High-strength and high-conductivity copper alloy wire and gradient extrusion preparation method

Abstract

The invention relates to a preparation method of a high-strength and high-conductivity copper alloy wire, which comprises the following steps of: performing gradient extrusion and extrusion under a high-temperature condition to obtain a copper rod with a uniform and fine equiaxed crystal structure; performing large-deformation extrusion under medium and low temperature conditions to obtain a copper rod with a streamline fibrous structure; and carrying out multi-pass drawing treatment to obtain the copper alloy wire which is in a long and thin fiber structure along the radial direction. The copper alloy wire has high tensile strength and high conductivity, and the contradiction that in the prior art, a copper alloy wire cannot meet high strength and high conductivity at the same time is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of metal processing, and in particular to a high-strength and high-conductivity copper alloy wire and a gradient extrusion preparation method thereof. Background Art

[0002] Copper alloys are essential materials widely used in the national economy. High-tech sectors such as transportation, aerospace, drones, and intelligent robotics are driving higher demands for their strength and conductivity. High-strength, high-conductivity copper alloy wires contribute to lightweight products and faster signal transmission. However, pure copper wires lack sufficient mechanical properties when processed into microfilaments, making them inadequate for use. There are two approaches to improving the strength of copper-based materials: composite and solid-solution. Composite methods offer significant advantages for improving copper's strength and conductivity, but processing them into microfilaments presents significant technical challenges. Solid-solution copper alloys are widely used to strengthen copper alloy microfilaments, but the strength and conductivity of copper alloys are in conflict. While increasing the content of solid-solution elements and cold deformation can improve wire strength, this also significantly reduces conductivity. This makes it impossible to simultaneously meet the performance requirements of both high strength and high conductivity.

[0003] Publication number CN117604319A discloses a high-strength, high-conductivity copper alloy wire and its preparation method. This method improves its mechanical properties by adding Zr and Cr elements to refine the grains and precipitate a network of Cr reinforcement phases. However, since it is a precipitation-type copper alloy, it faces significant technical difficulties in processing fine wires and is difficult to process into fine wires. Publication number CN113774229B discloses a processing technology for high-strength, high-conductivity, high-purity copper wire. This method improves the wire's grain size, eliminates its internal stress, and improves the copper wire's conductivity through continuous extrusion and repeated crystallization annealing, while controlling the gradual increase in crystallization annealing temperature and the holding time. However, it is difficult to effectively improve the wire's strength after multiple recrystallizations, and the presence of a large number of grain boundaries does not effectively improve the copper wire's strength and conductivity. Summary of the Invention

[0004] The present invention aims to address the shortcomings of the prior art by providing a gradient extrusion method for producing high-strength, high-conductivity copper alloy wire. The copper alloy wire of the present invention exhibits both high tensile strength and high conductivity, resolving the inability of prior art copper alloy wires to simultaneously achieve both high strength and high conductivity.

[0005] The purpose of the present invention is to adopt the following scheme to achieve: A method for preparing a high-strength and high-conductivity copper alloy wire comprises the following steps: 1) Ingot production: Weigh the components according to the ratio of high-strength and high-conductivity copper alloy wire, and melt and cast them into ingots of φ180~φ200mm; 2) First hot extrusion: The ingot is heated to 850-950℃, homogenized, and extruded into a copper rod with uniform and fine equiaxed crystal structure under an extrusion ratio of 10:1-20:1; 3) Second hot extrusion: The copper rod is heated to 200-300°C, kept warm, and extruded into a copper rod with a streamlined fibrous structure at an extrusion ratio of 10:1 to 40:1; 4) Drawing treatment: The copper rod is drawn through multiple passes to obtain a copper alloy wire having a slender fiber structure along the wire diameter.

[0006] The melting and casting in step 1) is carried out in a vacuum induction furnace with a vacuum degree of ≤5.0×10 -2 Pa, heating temperature is 1100℃-1300℃, holding time is 10-20min, and refining is done at least 3 times.

[0007] The homogenization treatment time in step 2) is 4 to 6 hours.

[0008] The diameter of the copper rod in step 2) is 50-60 mm, and the particle size of the equiaxed crystals of the copper rod is 50-100 μm.

