Preparation process of ultrafine copper conductor for new energy automobile

Abstract

The invention relates to the technical field of copper conductor preparation, in particular to a preparation process of an ultra-fine copper conductor for a new energy automobile. The preparation process of the ultrafine copper conductor for the new energy automobile comprises the following steps: firstly, preparing a copper alloy rod blank, and then carrying out fusion casting, solid solution, cooling deformation and aging treatment on the copper alloy rod blank to obtain a copper alloy rod blank; and then carrying out first-time wire drawing treatment, first-time intermediate annealing treatment, second-time wire drawing treatment, second-time intermediate annealing treatment, third-time wire drawing treatment, third-time intermediate annealing treatment and final annealing treatment on the copper alloy rod blank to obtain the finished product copper alloy superfine single-strand wire. And the finished copper alloy superfine single-strand wire is stranded in multiple strands to obtain the superfine micro-copper stranded conductor wire. The prepared ultra-fine copper conductor for the new energy automobile has the advantages of high conductivity, high strength and high deflection resistance, is comparable to foreign imported products, and can be made in China instead of imported products.

Description

Technical Field

[0001] The present invention relates to the technical field of copper conductor preparation, and particularly relates to a preparation process for ultra-fine copper conductors for new energy vehicles. Background Art

[0002] With the release of the "New Energy Vehicle Industry Development Plan", the new energy vehicle industry has developed rapidly. Copper alloy materials refer to alloys obtained by adding one or several other elements to pure copper, which are characterized by excellent electrical conductivity, thermal conductivity, corrosion resistance, wear resistance, high strength, and fatigue resistance, and can be used to manufacture high-voltage cable lines in new energy vehicles. High-voltage cables are mainly used in electric vehicle wiring harnesses, and the voltage they carry is about 600V.

[0003] The automotive wiring harness is the main carrier for controlling the functions of automotive electrical and electronic components, and is the blood vessels and nerves of the vehicle, providing power, transmitting, and feedback signals to each electronic component. A copper alloy high-voltage cable with high electrical conductivity, high strength, and high flexural resistance can improve the driving safety performance of new energy vehicles. However, such high-value-added copper alloy high-voltage cables mainly rely on imports from companies such as Sumitomo Electric, Hitachi Cable, Mitsubishi, and Furukawa. Currently, China has become a major consumer of high-strength and high-conductivity special copper conductors. However, due to the late start of research in the field of high-strength and high-conductivity special copper conductors in China, high-strength and high-conductivity special copper conductors have to rely on imports. Therefore, the present invention provides a preparation process for ultra-fine copper conductors for new energy vehicles. Summary of the Invention

[0004] In order to solve the problem that the existing high-strength and high-conductivity special copper conductors highly rely on imports, the present invention provides a preparation process for ultra-fine copper conductors for new energy vehicles.

[0005] The preparation process for ultra-fine copper conductors for new energy vehicles provided by the present invention is achieved through the following scheme:

[0006] A preparation process for ultra-fine copper conductors for new energy vehicles includes the following steps:

[0007] Step 1, preparation of copper alloy rod blanks: Mix copper alloy powder and surface-modified carbon nanotubes evenly to obtain a mixed alloy powder, and the content of surface-modified carbon nanotubes in the mixed alloy powder is 0.2-1.0 wt%.

[0008] The elements in the copper alloy powder by mass percentage are as follows: 0.05% - 0.15% of Ag, 0.05% - 0.50% of Nb, 0.01% - 0.10% of In, 0.02% - 0.08% of Si, 0.30% - 0.80% of Cr, 0.003% - 0.008% of Ti, 0.002% - 0.06% of Hf, 0.004% - 0.016% of Sc, the total content of inevitable impurities <0.15%, and the balance is Cu;

[0009] Step 2: The mixed alloy powder in Step 2 is melted and cast into a copper alloy rod blank with a diameter of 8 - 12 mm. The obtained copper alloy rod blank is subjected to solution treatment and aging treatment to obtain a formed copper alloy rod.

[0010] Step 3: The formed copper alloy rod with a diameter of 8 - 12 mm in Step 3 is subjected to the first wire drawing treatment and the first intermediate annealing treatment to obtain a copper alloy thick wire with a diameter of 3 - 6 mm.

[0011] Step 4: The copper alloy thick wire with a diameter of 3 - 6 mm is subjected to the second wire drawing treatment and the second intermediate annealing treatment to obtain a primary copper alloy fine wire with a diameter of 0.3 - 0.6 mm.

[0012] Step 5: The primary copper alloy fine wire with a diameter of 0.3 - 0.6 mm is subjected to the third wire drawing treatment and the third intermediate annealing treatment to obtain a semi-finished copper alloy ultra-fine single-strand wire with a diameter of 0.80 - 1.08 mm.

[0013] Step 6: The semi-finished copper alloy ultra-fine wire is subjected to a final annealing treatment to obtain a finished copper alloy ultra-fine single-strand wire. The finished copper alloy ultra-fine single-strand wire is used for multi-strand stranding to produce an ultra-fine copper stranded conductor wire.

