A copper-clad aluminum alloy wire and its high-speed wire drawing process

Abstract

The present invention discloses a copper-clad aluminum alloy wire and its high-speed wire drawing process, which relates to the technical field of metal material processing. In the present invention, the aluminum alloy material is first subjected to cryogenic treatment and ball milling. The grains are refined, resulting in an increase in the grain boundary area, enhancing the ability to resist deformation and improving the strength. During the cryogenic treatment, high-energy ball milling is combined, so that other nano-metal particles are transformed from a supersaturated solid solution to a true solid solution, enhancing the strength and overall stability of the aluminum alloy. After copper cladding and welding in the present invention, high-temperature treatment is immediately carried out. The solute boundary layer is relatively thick and the solute components are fully diffused, so that the welded part is more stable and not easily cracked. At the same time, during the cooling process after high-temperature treatment, reduction is carried out using ethanol, so that the oxides generated in the weld seam and the bubbles generated by the metallurgical reaction at high temperature are reduced, further improving the performance of the copper-clad aluminum alloy wire while ensuring conductivity. The copper-clad aluminum alloy wire prepared by the present invention has the effect of high mechanical properties.

Description

Technical Field

[0001] The present invention relates to the technical field of metal material processing, and particularly to a copper-clad aluminum alloy wire and its high-speed wire drawing process. Background Art

[0002] The bimetallic copper-clad aluminum wire is concentrically coated with a copper layer on the outer surface of the aluminum core wire, enabling the two metals to form an interatomic metallurgical bond at the interface to form an integral metal wire. While ensuring the signal transmission quality, the copper-clad aluminum wire combines the advantages of both copper and aluminum metals, and reduces the production cost of the cable. Using this copper-clad aluminum alloy wire in the cable can not only ensure the signal transmission quality but also save scarce copper resources, thereby reducing the production cost and weight of the cable.

[0003] For the copper-clad aluminum alloy wire, the improvement of its strength is achieved by increasing the magnesium content in the core aluminum alloy and increasing the cold drawing deformation amount. Inevitably, the improvement of fineness will lead to the reduction of mechanical properties. In addition, for the copper-clad aluminum wire and the copper-clad aluminum-magnesium alloy wire, since the core material is a low-magnesium aluminum-magnesium alloy, at a high drawing rate, due to the large strength difference between it and the surface copper material, it is impossible to draw it into a micro-thin wire with a diameter of less than 0.08 mm after being drawn to a certain specification size. Summary of the Invention

[0004] The purpose of the present invention is to provide a copper-clad aluminum alloy wire and its high-speed wire drawing process to solve the problems existing in the prior art.

[0005] To solve the above technical problems, the present invention provides the following technical solution: A copper-clad aluminum alloy wire, which is obtained by subjecting an aluminum alloy material to cryogenic treatment and ball milling, followed by high-temperature and ethanol fumigation treatment after copper strip cladding and welding, and then high-speed wire drawing.

[0006] Furthermore, a preparation process of a copper-clad aluminum alloy wire includes the following steps:

[0007] (1) Mix aluminum with other nano-metal particles according to a ratio, subject it to solution treatment at 460 - 480 °C for 1 - 4 h, then cool it by water quenching after completion, and then heat it up to 110 - 130 °C for aging treatment for 24 h, and finally perform cryogenic treatment for 12 - 24 h; after the cryogenic treatment is completed, maintain the temperature of the cryogenic treatment, and ball mill the aluminum alloy powder to obtain aluminum alloy powder;

[0008] (2) Melt the aluminum alloy powder at a high temperature of 660 - 700 °C, and after cooling, make it into an aluminum alloy rod; then conduct pre-tensile deformation, control the cross-sectional shrinkage rate of the pre-tensile deformation to be 25 - 35%, and obtain a pre-tensile aluminum alloy rod; pickle the pre-tensile aluminum alloy rod and the copper sheet together with hydrochloric acid, then wash it once with distilled water to wash away the residual hydrochloric acid, then soak it in water at 80 °C for 1 h, and then dry it at 50 °C for 2 h; for cladding welding, first polish the treated pre-tensile aluminum alloy rod again, and at the same time brush the copper strip, thoroughly remove the oil stains and oxide films on the surfaces of the pre-tensile aluminum alloy rod and the copper strip, while increasing the surface roughness of the pre-tensile aluminum alloy rod and the copper strip, and improving the bonding force between the pre-tensile aluminum alloy rod and the copper strip; then wrap the copper strip outside the pre-tensile aluminum alloy rod, and use a GTAW cladding welding machine to weld the lap joint of the copper-clad aluminum alloy rod.