[0009] Step 3) The holding time is 1 to 2 hours.

[0010] Step 3) The diameter of the copper rod is 8-12 mm.

[0011] In step 4), when the diameter of the copper rod to be drawn is ≥3mm, the deformation of each drawing pass is 15%-25%, and the drawing speed is 10-50m / min; when the diameter of the copper rod is 0.9mm≤<3mm, the deformation of each drawing pass is 10%-15%, and the drawing speed is 50-400m / min.

[0012] The copper alloy wire contains copper, tin, rare earth elements, and transition metal elements. The mass percentage of each component is tin: 0.05-0.45%, rare earth elements: 0.005-0.020%, transition metal elements: 0.005-0.020%, and copper is the balance.

[0013] The rare earth elements include one or more of La, Ce, and Y; and the transition metal elements include one or more of Cr, Zr, and Ti.

[0014] The copper used is oxygen-free copper with a purity of more than 99.99%.

[0015] The advantages of the present invention are: 1. The method of the present invention uses high-temperature hot extrusion (extrusion ratio of 10:1 to 20:1). At high temperatures (850°C to 950°C), the dislocation deformation generated by extrusion drives the dynamic recrystallization of the copper alloy, forming a uniform and fine (50-100 μm) equiaxed grain structure, achieving fine grain strengthening, providing a certain strength for the material, and laying the foundation for subsequent fibrous structure. At the same time, the hot extrusion process eliminates the coarse columnar grain structure and internal defects (pores and dendritic segregation) generated by casting, thereby improving the plasticity and density of the material.

[0016] 2. This invention utilizes high-temperature extrusion (extrusion ratio of 10:1 to 40:1) at a medium-low temperature (200-300°C) to produce copper rods. The grains elongate along the extrusion direction, forming a distinct fibrous streamline structure with numerous deformation bands and dislocation entanglements, enhancing the material's strength. The subsequent drawing process further elongates the fibrous structure, resulting in a slender fiber structure along the wire diameter. This provides excellent strength for the wire, while also reducing grain boundaries and hindering electron movement in this direction. This reduces the effects of cold working on electrical conductivity and enhances the wire's electrical conductivity.

[0017] 3. The trace rare earth elements and transition elements in the copper alloy wire of the present invention function as follows: Trace rare earth elements readily react with harmful elements such as oxygen, sulfur, and lead in the copper matrix to form compounds, which are then removed from the matrix, purifying the matrix. They also provide heterogeneous nucleation sites, refining the grains and inhibiting grain growth. Trace transition elements have strong atomic binding energy with copper, reducing the grain boundary diffusion coefficient and inhibiting grain growth at high temperatures. The synergistic effect of these two trace elements is beneficial for controlling grain size during subsequent high-temperature extrusion and inhibiting recrystallization of fiber structures during medium- and low-temperature extrusion.

[0018] 4. The method of the present invention can also be used for solid solution high-strength and high-conductivity copper alloys, such as copper-magnesium alloys, copper-silver alloys, etc.

[0019] The method of the present invention adopts gradient extrusion, that is, extrusion under high temperature conditions to obtain a copper rod with a uniform and fine equiaxed crystal structure; large deformation extrusion under medium and low temperature conditions to obtain a copper rod with a streamlined fibrous structure; and after multiple drawing processes, a copper alloy wire with a slender fibrous structure along the wire diameter direction is obtained.

[0020] The applicant's experiments show that when the diameter of the high-strength and high-conductivity copper alloy wire prepared by the method of the present invention is 0.9 mm, the conductivity is greater than 86% IACS and the tensile strength is greater than 570 MPa. Therefore, the copper alloy wire has high tensile strength and high conductivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1This is the organizational diagram after the first extrusion of Example 1; Figure 2 This is the organizational diagram after the second extrusion of Example 1; Figure 3 This is the second extrusion organization diagram of Comparative Example 1 without adding trace elements; Figure 4 The radial fibers of the wire rod of Example 1; Figure 5 This is the radial fiber of the general process wire rod of Comparative Example 2. DETAILED DESCRIPTION

[0022] The following is a further description with reference to the accompanying drawings and specific implementations. Example 1