[0014] In the present invention, the surface of the carbon nanotubes is modified with single-atom copper, which improves the compatibility between the carbon nanotubes and the copper alloy matrix. The carbon nanotubes can be uniformly dispersed in the copper alloy melt under the melting condition, thereby improving the conductivity, mechanical strength, and flexural resistance of the formed copper alloy rod. The formed copper alloy rod is comparable to the high-strength and high-conductivity special copper conductors imported from abroad. Combining with the multiple wire drawing and multiple intermediate annealing treatments + final annealing provided in the present invention can effectively avoid the problem of wire breakage during wire drawing. Finally, multi-strand stranding can produce an ultra-fine copper stranded conductor wire with high conductivity, high strength, and high flexural resistance, meeting the requirements of high-voltage cables for new energy vehicles.

[0015] The ultra-fine copper conductor for new energy vehicles prepared in the present invention has the advantages of high conductivity, high strength, and high flexural resistance, comparable to imported products from abroad, and can achieve domestic substitution for imports.

[0016] Preferably, the content of the surface-modified carbon nanotubes in the mixed alloy powder is 0.5 - 0.6 wt%.

[0017] By optimizing the content of the surface-modified carbon nanotubes, the overall conductivity of the ultra-fine copper conductor can be improved while ensuring its excellent wire drawing strength and flexural resistance.

[0018] Preferably, the surface-modified carbon nanotubes are single-atom copper-modified carbon nanotubes, the single-atom copper loading rate is 5 - 10 wt%, the tube diameter of the carbon nanotubes is 5 - 40 nm, the length is 0.5 - 20 nm, and the hydroxyl content is 2 - 3 wt%.

[0019] By adopting the above technical solutions, it can be ensured that the overall ultra-fine copper conductor has excellent conductivity.

[0020] Preferably, the solution treatment parameters in step two: heat up to 980 - 1060 °C and hold for 15 - 45 min.

[0021] Preferably, the solution treatment parameters in step two: heat up to 1020 - 1040 °C and hold for 25 - 30 min.

[0022] Preferably, the aging treatment parameters in step two: heat up to 420 - 480 °C and hold for 120 - 160 min.

[0023] By adopting the above technical solutions, it can be ensured the tensile strength and flexural performance of the copper alloy rod blank.

[0024] Preferably, in the first wire drawing treatment in step three, the angle α of the extrusion die used is 25 - 30°, and the processing deformation rate is 8 ± 0.5%; the first intermediate annealing parameters are to heat up to 840 - 860 °C and hold for 15 - 30 min.

[0025] Preferably, in the second wire drawing treatment in step four, the angle α of the extrusion die used is 25 - 30°, and the processing deformation rate is 5 ± 0.5%; the second intermediate annealing parameters are to heat up to 840 - 860 °C and hold for 15 - 30 min.

[0026] Preferably, in the third wire drawing treatment in step five, the angle α of the extrusion die used is 25 - 30°, and the processing deformation rate is 2 ± 0.5%; the third intermediate annealing parameters are to heat up to 840 - 860 °C and hold for 15 - 30 min.

[0027] Preferably, the final annealing treatment parameters: heat up to 900 - 960 °C and hold for 0.4 - 0.6 s.

[0028] By adopting the above technical solutions, an ultra-fine copper conductor for new energy vehicles with high conductivity, high strength, and high flexural resistance can be obtained, meeting the performance requirements of high-voltage cables for new energy vehicles.

[0029] In summary, the present invention has the following advantages:

[0030] 1. The ultra-fine copper conductor for new energy vehicles prepared in the present invention has the advantages of high conductivity, high strength, and high flexural resistance, comparable to imported products from abroad, and can achieve domestic substitution for imports.

[0031] 2. The present invention modifies the surface of carbon nanotubes with single-atom copper, improving the compatibility between carbon nanotubes and the copper alloy matrix. The carbon nanotubes can be uniformly dispersed in the copper alloy melt under molten conditions, thereby improving the conductivity, mechanical strength, and flexural resistance of the copper alloy rod billet. The copper alloy rod billet is comparable to the high-strength and high-conductivity special copper conductors imported from abroad. Combining with the multiple drawing and multiple intermediate annealing treatments + final annealing provided in the present invention can effectively avoid wire breakage during drawing. Finally, multi-strand stranding can produce an ultra-fine copper stranded conductor wire with high conductivity, high strength, and high flexural resistance, meeting the requirements of high-voltage cables for new energy vehicles.

[0032] 3. The preparation process of the present invention is relatively simple, facilitating mass production and market promotion. Detailed Embodiment

[0033] To further understand the present invention, the technical solution of the present invention will be described below in combination with examples and comparative examples.

[0034] Example

[0035] A preparation process for an ultra-fine copper conductor for new energy vehicles includes the following steps:

[0036] Step 1, preparation of a copper alloy rod billet: High-speed mixing of copper alloy powder and surface-modified carbon nanotubes to obtain a mixed alloy powder. The content of surface-modified carbon nanotubes in the mixed alloy powder is 0.2 - 1.0 wt%; preferably, the content of surface-modified carbon nanotubes in the mixed alloy powder is 0.5 - 0.6 wt%.

[0037] The surface-modified carbon nanotubes are single-atom copper-modified carbon nanotubes, with a single-atom copper loading rate of 5 - 10 wt%, a carbon nanotube diameter of 5 - 40 nm, a length of 0.5 - 20 nm, and a hydroxyl content of 2 - 3 wt%.