[0009] (3) Conduct high-temperature treatment on the copper-clad aluminum alloy rod. First, evacuate the air and introduce nitrogen, then heat-treat the copper-clad aluminum alloy rod at 520 - 580 °C for 10 - 20 min. After the treatment, cool it down to 250 - 350 °C, replace the introduced nitrogen with a mixed gas of nitrogen and ethanol, react for 20 - 30 min, and then cool it to room temperature under normal temperature and pressure after the reaction; then conduct rough drawing, medium drawing, and fine drawing on the copper-clad aluminum alloy rod after high-temperature treatment. The rough drawing is: draw the copper-clad aluminum alloy rod on a wire drawing machine at a speed of 130 m / min until the diameter is 1 mm; the medium drawing is: adjust the drawing speed to 800 m / min and draw it until the diameter is 0.2 mm; the fine drawing is: adjust the drawing speed to 2500 m / min and draw it until the diameter of the copper-clad aluminum alloy wire is 0.06 mm; place the copper-clad aluminum alloy wire in a vacuum annealing furnace for annealing, and after cooling to room temperature, obtain the finished copper-clad aluminum alloy wire.

[0010] Further, the chemical composition mass percentages of the aluminum alloy in step (1) are: copper 0.04% - 0.06%, magnesium 0.2% - 0.3%, iron 0.1% - 0.2%, chromium 0.05% - 0.1%, silver 0.015% - 0.03%, titanium 0.005% - 0.015%, zinc 0.15% - 0.25%, manganese 0.15% - 0.20%, and the balance is aluminum.

[0011] Further, the cryogenic treatment in step (1) is to cool it to -190 °C using liquid nitrogen.

[0012] Further, the ball milling time in step (1) is 1 - 10 min, the ball-to-material ratio is 10:1, and the medium is steel balls.

[0013] Further, the length, width, and height of the pre-tensile aluminum alloy rod in step (2) are 3 mm * 3 mm * 10 mm.

[0014] Further, the thickness of the copper strip in step (2) is 0.8 - 1.2 mm.

[0015] Further, the flow rate of the gas introduced in step (3) is 400 - 600 ml / min.

[0016] Further, the volume ratio of nitrogen to ethanol introduced in step (3) is 2:1.

[0017] Further, the temperature of vacuum annealing in step (3) is 300 - 350 °C, and the annealing time is 2 - 3 h.

[0018] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0019] The present invention performs cryogenic treatment and ball milling on aluminum alloy materials, followed by high-temperature and ethanol fumigation treatment after copper strip cladding welding, and is prepared by high-speed wire drawing to achieve the effect of high mechanical properties.

[0020] First of all, cryogenic treatment can improve the properties of aluminum alloy materials. After treatment, relatively small grains and random textures formed during cryogenic treatment are formed. The refinement of grains leads to an increase in grain boundary area, enhancing the ability to resist deformation, thereby improving strength; when cryogenic treatment is combined with high-energy ball milling, during the ball milling process, countless short-range diffusion reaction couples can be formed, and there is a similar mixing mechanism to sputtering and ion implantation. Other metal nanoparticles are forced to mix at dislocations, grain boundaries, sub-grain boundaries, and grain surfaces of aluminum metal at low temperatures, enabling other nano-metal particles to transform from sub-solid solution to true solid solution, forming a compatible alloy system, greatly enhancing the strength and overall stability of aluminum alloy, making the yield rate higher during subsequent high-speed wire drawing, and the prepared copper-clad aluminum alloy wire has excellent mechanical properties;