[0023] A method for preparing a high-strength and high-conductivity copper alloy wire by gradient extrusion comprises the following steps: 1) Weigh 99.83% oxygen-free copper rod, 0.15% tin, 0.01% rare earth La, and 0.01% Cr by mass and place them in a graphite crucible. In a vacuum induction furnace, draw the vacuum to ≤5.0×10 -2 Pa, start heating, heat to 1200℃±20℃ and keep warm for 15min, repeat refining 3 times, and pour into φ180mm water-cooled copper mold; 2) After the ingot is homogenized at 900℃±10℃ for 4h, a φ50mm copper rod is extruded at an extrusion ratio of 12.96:1; the metallographic structure is as follows Figure 1 As shown, the grain size is 50 to 100 μm; 3) After the extruded φ50mm copper rod is kept at 250℃±5℃ for 1h, φ8mm copper rod is extruded at an extrusion ratio of 39:1; the metallographic structure is as follows Figure 2 As shown, it is a fibrous streamline structure; 4) The copper rod is drawn in multiple passes. When the diameter of the copper rod is ≥3mm, the deformation of each pass is 20% and the drawing speed is 40m / min. When the diameter of the copper rod is 0.9mm≤<3mm, the deformation of each pass is 15% and the drawing speed is 100m / min, and a copper alloy wire with a diameter of 0.9mm is obtained. Figure 4 As shown, it is a long fiber texture.

[0024] The test results show that the tensile strength of the high-strength and high-conductivity copper alloy wire prepared in Example 1 is 576 MPa, and the conductivity is 87.6% IACS. Example 2

[0025] A method for preparing a high-strength and high-conductivity copper alloy wire by gradient extrusion comprises the following steps: 1) Weigh 99.826% oxygen-free copper rod, 0.15% tin, 0.012% rare earth La+Ce+Y (ratio 1:1:1), and 0.012% Cr+Zr+Ti (ratio 1:1:1) and place them in a graphite crucible. In a vacuum induction furnace, evacuate to ≤5.0×10 -2 Pa, start heating, heat to 1200℃±20℃ and keep warm for 10min, repeat refining 3 times, and pour into φ200mm water-cooled copper mold; 2) After homogenizing the ingot at 900℃±10℃ for 4.5h, 60mm φ copper rods were extruded at an extrusion ratio of 11.11:1; 3) After the extruded φ60mm copper rod is kept at 300℃±5℃ for 1h, a φ12mm copper rod is extruded at an extrusion ratio of 25:1; 4) The copper rod is drawn in multiple passes. When the diameter of the copper rod is ≥3mm, the deformation of each pass is 20% and the drawing speed is 40m / min. When the diameter of the copper rod is 0.9mm≤<3mm, the deformation of each pass is 15% and the drawing speed is 100m / min, and a copper alloy wire with a diameter of 0.9mm is obtained. Figure 4 As shown, it is a long fiber texture.

[0026] The test results show that the tensile strength of the high-strength and high-conductivity copper alloy wire prepared in Example 2 is 585 MPa, and the conductivity is 87.5% IACS. Example 3

[0027] A method for preparing a high-strength and high-conductivity copper alloy wire by gradient extrusion comprises the following steps: 1) Weigh 99.78% oxygen-free copper rod, 0.20% tin, 0.01% rare earth La, and 0.01% Cr by mass and place them in a graphite crucible. In a vacuum induction furnace, draw the vacuum to ≤5.0×10 -2 Pa, start heating, heat to 1200℃±20℃ and keep warm for 15min, repeat refining 3 times, and pour into φ180mm water-cooled copper mold; 2) After homogenizing the ingot at 900℃±10℃ for 4h, 50mm φ copper rods were extruded at an extrusion ratio of 12.96:1; 3) After the extruded φ50mm copper rod is kept at 250℃±5℃ for 1h, a φ10mm copper rod is extruded at an extrusion ratio of 25:1; 4) The copper rod is subjected to multiple drawing passes. When the diameter of the copper rod is ≥3 mm, the deformation amount of each pass is 20% and the drawing speed is 30 m / min. When the diameter of the copper rod is 0.9 mm ≤ <3 mm, the deformation amount of each pass is 15% and the drawing speed is 200 m / min, thereby obtaining a copper alloy wire with a diameter of 0.9 mm.