[0038] The elemental mass percentages of the copper alloy powder are as follows: 0.05% - 0.15% of Ag, 0.05% - 0.50% of Nb, 0.01% - 0.10% of In, 0.02% - 0.08% of Si, 0.30% - 0.80% of Cr, 0.003% - 0.008% of Ti, 0.002% - 0.06% of Hf, 0.004% - 0.016% of Sc, the total content of unavoidable impurities < 0.15%, and the balance is Cu.

[0039] Step 2: The mixed alloy powder in Step 2 is melted and cast into a copper alloy rod blank with a diameter of 8 - 12 mm. The obtained copper alloy rod blank is subjected to solution treatment: heated at 5 - 10 °C / min to 980 - 1060 °C and held for 15 - 45 min, and then aged: heated at 1 - 3 °C / min to 420 - 480 °C and held for 120 - 160 min to obtain a formed copper alloy rod;

[0040] Step 3: The formed copper alloy rod with a diameter of 8 - 12 mm in Step 3 is subjected to the first wire drawing treatment. The angle α of the extrusion die used in the first wire drawing treatment is 25 - 30°, and the processing deformation rate is 8 ± 0.5%. After the first wire drawing treatment, an on-line first intermediate annealing treatment is carried out. The first intermediate annealing parameters are heated at 5 - 10 °C / min to 840 - 860 °C and held for 15 - 30 min to obtain a copper alloy thick wire with a diameter of 3 - 6 mm;

[0041] Step 4: The copper alloy thick wire with a diameter of 3 - 6 mm is subjected to the second wire drawing treatment. The angle α of the extrusion die used in the second wire drawing treatment is 25 - 30°, and the processing deformation rate is 5 ± 0.5%. After the second wire drawing treatment, an on-line second intermediate annealing treatment is carried out. The second intermediate annealing parameters are heated at 5 - 10 °C / min to 840 - 860 °C and held for 15 - 30 min to obtain a primary fine copper alloy wire with a diameter of 0.3 - 0.6 mm;

[0042] Step 5: The primary fine copper alloy wire with a diameter of 0.3 - 0.6 mm is subjected to the third wire drawing treatment. The angle α of the extrusion die used in the third wire drawing treatment is 25 - 30°, and the processing deformation rate is 2 ± 0.5%. After the third wire drawing treatment, an on-line third intermediate annealing treatment is carried out. The third intermediate annealing parameters are heated at 5 - 10 °C / min to 840 - 860 °C and held for 15 - 30 min to obtain a semi-finished copper alloy ultra-fine single-strand wire with a diameter of 0.80 - 1.08 mm;

[0043] Step 6: The semi-finished copper alloy ultra-fine wire is subjected to a final annealing treatment, heated at 5 - 10 °C / min to 900 - 960 °C and held for 0.4 - 0.6 s to obtain a finished copper alloy ultra-fine single-strand wire. The finished copper alloy ultra-fine single-strand wire is used for multi-strand stranding to produce an ultra-fine copper stranded conductor wire.

[0044] Preparation Example

[0045] The elemental formula of the mass percentage of the copper alloy powder can be seen in Table 1 - 3.

[0046] Table 1: Elemental formula of the mass percentage of the copper alloy powder in Preparation Examples 1 - 7

[0047]

[0048] Table 2: Element Formulation of Mass Percentages of Copper Alloy Powders in Preparation Examples 8 - 14

[0049]

[0050] Table 3: Element Formulation of Mass Percentages of Copper Alloy Powders in Preparation Examples 15 - 20

[0051]

[0052] Preparation method of copper alloy powder: Place high - purity cathode electrolytic copper ingot (99.99%), copper - silver alloy (Ag - 10Cu, 99.99%, Beijing Ruichi High - Tech Co., Ltd.), copper - niobium alloy (CuNb5, 99.99%, Tianjin Hejifeng Metal Materials Co., Ltd.), copper - indium alloy (CuIn5, 4N, Zhongke Yannuo Beijing Technology Co., Ltd.), copper - silicon alloy (CuSi20 copper - silicon alloy, 99.9%, Jiangsu Xidike Metal Products Co., Ltd.), copper - chromium alloy (CuCr10 copper - chromium alloy, 99.99%, Suzhou Rongqian Rare Metal Products Co., Ltd.), copper - titanium alloy (CuTi20 copper - titanium alloy, 99.99%, Tianjin Hejifeng Metal Materials Co., Ltd.), copper - hafnium alloy (CuHf2, 99.99%, customized by Hebei Ruichi New Materials Co., Ltd.), copper - scandium alloy (Cu Sc, 99.99%, customized by Hebei Ruichi New Materials Co., Ltd.) in a melting furnace at 1090°C. After all raw materials are completely melted, refine, degas, and remove slag to obtain a copper alloy melt, and obtain copper alloy powder through spray method, with particle size D 50 = 12 - 16 μm.

