15:1. The grinding balls include 8mm diameter grinding balls, 5mm diameter grinding balls, and 2mm diameter grinding balls in a quantity ratio of 3:5:2. The ball milling atmosphere is argon.

[0045] Step 2: The Cu-10%Ta mixed powder obtained in Step 1 is subjected to spark plasma sintering to obtain a Cu-15%Ta columnar alloy with a diameter of 30 mm and a height of 25 mm. The spark plasma sintering process is as follows: first, heat to 600℃ at a heating rate of 100℃ / min, then heat to 950℃ at a heating rate of 50℃ / min, and hold at a pressure of 50MPa for 10 min.

[0046] The density of Cu-15%Ta columnar alloy was measured using the Archimedes displacement method and found to be above 98%.

[0047] Step 3: The Cu-15%Ta columnar alloy obtained in Step 2 is subjected to hot extrusion to obtain Cu-15%Ta extruded bars with a diameter of 7mm and a length of 46cm. Before the hot extrusion, the Cu-15%Ta columnar alloy is subjected to heat treatment at 900℃ for 30min, and the hot extrusion die is preheated to 400℃. The extrusion speed of the hot extrusion is 5mm / s, and the extrusion ratio is approximately 18.

[0048] Step 4: Perform four passes of single-stage rotary forging on the Cu-15%Ta extruded bar obtained in Step 3 to obtain Cu-15%Ta single-stage rotary forged wire; the diameter change of the Cu-10%Ta extruded bar during the four passes of single-stage rotary forging is: φ7.0mm→φ6.6mm→φ6.2mm→φ5.9mm→φ5.6mm, with corresponding processing amounts of 11.1%, 11.8%, 9.4%, and 9.9%, respectively;

[0049] Step 5: The Cu-15%Ta single-forged wire obtained in Step 4 is subjected to heat treatment at a temperature of 700℃ and a holding time of 3h under argon atmosphere protection.

[0050] Step Six: Perform six passes of secondary rotary forging on the Cu-15%Ta primary rotary forging wire after heat treatment in Step Five to obtain Cu-15%Ta secondary rotary forging wire; the diameter change of the primary Cu-15%Ta primary rotary forging wire during the four passes of secondary rotary forging is: φ5.6mm→φ5.3mm→φ5.0mm→φ4.7mm→φ4.4mm, with corresponding processing amounts of 9.9%, 10.4%, 11.0%, 11.6%, and 12.3%, respectively;

[0051] Step 7: The Cu-15%Ta secondary rotary forged wire obtained in Step 6 is subjected to 6 drawing passes to obtain Cu-15%Ta drawn wire. After straightening and pickling, Cu-15%Ta composite wire is obtained. During the 6 drawing passes, the diameter of the Cu-15%Ta secondary rotary forged wire changes as follows: φ4.4mm→φ4.22mm→φ4.05mm→φ3.88mm→φ3.72mm→φ3.58mm→φ3.44mm, with corresponding machining allowances of 11.5%, 9.40%, 9.39%, 8.35%, and 8.18%, respectively.

[0052] Testing revealed that the Cu-15%Ta composite wire prepared in this embodiment exhibited a yield strength of 393 MPa under tensile conditions, a tensile strength of 411 MPa, a yield strength of 392 MPa under compressive conditions, and a conductivity of 74.3% IACS. Figure 1 and Figure 2 As shown; calculations show that the total processing rate of the Cu-10%Ta composite wire prepared in this embodiment is 98.5%.

[0053] Example 3

[0054] This embodiment includes the following steps:

[0055] Step 1: Using a planetary ball mill, 128g of Cu powder with a particle size of 5μm-15μm and a purity of 99.95% or higher and 32g of Ta powder with a particle size of 65μm-50μm and a purity of 99.95% or higher are ball-milled and mixed to obtain 160g of Cu-20%Ta mixed powder with a Ta element mass fraction of 20%. The ball milling and mixing process is carried out at a speed of 350rpm for 40h, with a ball-to-powder mass ratio of 15:1, and the grinding balls include 8mm diameter grinding balls, 5mm diameter grinding balls, and 2mm diameter grinding balls in a quantity ratio of 3:5:2. The ball milling atmosphere is argon.