[0028] The test results show that the tensile strength of the high-strength and high-conductivity copper alloy wire prepared in Example 3 is 586 MPa, and the conductivity is 87.3% IACS. Example 4

[0029] A method for preparing a high-strength and high-conductivity copper alloy wire by gradient extrusion comprises the following steps: 1) Weigh 99.78% oxygen-free copper rod, 0.20% tin, 0.01% rare earth La+Y (ratio 1:1), and 0.01% Cr+Ti (ratio 1:1) and place them in a graphite crucible. In a vacuum induction furnace, evacuate the crucible to a vacuum of ≤5.0×10 -2 Pa, start heating, heat to 1200℃±20℃ and keep warm for 10min, repeat refining 3 times, and pour into φ200mm water-cooled copper mold; 2) After homogenizing the ingot at 900℃±10℃ for 4.5h, 60mm φ copper rods were extruded at an extrusion ratio of 11.11:1; 3) After the extruded φ60mm copper rod is kept at 250℃±5℃ for 1h, a φ12mm copper rod is extruded at an extrusion ratio of 25:1; 4) The copper rod is subjected to multiple drawing passes. When the diameter of the copper rod is ≥3 mm, the deformation amount of each pass is 20% and the drawing speed is 30 m / min. When the diameter of the copper rod is 0.9 mm ≤ <3 mm, the deformation amount of each pass is 15% and the drawing speed is 200 m / min, thereby obtaining a copper alloy wire with a diameter of 0.9 mm.

[0030] The test results show that the tensile strength of the high-strength and high-conductivity copper alloy wire prepared in Example 4 is 591 MPa, and the conductivity is 87% IACS. Example 5

[0031] A method for preparing a high-strength and high-conductivity copper alloy wire by gradient extrusion comprises the following steps: 1) Weigh 99.73% oxygen-free copper rod, 0.25% tin, 0.01% rare earth La, and 0.01% Cr by mass and place them in a graphite crucible. In a vacuum induction furnace, evacuate the crucible to a vacuum of ≤5.0×10 -2 Pa, start heating, heat to 1200℃±20℃ and keep warm for 15min, repeat refining 3 times, and pour into φ180mm water-cooled copper mold; 2) After homogenizing the ingot at 900℃±10℃ for 4h, 50mm φ copper rods were extruded at an extrusion ratio of 12.96:1; 3) After the extruded φ50mm copper rod is kept at 250℃±5℃ for 1h, a φ10mm copper rod is extruded at an extrusion ratio of 25:1; 4) The copper rod is subjected to multiple drawing passes. When the diameter of the copper rod is ≥3 mm, the deformation amount of each pass is 20% and the drawing speed is 30 m / min. When the diameter of the copper rod is 0.9 mm ≤ <3 mm, the deformation amount of each pass is 15% and the drawing speed is 200 m / min, thereby obtaining a copper alloy wire with a diameter of 0.9 mm.

[0032] The test results show that the tensile strength of the high-strength and high-conductivity copper alloy wire prepared in Example 5 is 593 MPa, and the conductivity is 86.9% IACS. Example 6

[0033] A method for preparing a high-strength and high-conductivity copper alloy wire by gradient extrusion comprises the following steps: 1) Weigh 99.73% oxygen-free copper rod, 0.25% tin, 0.01% rare earth La+Ce (ratio 1:1), and 0.01% Zr+Cr (ratio 1:1) and place them in a graphite crucible. In a vacuum induction furnace, evacuate to ≤5.0×10 - 2 Pa, start heating, heat to 1200℃±20℃ and keep warm for 10min, repeat refining 3 times, and pour into φ200mm water-cooled copper mold; 2) After homogenizing the ingot at 900℃±10℃ for 4.5h, 50mm φ copper rods were extruded at an extrusion ratio of 16:1; 3) After the extruded φ50mm copper rod is kept at 300℃±5℃ for 1h, a φ10mm copper rod is extruded at an extrusion ratio of 25:1; 4) The copper rod is subjected to multiple drawing passes. When the diameter of the copper rod is ≥3 mm, the deformation amount of each pass is 20% and the drawing speed is 30 m / min. When the diameter of the copper rod is 0.9 mm ≤ <3 mm, the deformation amount of each pass is 15% and the drawing speed is 200 m / min, thereby obtaining a copper alloy wire with a diameter of 0.9 mm.