[0053] Example 1: A preparation process for ultra - fine copper conductors used in new energy vehicles, comprising the following steps:

[0054] Step 1, preparation of copper alloy rod blanks: Prepare copper alloy powder according to the element formulation of the mass percentage of copper alloy powder provided in Preparation Example 1: Place high - purity cathode electrolytic copper ingot, copper - silver alloy, copper - niobium alloy, copper - indium alloy, copper - silicon alloy, copper - chromium alloy, copper - titanium alloy, copper - hafnium alloy, copper - scandium alloy in a melting furnace at 1090°C. After all raw materials are completely melted, refine, degas, and remove slag to obtain a copper alloy melt, and obtain copper alloy powder with particle size D 50 = 14.8 μm through spray method. Place 998 g of copper alloy powder and 2 g of surface - modified carbon nanotubes (single - atom copper - modified carbon nanotubes customized by Beijing Graphene Technology Research Institute, with a single - atom copper loading of 5.13 wt% and a carrier of industrial - grade multi - wall carbon nanotubes TNNF - 6 from Chengdu Organic Chemistry Co., Ltd., Chinese Academy of Sciences) in a high - speed stirring kettle, and mix at a high speed of 600 rpm for 1.0 h under argon protection to obtain a mixed - type alloy powder;

[0055] The preparation method of surface-modified carbon nanotubes is as follows: 0.50 g of industrial multi-walled carbon nanotubes TNNF-6 (provided by Chengdu Organic Chemistry Co., Ltd., Chinese Academy of Sciences, OD: 10 - 20 nm, length 5 - 20 microns, SSA > 120 m 2 / g) was dispersed in 1.0 L of distilled water and magnetically stirred at 200 rpm to obtain a graphene dispersion. Then, 4.0 g of potassium hydroxide was dissolved in 1.0 L of distilled water to obtain an aqueous potassium hydroxide solution. Under magnetic stirring at 200 rpm, the prepared aqueous potassium hydroxide solution was added dropwise to the graphene dispersion at a dropping rate of 2 drops / s. After the addition was completed, stirring was continued for 5 min. The water bath was heated to 80 °C and magnetically stirred at 200 rpm for 1 h, and then heated to 100 °C to remove the water in the solution, thus obtaining multi-walled carbon nanotubes TNNF-6 / KOH dry powder. 13.1 g of copper chloride CuCl2 was placed in a crucible (marked as crucible A), and 4.5 g of multi-walled carbon nanotubes TNNF-6 / KOH dry powder was placed in another crucible (marked as crucible B). Crucible A was placed in the upstream area of the tube furnace, and crucible B was placed in the downstream area of the tube furnace. Then, the tube furnace was sealed, and argon (purity 99.9%) was introduced into the tube furnace. Under an argon atmosphere, the upstream temperature zone of the tube furnace was heated from room temperature to 550 °C at a rate of 10 °C / min and maintained at 550 °C for 1.0 h of holding calcination. At the same time, under an argon atmosphere, the downstream temperature zone of the tube furnace was heated from room temperature to 550 °C at a rate of 10 °C / min and also maintained at 550 °C for 1.0 h of holding calcination, thereby obtaining a metal single-atom copper-doped industrial multi-walled carbon nanotubes TNNF-6 precursor. The obtained industrial multi-walled carbon nanotubes TNNF-6 precursor was added to 400 ml of dilute hydrochloric acid with a concentration of 1.0 ml / L and magnetically stirred at 200 rpm for 1 h. After vacuum filtration, it was washed three times with distilled water. The obtained solid powder was placed in a vacuum drying oven, the vacuum degree was adjusted to 100 Pa, the drying temperature was 125 °C, and vacuum drying treatment was carried out for 60 min. The obtained solid was transferred to a planetary ball mill, the grinding balls were zirconia, and the inner wall of the tank of the planetary ball mill was polytetrafluoroethylene. Argon (purity 99.9%) was introduced into the planetary ball mill. Under an argon atmosphere, it was stirred at 60 rpm for 10 min, stirred at 200 rpm for 5 min, stirred at 400 rpm for 5 min 10 min, and stirred at 60 rpm for 10 min, thus obtaining metal single-atom copper-doped industrial multi-walled carbon nanotubes TNNF-6 powder with an average particle size of 180 - 250 n for structural characterization. The atoms exist in the form of single copper atoms on the graphene surface. Inductively coupled plasma emission spectroscopy analysis shows that the doping amount of single copper atoms is about 5.13 wt%;

[0056] Step 2: Place the mixed alloy powder in Step 1 into a melting furnace at 1090 °C. After all raw materials are completely melted, refine, degas, and remove slag to obtain a copper alloy melt. Use the copper alloy melt to melt and cast into a copper alloy rod blank with a diameter of 8 mm. The obtained copper alloy rod blank is subjected to solution treatment: heat it to 1015 °C at a rate of 10 °C / min and hold for 25 min, and then perform aging treatment: heat it to 465 °C at a rate of 2 °C / min and hold for 2.0 h to obtain a formed copper alloy rod;

[0057] Step 3: Perform the first wire drawing treatment on the formed copper alloy rod with a diameter of 8 mm in Step 3. The angle α of the extrusion die used in the first wire drawing treatment is 30°, and the processing deformation rate is 8%. After the first wire drawing treatment, perform an on-line first intermediate annealing treatment. The first intermediate annealing parameters are to heat it to 860 °C at a rate of 10 °C / min and hold for 20 min to obtain a copper alloy thick wire with a diameter of 3.0 mm;