[0056] Step 2: The Cu-20%Ta mixed powder obtained in Step 1 is subjected to spark plasma sintering to obtain a Cu-20%TaTa columnar alloy with a diameter of 30 mm and a height of 24 mm. The spark plasma sintering process is as follows: first, heat to 600℃ at a heating rate of 100℃ / min, then heat to 950℃ at a heating rate of 50℃ / min, and hold at a pressure of 50MPa for 10 min.

[0057] The density of Cu-20%Ta columnar alloy was measured using the Archimedes displacement method and found to be above 99%.

[0058] Step 3: The Cu-20%Ta columnar alloy obtained in Step 2 is subjected to hot extrusion to obtain Cu-20%Ta extruded bars with a diameter of 7mm and a length of 44cm. Before the hot extrusion, the Cu-20%Ta columnar alloy is subjected to heat treatment at 900℃ for 30min, and the hot extrusion die is preheated to 400℃. The extrusion speed of the hot extrusion is 5mm / s, and the extrusion ratio is approximately 18.

[0059] Step 4: Perform four passes of single-stage rotary forging on the Cu-20%Ta extruded bar obtained in Step 3 to obtain Cu-20%Ta single-stage rotary forged wire. During the four passes of single-stage rotary forging, the diameter of the Cu-20%Ta extruded bar changes as follows: φ7.0mm→φ6.6mm→φ6.2mm→φ5.9mm→φ5.6mm, with corresponding processing amounts of 11.1%, 11.8%, 9.4%, and 9.9%, respectively.

[0060] Step 5: The Cu-20%Ta single-forged wire obtained in Step 4 is subjected to heat treatment at a temperature of 700℃ and a holding time of 3h under argon atmosphere protection.

[0061] Step Six: Perform six passes of secondary rotary forging on the Cu-20%Ta primary rotary forging wire obtained from the heat-treated Cu-20%Ta secondary rotary forging wire. During the four passes of secondary rotary forging, the diameter of the primary Cu-20%Ta primary rotary forging wire changes as follows: φ5.6mm → φ5.3mm → φ5.0mm → φ4.7mm → φ4.4mm, with corresponding machining allowances of 9.9%, 10.4%, 11.0%, 11.6%, and 12.3%, respectively.

[0062] Step 7: The Cu-20%Ta secondary rotary forged wire obtained in Step 6 is subjected to 6 drawing passes to obtain Cu-20%Ta drawn wire. After straightening and pickling, Cu-20%Ta composite wire is obtained. During the 6 drawing passes, the diameter of the Cu-20%Ta secondary rotary forged wire changes as follows: φ4.4mm→φ4.22mm→φ4.05mm→φ3.88mm→φ3.72mm→φ3.58mm→φ3.44mm, with corresponding processing amounts of 11.5%, 9.40%, 9.39%, 8.35%, and 8.18%, respectively.

[0063] Testing revealed that the Cu-20%Ta composite wire prepared in this embodiment exhibited a yield strength of 430 MPa under tensile conditions, a tensile strength of 452 MPa, a yield strength of 451 MPa under compressive conditions, and a conductivity of 69.9% IACS. Figure 1 and Figure 2 As shown; calculations show that the total processing rate of the Cu-20%Ta composite wire prepared in this embodiment is 97.7%.