[0034] The test results show that the tensile strength of the high-strength and high-conductivity copper alloy wire prepared in Example 6 is 605 MPa, and the conductivity is 86.6% IACS. Example 7

[0035] A method for preparing a high-strength and high-conductivity copper alloy wire by gradient extrusion comprises the following steps: 1) Weigh 99.63% oxygen-free copper rod, 0.35% tin, 0.01% rare earth La, and 0.01% Cr by mass and place them in a graphite crucible. In a vacuum induction furnace, evacuate the crucible to a vacuum of ≤5.0×10 -2 Pa, start heating, heat to 1200℃±20℃ and keep warm for 15min, repeat refining 3 times, and pour into φ180mm water-cooled copper mold; 2) After homogenizing the ingot at 900℃±10℃ for 4h, 50mm φ copper rods were extruded at an extrusion ratio of 12.96:1; 3) After the extruded φ50mm copper rod is kept at 250℃±5℃ for 1h, a φ10mm copper rod is extruded at an extrusion ratio of 25:1; 4) The copper rod is subjected to multiple drawing passes. When the diameter of the copper rod is ≥3 mm, the deformation amount of each pass is 20% and the drawing speed is 30 m / min. When the diameter of the copper rod is 0.9 mm ≤ <3 mm, the deformation amount of each pass is 15% and the drawing speed is 200 m / min, thereby obtaining a copper alloy wire with a diameter of 0.9 mm.

[0036] The test results show that the tensile strength of the high-strength and high-conductivity copper alloy wire prepared in Example 7 is 610 MPa, and the conductivity is 86.3% IACS. Example 8

[0037] A method for preparing a high-strength and high-conductivity copper alloy wire by gradient extrusion comprises the following steps: 1) Weigh 99.63% oxygen-free copper rod, 0.35% tin, 0.015% rare earth Y+Ce (ratio 1:1), and 0.005% Zr+Cr (ratio 1:1) and place them in a graphite crucible. In a vacuum induction furnace, evacuate the crucible to a vacuum of ≤5.0×10 - 2 Pa, start heating, heat to 1200℃±20℃ and keep warm for 10min, repeat refining 3 times, and pour into φ200mm water-cooled copper mold; 2) After homogenizing the ingot at 900℃±10℃ for 5h, 50mm φ copper rods were extruded at an extrusion ratio of 16:1; 3) After the extruded φ50mm copper rod is kept at 300℃±5℃ for 1h, φ8mm copper rod is extruded at an extrusion ratio of 39:1; 4) The copper rod is subjected to multiple drawing passes. When the diameter of the copper rod is ≥3 mm, the deformation amount of each pass is 20% and the drawing speed is 30 m / min. When the diameter of the copper rod is 0.9 mm ≤ and <3 mm, the deformation amount of each pass is 15% and the drawing speed is 250 m / min, thereby obtaining a copper alloy wire with a diameter of 0.9 mm.

[0038] The test results show that the tensile strength of the high-strength and high-conductivity copper alloy wire prepared in Example 8 is 617 MPa, and the conductivity is 86.1% IACS. Example 9

[0039] A method for preparing a high-strength and high-conductivity copper alloy wire by gradient extrusion comprises the following steps: 1) Weigh 99.83% oxygen-free copper rod, 0.15% magnesium, 0.015% rare earth Y+Ce (ratio 1:1), and 0.005% Zr+Cr (ratio 1:1) and place them in a graphite crucible. In a vacuum induction furnace, evacuate to ≤5.0×10 - 2 Pa, start heating, heat to 1250℃±20℃ and keep warm for 10min, repeat refining 3 times, and pour into φ200mm water-cooled copper mold; 2) After homogenizing the ingot at 950℃±10℃ for 4h, 50mm φ copper rods were extruded at an extrusion ratio of 16:1; 3) After the extruded φ50mm copper rod is kept at 300℃±5℃ for 1h, a φ10mm copper rod is extruded at an extrusion ratio of 25:1; 4) The copper rod is subjected to multiple drawing passes. When the diameter of the copper rod is ≥3 mm, the deformation amount of each pass is 20% and the drawing speed is 30 m / min. When the diameter of the copper rod is 0.9 mm ≤ and <3 mm, the deformation amount of each pass is 15% and the drawing speed is 250 m / min, thereby obtaining a copper alloy wire with a diameter of 0.9 mm.