[0058] Step 4: Perform the second wire drawing treatment on the copper alloy thick wire with a diameter of 3.0 mm. The angle α of the extrusion die used in the second wire drawing treatment is 30°, and the processing deformation rate is 4.5%. After the second wire drawing treatment, perform an on-line second intermediate annealing treatment. The second intermediate annealing parameters are to heat it to 850 °C at a rate of 8 °C / min and hold for 25 min to obtain a primary copper alloy fine wire with a diameter of 0.40 mm;

[0059] Step 5: Perform the third wire drawing treatment on the primary copper alloy fine wire with a diameter of 0.40 mm. The angle α of the extrusion die used in the third wire drawing treatment is 30°, and the processing deformation rate is 1.5%. After the third wire drawing treatment, perform an on-line third intermediate annealing treatment. The third intermediate annealing parameters are to heat it to 840 °C at a rate of 5 °C / min and hold for 30 min to obtain a semi-finished copper alloy ultra-fine single-strand wire with a diameter of 0.106 mm;

[0060] Step 6: Perform the final annealing treatment on the semi-finished copper alloy ultra-fine wire with a diameter of 0.106 mm. Heat it to 948 °C at a rate of 10 °C / min and hold for 0.6 s to obtain a finished copper alloy ultra-fine single-strand wire. Use the finished copper alloy ultra-fine single-strand wire for multi-strand stranding to obtain a 42-strand ultra-fine copper stranded conductor wire.

[0061] The difference between Example 2 and Example 1 is as follows: Step 1: Preparation of the copper alloy rod blank: Prepare the copper alloy powder according to the elemental formula of the mass percentage of the copper alloy powder provided in Preparation Example 2: Place high-purity cathode electrolytic copper ingots, copper-silver alloys, copper-niobium alloys, copper-indium alloys, copper-silicon alloys, copper-chromium alloys, copper-titanium alloys, copper-hafnium alloys, and copper-scandium alloys in a melting furnace at 1090 °C. After all raw materials are completely melted, refine, degas, and remove slag to obtain a copper alloy melt, and obtain a particle size D by spray method 50Copper alloy powder with a diameter of 14.6 μm. Put 998 g of copper alloy powder and 2 g of surface-modified carbon nanotubes into a high-speed stirring kettle, and mix them at a high speed of 600 rpm for 1.0 h under argon protection to obtain the mixed alloy powder.

[0062] The difference between Example 3 and Example 1 lies in: Step 1, preparation of the copper alloy rod blank: Prepare copper alloy powder according to the elemental formula of the mass percentage of the copper alloy powder provided in Preparation Example 3: Put high-purity cathode electrolytic copper ingot, copper-silver alloy, copper-niobium alloy, copper-indium alloy, copper-silicon alloy, copper-chromium alloy, copper-titanium alloy, copper-hafnium alloy, and copper-scandium alloy into a melting furnace at 1090 °C. After all the raw materials are completely melted, refine, degas, and remove slag to obtain a copper alloy melt, and obtain copper alloy powder with a particle size D 50 Copper alloy powder with a diameter of 14.7 μm. Put 998 g of copper alloy powder and 2 g of surface-modified carbon nanotubes into a high-speed stirring kettle, and mix them at a high speed of 600 rpm for 1.0 h under argon protection to obtain the mixed alloy powder.

[0063] The difference between Example 4 and Example 1 lies in: Step 1, preparation of the copper alloy rod blank: Prepare copper alloy powder according to the elemental formula of the mass percentage of the copper alloy powder provided in Preparation Example 4: Put high-purity cathode electrolytic copper ingot, copper-silver alloy, copper-niobium alloy, copper-indium alloy, copper-silicon alloy, copper-chromium alloy, copper-titanium alloy, copper-hafnium alloy, and copper-scandium alloy into a melting furnace at 1090 °C. After all the raw materials are completely melted, refine, degas, and remove slag to obtain a copper alloy melt, and obtain copper alloy powder with a particle size D 50 Copper alloy powder with a diameter of 14.7 μm. Put 998 g and 2 g of surface-modified carbon nanotubes into a high-speed stirring kettle, and mix them at a high speed of 600 rpm for 1.0 h under argon protection to obtain the mixed alloy powder.

[0064] The difference between Example 5 and Example 1 lies in: Step 1, preparation of the copper alloy rod blank: Prepare copper alloy powder according to the elemental formula of the mass percentage of the copper alloy powder provided in Preparation Example 5: Put high-purity cathode electrolytic copper ingot, copper-silver alloy, copper-niobium alloy, copper-indium alloy, copper-silicon alloy, copper-chromium alloy, copper-titanium alloy, copper-hafnium alloy, and copper-scandium alloy into a melting furnace at 1090 °C. After all the raw materials are completely melted, refine, degas, and remove slag to obtain a copper alloy melt, and obtain copper alloy powder with a particle size D 50 Copper alloy powder with a diameter of 14.6 μm. Put 998 g of copper alloy powder and 2 g of surface-modified carbon nanotubes into a high-speed stirring kettle, and mix them at a high speed of 600 rpm for 1.0 h under argon protection to obtain the mixed alloy powder.