[0021] Secondly, the microstructure of the aluminum alloy core wire material is uniform, the grains are tiny, and the adhesion to the copper cladding layer is good. However, during argon arc welding, high temperature easily promotes the formation of copper-aluminum alloy between copper and aluminum, which is distributed at the grain boundary interface, leading to the generation of cracks; therefore, the present invention immediately performs high-temperature treatment after copper cladding welding. At a specific temperature, the secondary dendrites grow slowly, the fusion between dendrite arms is relatively developed, and the dendrite spacing is small, and the solute boundary layer is relatively thick, and the solute composition is fully diffused, and the microsegregation is relatively small, so that the welding part is more stable and not easily cracked, and the mechanical properties of the prepared finished product are more optimized; at the same time, during the cooling process after high-temperature treatment, ethanol is used in combination with inert gas to reduce the copper-clad aluminum alloy rod, so that the oxides generated in the weld and the bubbles generated by the metallurgical reaction at high temperature are reduced, further improving the performance of the copper-clad aluminum alloy wire while ensuring conductivity. Specific Embodiments

[0022] Next, in combination with the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0023] Embodiment 1

[0024] (1) The mass percentages of the chemical components of the aluminum alloy: copper is 0.04%, magnesium is 0.2%, iron is 0.1%, chromium is 0.05%, silver is 0.015%, titanium is 0.005%, zinc is 0.15%, manganese is 0.15%, and the balance is aluminum; aluminum is mixed with other nano-metal particles according to the ratio, and it is solution-treated at 460°C for 1 h, then water-quenched and cooled, then heated to 110°C for aging treatment for 24 h, and finally cryogenic treatment is carried out for 12 h, and the temperature is lowered to -190°C with liquid nitrogen; after the cryogenic treatment is completed, the temperature of the cryogenic treatment is maintained, and the aluminum alloy powder is ball-milled. The ball-milling time is 1 min, the ball-to-material ratio is 10:1, and the medium is steel balls to obtain aluminum alloy powder;

[0025] (2) The aluminum alloy powder is melted at a high temperature of 660°C and made into an aluminum alloy rod after cooling; then pre-tensile deformation is carried out, and the cross-sectional shrinkage rate of the pre-tensile deformation is controlled to be 25% to obtain a pre-tensile aluminum alloy rod. The length, width, and height of the pre-tensile aluminum alloy rod are 3 mm * 3 mm * 10 mm; a copper strip with a thickness of 0.8 mm is selected. The pre-tensile aluminum alloy rod and the copper strip are pickled with hydrochloric acid together, then washed with distilled water once to wash away the residual hydrochloric acid, then washed and soaked in water at 80°C for 1 h, and then dried at 50°C for 2 h; for cladding welding, first, the treated pre-tensile aluminum alloy rod is polished again, and at the same time, the copper strip is brushed with bristles. While thoroughly removing the oil stains and oxide films on the surfaces of the pre-tensile aluminum alloy rod and the copper strip, the surface roughness of the pre-tensile aluminum alloy rod and the copper strip is increased to improve the bonding force between the pre-tensile aluminum alloy rod and the copper strip; then the copper strip is wrapped outside the pre-tensile aluminum alloy rod, and the lap joint of the copper-clad aluminum alloy rod is welded by a GTAW cladding welding machine;