[0040] The test results show that the tensile strength of the high-strength and high-conductivity copper alloy wire prepared in Example 9 is 581 MPa, and the conductivity is 88.3% IACS. Example 10

[0041] A method for preparing a high-strength and high-conductivity copper alloy wire by gradient extrusion comprises the following steps: 1) Weigh 97.98% oxygen-free copper rod, 2.00% silver, 0.01% rare earth Y+Ce (ratio 1:1), and 0.01% Zr+Cr (ratio 1:1) and place them in a graphite crucible. In a vacuum induction furnace, evacuate to ≤5.0×10 - 2 Pa, start heating, heat to 1150℃±20℃ and keep warm for 10min, repeat refining 3 times, and pour into φ180mm water-cooled copper mold; 2) After homogenizing the ingot at 850℃±10℃ for 4h, 50mm φ copper rods were extruded at an extrusion ratio of 12.96:1; 3) After the extruded φ50mm copper rod is kept at 300℃±5℃ for 1h, a φ10mm copper rod is extruded at an extrusion ratio of 25:1; 4) The copper rod is subjected to multiple drawing passes. When the diameter of the copper rod is ≥3 mm, the deformation amount of each pass is 20% and the drawing speed is 30 m / min. When the diameter of the copper rod is 0.9 mm ≤ and <3 mm, the deformation amount of each pass is 15% and the drawing speed is 250 m / min, thereby obtaining a copper alloy wire with a diameter of 0.9 mm.

[0042] The test results show that the tensile strength of the high-strength and high-conductivity copper alloy wire prepared in Example 9 is 587 MPa, and the conductivity is 91.5% IACS. Comparative Example 1

[0043] 1) Weigh 99.85% oxygen-free copper rod and 0.15% tin by mass, place them in a graphite crucible, and evacuate the vacuum to ≤5.0×10 -2 Pa, start heating, heat to 1200℃±20℃ and keep warm for 15min, repeat refining 3 times, and pour into φ180mm water-cooled copper mold; 2) After homogenizing the ingot at 900℃±10℃ for 4h, 50mm φ copper rods were extruded at an extrusion ratio of 12.96:1; 3) After the extruded φ50mm copper rod is kept at 300℃±5℃ for 1h, φ8mm copper rod is extruded at an extrusion ratio of 39:1; 4) The copper rod is subjected to multiple drawing passes. When the diameter of the copper rod is ≥3 mm, the deformation amount of each pass is 20% and the drawing speed is 40 m / min. When the diameter of the copper rod is 0.9 mm ≤ <3 mm, the deformation amount of each pass is 15% and the drawing speed is 100 m / min, thereby obtaining a copper alloy wire with a diameter of 0.9 mm.

[0044] The test results show that the tensile strength of the copper alloy wire prepared in Comparative Example 1 is 536 MPa, the conductivity is 85.3% IACS, and the metallographic structure is as follows: Figure 3 shown.

[0045] Comparison of Comparative Example 1 with Example 1 ( Figure 3 and Figure 2 ), since there are no trace elements in the components, although hot extrusion at different temperatures is also performed in the preparation process, the rod material shows a certain degree of recovery recrystallization after the second extrusion, and the wire material does not have a slender fiber shape. The tensile strength and conductivity of the obtained copper alloy wire are both lower than those of Example 1-8. Comparative Example 2