[0065] The difference between Example 6 and Example 1 lies in: Step 1, preparation of the copper alloy rod blank: Prepare the copper alloy powder according to the elemental formula of the mass percentage of the copper alloy powder provided in Preparation Example 6: Place high-purity cathode electrolytic copper ingots, copper-silver alloys, copper-niobium alloys, copper-indium alloys, copper-silicon alloys, copper-chromium alloys, copper-titanium alloys, copper-hafnium alloys, and copper-scandium alloys in a melting furnace at 1090 °C. After all the raw materials are completely melted, refine, degas, and remove slag to obtain a copper alloy melt, and obtain copper alloy powder with a particle size D 50 = 14.8 μm through a spray method. Place 998 g of the copper alloy powder and 2 g of surface-modified carbon nanotubes in a high-speed stirring kettle, and mix them at a high speed of 600 rpm for 1.0 h under argon protection to obtain a mixed alloy powder.

[0066] The difference between Example 7 and Example 1 lies in: Step 1, preparation of the copper alloy rod blank: Prepare the copper alloy powder according to the elemental formula of the mass percentage of the copper alloy powder provided in Preparation Example 7: Place high-purity cathode electrolytic copper ingots, copper-silver alloys, copper-niobium alloys, copper-indium alloys, copper-silicon alloys, copper-chromium alloys, copper-titanium alloys, copper-hafnium alloys, and copper-scandium alloys in a melting furnace at 1090 °C. After all the raw materials are completely melted, refine, degas, and remove slag to obtain a copper alloy melt, and obtain copper alloy powder with a particle size D 50 = 14.7 μm through a spray method. Place 998 g of the copper alloy powder and 2 g of surface-modified carbon nanotubes in a high-speed stirring kettle, and mix them at a high speed of 600 rpm for 1.0 h under argon protection to obtain a mixed alloy powder.

[0067] The difference between Example 8 and Example 1 lies in: Step 1, preparation of the copper alloy rod blank: Prepare the copper alloy powder according to the elemental formula of the mass percentage of the copper alloy powder provided in Preparation Example 1: Place high-purity cathode electrolytic copper ingots, copper-silver alloys, copper-niobium alloys, copper-indium alloys, copper-silicon alloys, copper-chromium alloys, copper-titanium alloys, copper-hafnium alloys, and copper-scandium alloys in a melting furnace at 1090 °C. After all the raw materials are completely melted, refine, degas, and remove slag to obtain a copper alloy melt, and obtain copper alloy powder with a particle size D 50 = 14.6 μm through a spray method. Place 996 copper alloy powder and 4 g of surface-modified carbon nanotubes in a high-speed stirring kettle, and mix them at a high speed of 600 rpm for 1.0 h under argon protection to obtain a mixed alloy powder.

[0068] The difference between Example 9 and Example 1 lies in: Step 1, preparation of the copper alloy rod blank: Prepare the copper alloy powder according to the elemental formula of the mass percentage of the copper alloy powder provided in Preparation Example 1: Place high-purity cathode electrolytic copper ingots, copper-silver alloys, copper-niobium alloys, copper-indium alloys, copper-silicon alloys, copper-chromium alloys, copper-titanium alloys, copper-hafnium alloys, and copper-scandium alloys in a melting furnace at 1090 °C. After all the raw materials are completely melted, refine, degas, and remove slag to obtain a copper alloy melt, and obtain copper alloy powder with a particle size D 50= 14.6 μm copper alloy powder. Put 995 copper alloy powder and 5.5 g of surface-modified carbon nanotubes into a high-speed stirring kettle, and mix them at a high speed of 600 rpm for 1.0 h under argon protection to obtain the mixed alloy powder.

[0069] The difference between Example 10 and Example 1 lies in: Step 1, preparation of the copper alloy rod blank: Prepare copper alloy powder according to the elemental formula of the mass percentage of the copper alloy powder provided in Preparation Example 1: Put high-purity cathode electrolytic copper ingot, copper-silver alloy, copper-niobium alloy, copper-indium alloy, copper-silicon alloy, copper-chromium alloy, copper-titanium alloy, copper-hafnium alloy, copper-scandium alloy into a melting furnace at 1090 °C. After all raw materials are completely melted, refine, degas, and remove slag to obtain a copper alloy melt, and obtain copper alloy powder with a particle size D 50 = 14.6 μm copper alloy powder. Put 992 copper alloy powder and 8 g of surface-modified carbon nanotubes into a high-speed stirring kettle, and mix them at a high speed of 600 rpm for 1.0 h under argon protection to obtain the mixed alloy powder.

[0070] The difference between Example 11 and Example 1 lies in: Step 1, preparation of the copper alloy rod blank: Prepare copper alloy powder according to the elemental formula of the mass percentage of the copper alloy powder provided in Preparation Example 1: Put high-purity cathode electrolytic copper ingot, copper-silver alloy, copper-niobium alloy, copper-indium alloy, copper-silicon alloy, copper-chromium alloy, copper-titanium alloy, copper-hafnium alloy, copper-scandium alloy into a melting furnace at 1090 °C. After all raw materials are completely melted, refine, degas, and remove slag to obtain a copper alloy melt, and obtain copper alloy powder with a particle size D 50 = 14.6 μm copper alloy powder. Put 990 copper alloy powder and 10 g of surface-modified carbon nanotubes into a high-speed stirring kettle, and mix them at a high speed of 600 rpm for 1.0 h under argon protection to obtain the mixed alloy powder.