[0026] (3) The copper-clad aluminum alloy rod is subjected to high-temperature treatment. First, air is exhausted and nitrogen is introduced. Then, the copper-clad aluminum alloy rod is treated at 520 °C for 10 min. After the treatment, the temperature is lowered to 250 °C, and the introduced nitrogen is replaced with a mixed gas of nitrogen and ethanol. The flow rate of the introduced gas is 400 ml / min, and the volume ratio of nitrogen to ethanol is 2:1. The reaction lasts for 20 min, and after the end, it is cooled to room temperature under normal temperature and pressure; then, the copper-clad aluminum alloy rod after high-temperature treatment is subjected to rough drawing, medium drawing, and fine drawing. The rough drawing is as follows: The copper-clad aluminum alloy rod is drawn on a wire drawing machine at a speed of 130 m / min until the diameter is 1 mm; the medium drawing is as follows: The drawing speed is adjusted to 800 m / min and drawn until the diameter is 0.2 mm. The fine drawing is as follows: The drawing speed is adjusted to 2500 m / min and drawn to a copper-clad aluminum alloy wire with a diameter of 0.06 mm; the copper-clad aluminum alloy wire is placed in a vacuum annealing furnace for annealing. The temperature of the vacuum annealing is 300 °C, and the annealing time is 2 h. After the end, it is cooled to normal temperature to obtain the finished copper-clad aluminum alloy wire.

[0027] Example 2

[0028] (1) The chemical composition mass percentages of the aluminum alloy are as follows: copper is 0.05%, magnesium is 0.25%, iron is 0.15%, chromium is 0.075%, silver is 0.0275%, titanium is 0.1%, zinc is 0.2%, manganese is 0.175%, and the balance is aluminum; aluminum and other nano-metal particles are mixed according to the ratio, and it is solutionized at 470 °C for 2.5 h. After the end, it is cooled by water quenching, and then the temperature is raised to 120 °C for aging treatment for 24 h. Finally, it is subjected to cryogenic treatment for 18 h, and the temperature is lowered to -190 °C using liquid nitrogen; after the cryogenic treatment ends, the temperature of the cryogenic treatment is maintained, and the aluminum alloy powder is ball-milled. The ball-milling time is 5 min, the ball-to-material ratio is 10:1, and the medium is steel balls to obtain the aluminum alloy powder.

[0029] (2) The aluminum alloy powder is melted at a high temperature of 680 °C and then made into an aluminum alloy rod after cooling; then, pre-tensile deformation is carried out, and the cross-sectional shrinkage rate of the pre-tensile deformation is controlled to be 30% to obtain a pre-tensile aluminum alloy rod. The pre-tensile aluminum alloy rod has a length, width, and height of 3 mm * 3 mm * 10 mm; a copper strip with a thickness of 1 mm is selected. The pre-tensile aluminum alloy rod and the copper sheet are pickled with hydrochloric acid together, and then washed once with distilled water to wash away the residual hydrochloric acid, and then washed and soaked in water at 80 °C for 1 h, and then dried at 50 °C for 2 h; for cladding welding, first, the treated pre-tensile aluminum alloy rod is polished again, and at the same time, the copper strip is brushed with bristles. While thoroughly removing the oil stains and oxide films on the surfaces of the pre-tensile aluminum alloy rod and the copper strip, the surface roughness of the pre-tensile aluminum alloy rod and the copper strip is increased to improve the bonding force between the pre-tensile aluminum alloy rod and the copper strip; then, the copper strip is wrapped around the outside of the pre-tensile aluminum alloy rod, and a GTAW cladding welding machine is used to weld the lap joint of the copper-clad aluminum alloy rod.

[0030] (3) The copper-clad aluminum alloy rod is subjected to high-temperature treatment. First, air is exhausted and nitrogen is introduced. Then, the copper-clad aluminum alloy rod is treated at 550 °C for 15 min. After the treatment, the temperature is lowered to 300 °C, and the introduced nitrogen is replaced with a mixed gas of nitrogen and ethanol. The flow rate of the introduced gas is 500 ml / min, and the volume ratio of nitrogen to ethanol is 2:1. The reaction lasts for 25 min, and after the end, it is cooled to room temperature under normal temperature and pressure; then, the copper-clad aluminum alloy rod after high-temperature treatment is subjected to rough drawing, medium drawing, and fine drawing. The rough drawing is as follows: The copper-clad aluminum alloy rod is drawn on a wire drawing machine at a speed of 130 m / min until the diameter reaches 1 mm; the medium drawing is as follows: The drawing speed is adjusted to 800 m / min and drawn until the diameter reaches 0.2 mm. The fine drawing is as follows: The drawing speed is adjusted to 2500 m / min and drawn until the diameter reaches 0.06 mm to obtain a copper-clad aluminum alloy wire; the copper-clad aluminum alloy wire is placed in a vacuum annealing furnace for annealing. The temperature of the vacuum annealing is 325 °C, and the annealing time is 2.5 h. After the end, it is cooled to normal temperature to obtain the finished copper-clad aluminum alloy wire.