[0064] Example 4

[0065] This embodiment includes the following steps:

[0066] Step 1: Using a planetary ball mill, 120g of Cu powder with a particle size of 5μm-15μm and a purity of 99.95% or higher and 40g of Ta powder with a particle size of 65μm-50μm and a purity of 99.95% or higher are ball-milled and mixed to obtain 160g of Cu-25%Ta mixed powder with a Ta element mass fraction of 25%. The ball milling and mixing process is carried out at a speed of 350rpm for 40h, with a ball-to-powder mass ratio of 15:1. The grinding balls include 8mm diameter grinding balls, 5mm diameter grinding balls, and 2mm diameter grinding balls in a quantity ratio of 3:5:2. The ball milling atmosphere is argon.

[0067] Step 2: The Cu-25%Ta mixed powder obtained in Step 1 is subjected to spark plasma sintering to obtain a Cu-25%Ta columnar alloy with a diameter of 30 mm and a height of 24 mm. The spark plasma sintering process is as follows: first, heat to 600℃ at a heating rate of 100℃ / min, then heat to 950℃ at a heating rate of 50℃ / min, and hold at a pressure of 50MPa for 10 min.

[0068] The density of Cu-25%Ta columnar alloy was measured using the Archimedes displacement method and found to be above 98%.

[0069] Step 3: The Cu-25%Ta columnar alloy obtained in Step 2 is subjected to hot extrusion to obtain Cu-25%Ta extruded bars with a diameter of 7mm and a length of 44cm. Before the hot extrusion, the Cu-25%Ta columnar alloy is subjected to heat treatment at 900℃ for 30min, and the hot extrusion die is preheated to 400℃. The extrusion speed of the hot extrusion is 5mm / s, and the extrusion ratio is approximately 18.

[0070] Step 4: Perform four passes of single-stage rotary forging on the Cu-25%Ta extruded bar obtained in Step 3 to obtain Cu-25%Ta single-stage rotary forged wire; the diameter change of the Cu-25%Ta extruded bar during the four passes of single-stage rotary forging is: φ7.0mm→φ6.6mm→φ6.2mm→φ5.9mm→φ5.6mm, with corresponding processing amounts of 11.1%, 11.8%, 9.4%, and 9.9%, respectively;

[0071] Step 5: The Cu-25%Ta single-forged wire obtained in Step 4 is subjected to heat treatment at a temperature of 700℃ and a holding time of 3h under argon atmosphere protection.

[0072] Step Six: Perform six passes of secondary rotary forging on the Cu-25%Ta primary rotary forging wire obtained from the heat-treated Cu-25%Ta secondary rotary forging wire. During the four passes of secondary rotary forging, the diameter of the primary Cu-25%Ta primary rotary forging wire changes as follows: φ5.6mm → φ5.3mm → φ5.0mm → φ4.7mm → φ4.4mm, with corresponding machining allowances of 9.9%, 10.4%, 11.0%, 11.6%, and 12.3%, respectively.

[0073] Step 7: The Cu-25%Ta secondary rotary forged wire obtained in Step 6 is subjected to 6 drawing passes to obtain Cu-25%Ta drawn wire. After straightening and pickling, Cu-25%Ta composite wire is obtained. During the 6 drawing passes, the diameter of the Cu-25%Ta secondary rotary forged wire changes as follows: φ4.4mm→φ4.22mm→φ4.05mm→φ3.88mm→φ3.72mm→φ3.58mm→φ3.44mm, with corresponding processing amounts of 11.5%, 9.40%, 9.39%, 8.35%, and 8.18%, respectively.

[0074] Testing revealed that the Cu-25%Ta composite wire prepared in this embodiment exhibited a yield strength of 473 MPa under tensile conditions, a tensile strength of 498 MPa, a yield strength of 483 MPa under compressive conditions, and a conductivity of 68.1% IACS. Figure 1 and Figure 2As shown; calculations show that the total processing rate of the Cu-25%Ta composite wire prepared in this embodiment is 97.4%.

[0075] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Any simple modifications, alterations, and equivalent changes made to the above embodiments based on the inventive essence shall still fall within the protection scope of the present invention.