[0071] The difference between Example 12 and Example 1 lies in: Step 2, put the mixed alloy powder in Step 2 into a melting furnace at 1090 °C. After all raw materials are completely melted, refine, degas, and remove slag to obtain a copper alloy melt. Use the copper alloy melt to melt and cast into a copper alloy rod blank with a diameter of 8 mm. The obtained copper alloy rod blank is subjected to solution treatment: heat up to 980 °C at a rate of 10 °C / min and hold for 30 min, then carry out cold deformation: the cold deformation amount is 80%; then carry out aging treatment: heat up to 480 °C at a rate of 2 °C / min and hold for 2 h to obtain the copper alloy rod blank.

[0072] The difference between Example 13 and Example 1 lies in: Step 2, placing the mixed alloy powder in Step 2 into a melting furnace at 1090 °C. After all raw materials are completely melted, refine, degas, and remove slag to obtain a copper alloy melt. Use the copper alloy melt for melt casting to form a copper alloy rod blank with a diameter of 8 mm. The obtained copper alloy rod blank undergoes solution treatment: heating to 1055 °C at a rate of 10 °C / min and holding for 20 min, followed by cold deformation: the cold deformation amount is 80%; then perform aging treatment: heating to 450 °C at a rate of 2 °C / min and holding for 2 h to obtain a formed copper alloy rod.

[0073] The difference between Example 14 and Example 1 lies in: Step 2, placing the mixed alloy powder in Step 2 into a melting furnace at 1090 °C. After all raw materials are completely melted, refine, degas, and remove slag to obtain a copper alloy melt. Use the copper alloy melt for melt casting to form a copper alloy rod blank with a diameter of 8 mm. The obtained copper alloy rod blank undergoes solution treatment: heating to 1025 °C at a rate of 10 °C / min and holding for 25 min, followed by cold deformation: the cold deformation amount is 80%; then perform aging treatment: heating to 475 °C at a rate of 2 °C / min and holding for 3 h to obtain a formed copper alloy rod.

[0074] The difference between Example 15 and Example 1 lies in: Step 2, placing the mixed alloy powder in Step 2 into a melting furnace at 1090 °C. After all raw materials are completely melted, refine, degas, and remove slag to obtain a copper alloy melt. Use the copper alloy melt for melt casting to form a copper alloy rod blank with a diameter of 8 mm. The obtained copper alloy rod blank undergoes solution treatment: heating to 1025 °C at a rate of 10 °C / min and holding for 25 min, followed by cold deformation: the cold deformation amount is 80%; then perform aging treatment: heating to 470 °C at a rate of 2 °C / min and holding for 4 h to obtain a formed copper alloy rod.

[0075] The difference between Example 16 and Example 1 lies in: Step 3, performing the first wire drawing treatment on the formed copper alloy rod with a diameter of 8 mm in Step 3. The angle α of the extrusion die used in the first wire drawing treatment is 30°, and the processing deformation rate is 7.5%. After completing the first wire drawing treatment, perform an on-line first intermediate annealing treatment. The first intermediate annealing parameters are heating to 840 °C at a rate of 8 °C / min and holding for 30 min to obtain a copper alloy thick wire with a diameter of 3.0 mm;

[0076] Step 4, performing the second wire drawing treatment on the copper alloy thick wire with a diameter of 3.0 mm. The angle α of the extrusion die used in the second wire drawing treatment is 30°, and the processing deformation rate is 5.0%. After completing the second wire drawing treatment, perform an on-line second intermediate annealing treatment. The second intermediate annealing parameters are heating to 840 °C at a rate of 8 °C / min and holding for 30 min to obtain a primary copper alloy fine wire with a diameter of 0.40 mm;

[0077] Step 5: Perform the third wire drawing treatment on the primary copper alloy fine wire with a diameter of 0.40 mm. In the third wire drawing treatment, the angle α of the extrusion die used is 30°, and the processing deformation rate is 2.5%. After the third wire drawing treatment, perform an on-line third intermediate annealing treatment. The parameters of the third intermediate annealing are to heat up to 860°C at a rate of 6°C / min and hold for 30 min to obtain a semi-finished copper alloy ultra-fine single-strand wire with a diameter of 0.107 mm.

[0078] The difference between Comparative Example 1 and Example 1 lies in: Step 1, preparation of the copper alloy rod blank: Prepare the copper alloy powder according to the elemental formula of the mass percentage of the copper alloy powder provided in Preparation Example 8: Place high-purity cathode electrolytic copper ingots, copper-silver alloys, copper-niobium alloys, copper-indium alloys, copper-silicon alloys, copper-chromium alloys, copper-titanium alloys, copper-hafnium alloys, and copper-scandium alloys in a melting furnace at 1090°C. After all the raw materials are completely melted, refine, degas, and remove slag to obtain a copper alloy melt, and obtain copper alloy powder with a particle size D 50 = 14.7 μm through a spray method. Place 998 copper alloy powder and 2 g of surface-modified carbon nanotubes in a high-speed stirring kettle and mix at a high speed of 600 rpm for 1.0 h under argon protection to obtain a mixed alloy powder.