[0046] 1) Weigh 99.83% oxygen-free copper rod, 0.15% tin, 0.01% rare earth La, and 0.01% Cr by mass and place them in a graphite crucible. In a vacuum induction furnace, draw the vacuum to ≤5.0×10 -2 Pa, start heating, heat to 1200℃±20℃ and keep warm for 15min, repeat refining 3 times, pour into φ180mm water-cooled copper mold, and use wire cutting to cut into small pieces for subsequent processing; 2) The alloy block is placed in the down-draw continuous casting machine and vacuumed to ≤5.0×10 -2Pa, filled with argon, started heating to 1200 ° C, kept warm for 20 minutes, the speed of the lead rod for the down-draw continuous casting was 100 mm / min, the temperature of the cooling water for the down-draw continuous casting was 25 ° C, the cooling water flow rate was 30 L / min, and continuous casting was carried out to form a copper rod with a diameter of 8 mm; 3) The copper rod is subjected to multiple drawing passes. When the diameter of the copper rod is ≥3 mm, the deformation amount of each pass is 20% and the drawing speed is 40 m / min. When the diameter of the copper rod is 0.9 mm ≤ <3 mm, the deformation amount of each pass is 15% and the drawing speed is 100 m / min, thereby obtaining a copper alloy wire with a diameter of 0.9 mm.

[0047] The test results show that the tensile strength of the copper alloy wire prepared in Comparative Example 2 is 513 MPa, the conductivity is 85.6% IACS, and the texture is as follows: Figure 5 As shown, the Figure 4 Compare, Figure 5 It is a dense short fiber structure, which means that Comparative Example 2 does not adopt the extrusion process and also has no slender fiber structure. The tensile strength and conductivity of the obtained copper alloy wire are lower than those of Examples 1-8.

[0048] Conclusion: The high-strength and high-conductivity copper-tin alloy wire prepared by the method of the present invention has a microstructure and texture showing slender fibers due to the addition of trace elements to the alloy composition and multiple hot extrusions. The copper alloy wire has both high tensile strength and high conductivity.

[0049] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications made to the present invention by those skilled in the art without departing from the spirit of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A high-strength and high-conductivity copper alloy wire and a gradient extrusion preparation method, characterized in that: The following steps are involved: 1) Ingot production: Weigh the components according to the ratio of high-strength and high-conductivity copper alloy wire, and melt and cast them into ingots of φ180~φ200mm; 2) First hot extrusion: The ingot is heated to 850-950℃, homogenized, and extruded into a copper rod with uniform and fine equiaxed crystal structure under an extrusion ratio of 10:1-20:1; 3) Second hot extrusion: The copper rod is heated to 200-300°C, kept warm, and extruded into a copper rod with a streamlined fibrous structure at an extrusion ratio of 10:1 to 40:1; 4) Drawing treatment: The copper rod is drawn through multiple passes to obtain a copper alloy wire having a slender fiber structure along the wire diameter.

2. The preparation method according to claim 1, wherein: The melting and casting in step 1) is carried out in a vacuum induction furnace with a vacuum degree of ≤5.0×10 -2 Pa, heating temperature is 1100℃-1300℃, holding time is 10-20min, and refining is done at least 3 times.

3. The preparation method according to claim 1, wherein: The homogenization treatment time in step 2) is 4 to 6 hours.

4. The preparation method according to claim 1, wherein: The diameter of the copper rod in step 2) is 50-60 mm, and the particle size of the equiaxed crystals of the copper rod is 50-100 μm.

5. The preparation method according to claim 1, wherein: Step 3) The holding time is 1 to 2 hours.

6. The preparation method according to claim 1, wherein: Step 3) The diameter of the copper rod is 8-12 mm.

7. The preparation method according to claim 1, wherein: In step 4), when the diameter of the copper rod to be drawn is ≥3mm, the deformation of each drawing pass is 15%-25%, and the drawing speed is 10-50m / min; when the diameter of the copper rod is 0.9mm≤<3mm, the deformation of each drawing pass is 10%-15%, and the drawing speed is 50-400m / min.

8. The preparation method according to claim 1, wherein: The copper alloy wire contains copper, tin, rare earth elements, and transition metal elements. The mass percentage of each component is tin: 0.05-0.45%, rare earth elements: 0.005-0.020%, transition metal elements: 0.005-0.020%, and copper is the balance.

9. The preparation method according to claim 8, characterized in that: The rare earth elements include one or more of La, Ce, and Y; and the transition metal elements include one or more of Cr, Zr, and Ti.

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