[0031] Example 3

[0032] (1) The chemical composition mass percentages of the aluminum alloy are as follows: copper is 0.06%, magnesium is 0.3%, iron is 0.2%, chromium is 0.1%, silver is 0.03%, titanium is 0.015%, zinc is 0.25%, manganese is 0.20%, and the balance is aluminum; aluminum and other nano-metal particles are mixed according to the ratio, and it is solution-treated at 480 °C for 4 h. After the end, it is cooled by water quenching, and then the temperature is raised to 130 °C for aging treatment for 24 h. Finally, it is subjected to cryogenic treatment for 24 h, and the temperature is lowered to -190 °C using liquid nitrogen; after the cryogenic treatment ends, the temperature of the cryogenic treatment is maintained, and the aluminum alloy powder is ball-milled. The ball-milling time is 10 min, the ball-to-material ratio is 10:1, and the medium is steel balls to obtain aluminum alloy powder;

[0033] (2) The aluminum alloy powder is melted at a high temperature of 700 °C and cooled to form an aluminum alloy rod; then, pre-tensile deformation is carried out, and the cross-sectional shrinkage rate of the pre-tensile deformation is controlled to be 35% to obtain a pre-tensile aluminum alloy rod. The pre-tensile aluminum alloy rod has a length, width, and height of 3 mm * 3 mm * 10 mm; a copper strip with a thickness of 1.2 mm is selected. The pre-tensile aluminum alloy rod and the copper sheet are pickled with hydrochloric acid together, and then washed with distilled water once to wash away the residual hydrochloric acid. Then, it is washed and soaked in water at 80 °C for 1 h, and then dried at 50 °C for 2 h; for cladding and welding, first, the treated pre-tensile aluminum alloy rod is polished again, and at the same time, the copper strip is brushed with bristles. While thoroughly removing the oil stains and oxide films on the surfaces of the pre-tensile aluminum alloy rod and the copper strip, the surface roughness of the pre-tensile aluminum alloy rod and the copper strip is increased to improve the bonding force between the pre-tensile aluminum alloy rod and the copper strip; then, the copper strip is wrapped outside the pre-tensile aluminum alloy rod, and a GTAW cladding welding machine is used to weld the lap joint of the copper-clad aluminum alloy rod.

[0034] (3) Heat-treat the copper-clad aluminum alloy rod. First, evacuate the air and introduce nitrogen gas. Then, heat-treat the copper-clad aluminum alloy rod at 580 °C for 20 min. After the treatment, cool it down to 350 °C, replace the introduced nitrogen gas with a mixed gas of nitrogen and ethanol, with the gas flow rate being 600 ml / min and the volume ratio of nitrogen to ethanol being 2:1. React for 30 min, and then cool it to room temperature under normal temperature and pressure after the reaction. Then, perform rough drawing, medium drawing, and fine drawing on the heat-treated copper-clad aluminum alloy rod. The rough drawing is as follows: Draw the copper-clad aluminum alloy rod on a wire drawing machine at a speed of 130 m / min until the diameter reaches 1 mm. The medium drawing is as follows: Adjust the drawing speed to 800 m / min and draw until the diameter reaches 0.2 mm. The fine drawing is as follows: Adjust the drawing speed to 2500 m / min and draw until the diameter of the copper-clad aluminum alloy wire reaches 0.06 mm. Place the copper-clad aluminum alloy wire in a vacuum annealing furnace for annealing. The temperature of the vacuum annealing is 350 °C, and the annealing time is 3 h. After the annealing, cool it to room temperature to obtain the finished copper-clad aluminum alloy wire.