Claims

1. A method for preparing Cu-Ta composite wire, characterized in that, The method includes the following steps: Step 1: Use a planetary ball mill to ball-mill and mix Cu powder and Ta powder to obtain Cu-Ta mixed powder; the particle sizes of Cu powder and Ta powder are 5μm~15μm and 50μm~65μm, respectively; Step 2: The Cu-Ta mixed powder obtained in Step 1 is subjected to spark plasma sintering to obtain Cu-Ta columnar alloy; the diameter of the Cu-Ta columnar alloy is 30 mm and the height is 25 mm to 27 mm. Step 3: The Cu-Ta columnar alloy obtained in Step 2 is subjected to hot extrusion treatment to obtain Cu-Ta extruded rods; the diameter of the Cu-Ta extruded rods is 7mm; Step 4: Perform a single rotary forging process on the Cu-Ta extruded bar obtained in Step 3 to obtain Cu-Ta single-rotary forged wire; the diameter change of the Cu-Ta extruded bar during the single rotary forging process is: φ7.0mm→φ6.6mm→φ6.2mm→φ5.9mm→φ5.6mm, with corresponding processing amounts of 11.1%, 11.8%, 9.4%, and 9.9%, respectively; Step 5: Heat treat the Cu-Ta single-forged wire obtained in Step 4; the heat treatment temperature is 700℃ and the holding time is 3h. Step Six: Perform a second rotary forging process on the Cu-Ta primary rotary forged wire after heat treatment in Step Five to obtain Cu-Ta secondary rotary forged wire; the diameter change of the primary Cu-Ta rotary forged wire during the secondary rotary forging process is: φ5.6mm→φ5.3mm→φ5.0mm→φ4.7mm→φ4.4mm, with corresponding machining allowances of 9.9%, 10.4%, 11.0%, 11.6%, and 12.3%, respectively; Step 7: The Cu-Ta secondary rotary forging wire obtained in Step 6 is drawn to obtain Cu-Ta drawn wire. After straightening and pickling, Cu-Ta composite wire is obtained. During the drawing process, the diameter of the Cu-Ta secondary rotary forging wire changes as follows: φ4.4mm→φ4.22mm→φ4.05mm→φ3.88mm→φ3.72mm→φ3.58mm→φ3.44mm, with corresponding processing amounts of 11.5%, 9.40%, 9.39%, 8.35%, and 8.18%, respectively.

2. The method for preparing Cu-Ta composite wire according to claim 1, characterized in that, The Cu powder and Ta powder mentioned in step one have a purity of 99.95% or higher.

3. The method for preparing Cu-Ta composite wire according to claim 1, characterized in that, The ball milling and powder mixing process described in step one uses a rotation speed of 350 rpm and a time of 40 h. The ball-to-powder mass ratio is 15:1, and the grinding balls include 8 mm diameter grinding balls, 5 mm diameter grinding balls, and 2 mm diameter grinding balls in a quantity ratio of 3:5:

2. The ball milling atmosphere is argon.

4. The method for preparing Cu-Ta composite wire according to claim 1, characterized in that, The mass fraction of Ta element in the Cu-Ta mixed powder mentioned in step one is 10%~25%.

5. The method for preparing Cu-Ta composite wire according to claim 1, characterized in that, The discharge plasma sintering process described in step two is as follows: first, heat to 600°C at a heating rate of 100°C / min, then heat to 950°C at a heating rate of 50°C / min, and hold at a pressure of 50MPa for 10 minutes.

6. The method for preparing Cu-Ta composite wire according to claim 1, characterized in that, The density of the Cu-Ta columnar alloy described in step two is 97%~99%.

7. The method for preparing Cu-Ta composite wire according to claim 1, characterized in that, In step three, the Cu-Ta columnar alloy is subjected to a heat treatment at 900°C for 30 minutes before hot extrusion, and the mold for hot extrusion is preheated to 400°C. The extrusion speed for hot extrusion is 5 mm / s.

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