[0035] Comparative Example 1

[0036] The difference between Comparative Example 1 and Example 2 lies in step (1). Modify step (1) as follows: The chemical composition mass percentage of the aluminum alloy: copper is 0.05%, magnesium is 0.25%, iron is 0.15%, chromium is 0.075%, silver is 0.0275%, titanium is 0.1%, zinc is 0.2%, manganese is 0.175%, and the balance is aluminum. Mix aluminum with other nano-metal particles according to the ratio, perform solution treatment on it at 470 °C for 2.5 h. After the treatment, cool it by water quenching, and then raise the temperature to 120 °C for aging treatment for 24 h. After the treatment, perform ball milling on the aluminum alloy powder. The ball milling time is 5 min, the ball-to-material ratio is 10:1, and the medium is steel balls to obtain the aluminum alloy powder. The remaining steps are the same as those in Example 2.

[0037] Comparative Example 2

[0038] The difference between Comparative Example 2 and Example 2 lies in step (1). Modify step (1) as follows: The chemical composition mass percentage of the aluminum alloy: copper is 0.05%, magnesium is 0.25%, iron is 0.15%, chromium is 0.075%, silver is 0.0275%, titanium is 0.1%, zinc is 0.2%, manganese is 0.175%, and the balance is aluminum. Mix aluminum with other nano-metal particles according to the ratio, perform solution treatment on it at 470 °C for 2.5 h. After the treatment, cool it by water quenching, and then raise the temperature to 120 °C for aging treatment for 24 h. Finally, cool it to -190 °C with liquid nitrogen for 18 h of cryogenic treatment to obtain the aluminum alloy powder. The remaining steps are the same as those in Example 2.

[0039] Comparative Example 3

[0040] The difference between Comparative Example 5 and Example 2 lies in step (3). Step (3) is modified as follows: Heat the copper-clad aluminum alloy rod to 300 °C, introduce a mixed gas of nitrogen and ethanol, with the gas flow rate being 500 ml / min, the volume ratio of nitrogen to ethanol being 2:1, react for 25 min, and after completion, cool it to room temperature under normal temperature and pressure; then perform rough drawing, medium drawing, and fine drawing on the copper-clad aluminum alloy rod after high-temperature treatment. The rough drawing is as follows: Draw the copper-clad aluminum alloy rod on a wire drawing machine at a speed of 130 m / min until the diameter reaches 1 mm; the medium drawing is as follows: Adjust the drawing speed to 800 m / min and draw until the diameter reaches 0.2 mm; the fine drawing is as follows: Adjust the drawing speed to 2500 m / min and draw until a copper-clad aluminum alloy wire with a diameter of 0.06 mm is obtained; Place the copper-clad aluminum alloy wire in a vacuum annealing furnace for annealing, with the vacuum annealing temperature being 325 °C and the annealing time being 2.5 h, and after completion, cool it to normal temperature to obtain the finished copper-clad aluminum alloy wire; The remaining steps are the same as those in Example 2.

[0041] Comparative Example 4

[0042] The difference between Comparative Example 4 and Example 2 lies in step (3). Step (3) is modified as follows: Perform high-temperature treatment on the copper-clad aluminum alloy rod. First, evacuate the air and introduce nitrogen, and then treat the copper-clad aluminum alloy rod at 550 °C for 15 min. After the treatment is completed, cool it to room temperature under normal temperature and pressure; then perform rough drawing, medium drawing, and fine drawing on the copper-clad aluminum alloy rod after high-temperature treatment. The rough drawing is as follows: Draw the copper-clad aluminum alloy rod on a wire drawing machine at a speed of 130 m / min until the diameter reaches 1 mm; the medium drawing is as follows: Adjust the drawing speed to 800 m / min and draw until the diameter reaches 0.2 mm; the fine drawing is as follows: Adjust the drawing speed to 2500 m / min and draw until a copper-clad aluminum alloy wire with a diameter of 0.06 mm is obtained; Place the copper-clad aluminum alloy wire in a vacuum annealing furnace for annealing, with the vacuum annealing temperature being 325 °C and the annealing time being 2.5 h, and after completion, cool it to normal temperature to obtain the finished copper-clad aluminum alloy wire; The remaining steps are the same as those in Example 2.

[0043] Effect Example

[0044] The following Table 1 presents the performance analysis results of a copper-clad aluminum alloy wire using Examples 1 to 3 and Comparative Examples 1 to 4 of the present invention.

[0045] Table 1

[0046] Tensile strength (MPa) Elongation at break (%) Resistivity at 20 °C (Ω·m) Example 1 286 15.0 0.0200 Example 2 289 15.2 0.0201 Example 3 293 14.8 0.0217 Comparative Example 1 278 14.2 0.0211 Comparative Example 2 271 14.0 0.0216 Comparative Example 3 265 13.7 0.0215 Comparative Example 4 261 13.6 0.0213

[0047] From the comparison of the experimental data on the mechanical properties of the examples and the comparative examples, it can be found that the present invention subjects the aluminum alloy material to cryogenic treatment and ball milling. After the treatment, relatively small grains are formed and a random texture is formed during the cryogenic treatment. The refinement of the grains leads to an increase in the grain boundary area, enhancing the ability to resist deformation, thereby improving the strength. During the ball milling process, numerous short-range diffusion reaction couples can be formed, and there is a similar mixing mechanism to sputtering and ion implantation. Other metal nanoparticles are forced to mix at the dislocations, grain boundaries, sub-grain boundaries, and grain surfaces of aluminum metal at low temperatures, causing other nano-metal particles to transform from a sub-solid solution to a true solid solution, forming a compatible alloy system, greatly enhancing the strength and overall stability of the aluminum alloy, making the yield rate higher during subsequent high-speed wire drawing, and the prepared copper-clad aluminum alloy wire having excellent mechanical properties. Secondly, the material microstructure of the aluminum alloy core wire of the present invention is uniform, the grains are tiny, and the adhesion to the copper coating layer is good. However, during argon arc welding, high temperatures easily cause copper and aluminum to form copper-aluminum alloy, which is distributed at the grain boundary interface, resulting in the generation of cracks. Therefore, the present invention performs high-temperature treatment immediately after copper cladding welding. At a specific temperature, the secondary dendrites grow slowly, the fusion between dendrite arms is relatively developed, the dendrite spacing is small, the solute boundary layer is relatively thick, and the solute components are fully diffused, with relatively small microsegregation, so that the welded part is more stable and not easily cracked, and the mechanical properties of the prepared finished product are more optimized. At the same time, during the cooling process after high-temperature treatment. From the comparison of the experimental data on the resistivity of the examples and the comparative examples, it can be found that the present invention uses ethanol in combination with an inert gas to reduce the copper-clad aluminum alloy rod, so that the oxides generated in the weld and the bubbles generated by the metallurgical reaction at high temperatures are reduced, further improving the performance of the copper-clad aluminum alloy wire while ensuring conductivity.

[0048] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms. Therefore, in any regard, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present invention. Any reference signs in the claims should not be construed as limiting the claimed rights.

Claims

1. A copper-clad aluminum alloy wire, characterized in that: The copper-clad aluminum alloy wire is obtained by deep cooling and ball milling the aluminum alloy material, copper strip coating welding, followed by high temperature and ethanol fumigation, and high-speed wire drawing. The following steps are involved: (1) Aluminum and other nano-metal particles are mixed according to a ratio, and the solid solution is dissolved at 460-480°C for 1-4 hours. After the solution is dissolved, the solution is cooled by water quenching, and then the temperature is raised to 110-130°C for aging treatment for 24 hours. Finally, the solution is cryogenically treated for 12-24 hours. After the cryogenic treatment, the cryogenic treatment temperature is maintained and the aluminum alloy powder is ball-milled to obtain aluminum alloy powder. (2) The aluminum alloy powder is melted at a high temperature of 660-700°C and cooled to form an aluminum alloy rod; then pre-stretching deformation is performed, and the cross-sectional shrinkage rate of the pre-stretching deformation is controlled to be 25-35%, thereby obtaining a pre-stretched aluminum alloy rod; the pre-stretched aluminum alloy rod and the copper sheet are pickled with hydrochloric acid, then washed with distilled water once to wash away the residual hydrochloric acid, then washed and soaked in water at 80°C for 1 hour, and then dried at 50°C for 2 hours; after cladding welding, the copper-clad aluminum alloy rod is obtained; (3) The copper-clad aluminum alloy rod is subjected to high-temperature treatment. First, the air is exhausted and nitrogen is introduced. Then, the copper-clad aluminum alloy rod is treated at 520-580°C for 10-20 min. After the treatment, the temperature is lowered to 250-350°C. The nitrogen introduced is replaced with a mixed gas of nitrogen and ethanol. The reaction is carried out for 20-30 min. After the reaction, the rod is cooled to room temperature at room temperature and pressure. The drawn copper-clad aluminum alloy wire is placed in a vacuum annealing furnace for annealing. The vacuum annealing temperature is 300-350°C and the annealing time is 2-3 h. After the reaction, the rod is cooled to room temperature to obtain a finished copper-clad aluminum alloy wire.

2. The copper-clad aluminum alloy wire according to claim 1, characterized in that: The chemical components of the aluminum alloy in step (1) are as follows: 0.04% to 0.06% copper, 0.2% to 0.3% magnesium, 0.1% to 0.2% iron, 0.05% to 0.1% chromium, 0.015% to 0.03% silver, 0.005% to 0.015% titanium, 0.15% to 0.25% zinc, 0.15% to 0.20% manganese, and the balance is aluminum.

3. The copper-clad aluminum alloy wire according to claim 1, characterized in that: The cryogenic treatment in step (1) is performed by cooling the temperature to -190°C using liquid nitrogen.

4. The copper-clad aluminum alloy wire according to claim 1, characterized in that: In the step (1), the ball milling time is 1-10 min, the ball-to-material ratio is 10:1, and the medium is steel balls.

5. The copper-clad aluminum alloy wire according to claim 1, characterized in that: In the cladding welding in step (2), the treated pre-stretched aluminum alloy rod is first polished again, and the copper strip is brushed to thoroughly remove the oil and oxide film on the surface of the pre-stretched aluminum alloy rod and the copper strip, thereby increasing the roughness of the surface of the pre-stretched aluminum alloy rod and the copper strip and improving the bonding strength between the pre-stretched aluminum alloy rod and the copper strip; then the copper strip is clad on the outside of the pre-stretched aluminum alloy rod, and the overlap of the copper-clad aluminum alloy rod is welded using a sub-arc cladding welding machine.

6. The copper-clad aluminum alloy wire according to claim 5, characterized in that: The length, height and width of the pre-stretched aluminum alloy rod in step (2) are 3mm*3mm*10mm.

7. The process for preparing a copper-clad aluminum alloy wire according to claim 5, characterized in that: The thickness of the copper strip in step (2) is 0.8-1.2 mm.

8. The copper-clad aluminum alloy wire according to claim 1, characterized in that: The flow rate of the gas introduced in step (3) is 400-600 ml / min.

9. The copper-clad aluminum alloy wire according to claim 1, characterized in that: The volume ratio of nitrogen to ethanol introduced in step (3) is 2:

1.

10. The copper-clad aluminum alloy wire according to claim 1, characterized in that: The drawing process in step (3) is as follows: the copper-clad aluminum alloy rod after high temperature treatment is subjected to rough drawing, intermediate drawing and fine drawing. The rough drawing is as follows: the copper-clad aluminum alloy rod is drawn on a wire drawing machine at a speed of 130 m / min to a diameter of 1 mm; the intermediate drawing is as follows: the drawing speed is adjusted to 800 m / min to draw the rod to a diameter of 0.2 mm; and the fine drawing is as follows: the drawing speed is adjusted to 2500 m / min to draw the copper-clad aluminum alloy wire to a diameter of 0.06 mm.