[0079] The difference between Comparative Example 2 and Example 1 lies in: Step 1, preparation of the copper alloy rod blank: Prepare the copper alloy powder according to the elemental formula of the mass percentage of the copper alloy powder provided in Preparation Example 9: Place high-purity cathode electrolytic copper ingots, copper-silver alloys, copper-niobium alloys, copper-indium alloys, copper-silicon alloys, copper-chromium alloys, copper-titanium alloys, copper-hafnium alloys, and copper-scandium alloys in a melting furnace at 1090°C. After all the raw materials are completely melted, refine, degas, and remove slag to obtain a copper alloy melt, and obtain copper alloy powder with a particle size D 50 = 14.6 μm through a spray method. Place 998 copper alloy powder and 2 g of surface-modified carbon nanotubes in a high-speed stirring kettle and mix at a high speed of 600 rpm for 1.0 h under argon protection to obtain a mixed alloy powder.

[0080] The difference between Comparative Example 3 and Example 1 lies in: Step 1, preparation of the copper alloy rod blank: Prepare the copper alloy powder according to the elemental formula of the mass percentage of the copper alloy powder provided in Preparation Example 10: Place high-purity cathode electrolytic copper ingots, copper-silver alloys, copper-niobium alloys, copper-indium alloys, copper-silicon alloys, copper-chromium alloys, copper-titanium alloys, copper-hafnium alloys, and copper-scandium alloys in a melting furnace at 1090°C. After all the raw materials are completely melted, refine, degas, and remove slag to obtain a copper alloy melt, and obtain copper alloy powder with a particle size D 50 = 14.8 μm through a spray method. Place 998 copper alloy powder and 2 g of surface-modified carbon nanotubes in a high-speed stirring kettle and mix at a high speed of 600 rpm for 1.0 h under argon protection to obtain a mixed alloy powder.

[0081] The difference between Comparative Example 4 and Example 1 lies in: Step 1, preparation of the copper alloy rod blank: Prepare the copper alloy powder according to the elemental formula of the mass percentage of the copper alloy powder provided in Preparation Example 11: Place high-purity cathode electrolytic copper ingots, copper-silver alloy, copper-niobium alloy, copper-indium alloy, copper-silicon alloy, copper-chromium alloy, copper-titanium alloy, copper-hafnium alloy, and copper-scandium alloy in a melting furnace at 1090 °C. After all raw materials are completely melted, refine, degas, and remove slag to obtain a copper alloy melt. The copper alloy powder with a particle size D 50 = 14.7 μm is obtained by spray method. Place 998 copper alloy powder and 2 g of surface-modified carbon nanotubes in a high-speed stirring kettle, and mix at a high speed of 600 rpm for 1.0 h under argon protection to obtain the mixed alloy powder.

[0082] The difference between Comparative Example 5 and Example 1 lies in: Step 1, preparation of the copper alloy rod blank: Prepare the copper alloy powder according to the elemental formula of the mass percentage of the copper alloy powder provided in Preparation Example 12: Place high-purity cathode electrolytic copper ingots, copper-silver alloy, copper-niobium alloy, copper-indium alloy, copper-silicon alloy, copper-chromium alloy, copper-titanium alloy, copper-hafnium alloy, and copper-scandium alloy in a melting furnace at 1090 °C. After all raw materials are completely melted, refine, degas, and remove slag to obtain a copper alloy melt. The copper alloy powder with a particle size D 50 = 14.6 μm is obtained by spray method. Place 998 copper alloy powder and 2 g of surface-modified carbon nanotubes in a high-speed stirring kettle, and mix at a high speed of 600 rpm for 1.0 h under argon protection to obtain the mixed alloy powder.

[0083] The difference between Comparative Example 6 and Example 1 lies in: Step 1, preparation of the copper alloy rod blank: Prepare the copper alloy powder according to the elemental formula of the mass percentage of the copper alloy powder provided in Preparation Example 13: Place high-purity cathode electrolytic copper ingots, copper-silver alloy, copper-niobium alloy, copper-indium alloy, copper-silicon alloy, copper-chromium alloy, copper-titanium alloy, copper-hafnium alloy, and copper-scandium alloy in a melting furnace at 1090 °C. After all raw materials are completely melted, refine, degas, and remove slag to obtain a copper alloy melt. The copper alloy powder with a particle size D 50 = 14.6 μm is obtained by spray method. Place 998 copper alloy powder and 2 g of surface-modified carbon nanotubes in a high-speed stirring kettle, and mix at a high speed of 600 rpm for 1.0 h under argon protection to obtain the mixed alloy powder.

[0084] The difference between Comparative Example 7 and Example 1 lies in: Step 1, preparation of the copper alloy rod blank: Prepare the copper alloy powder according to the elemental formula of the mass percentage of the copper alloy powder provided in Preparation Example 14: Place high-purity cathode electrolytic copper ingots, copper-silver alloy, copper-niobium alloy, copper-indium alloy, copper-silicon alloy, copper-chromium alloy, copper-titanium alloy, copper-hafnium alloy, and copper-scandium alloy in a melting furnace at 1090 °C. After all raw materials are completely melted, refine, degas, and remove slag to obtain a copper alloy melt. The copper alloy powder with a particle size D 50Copper alloy powder with a diameter of 14.8 μm. Put 998 copper alloy powder and 2 g of surface-modified carbon nanotubes into a high-speed stirring kettle, and mix them at a high speed of 600 rpm for 1.0 h under argon protection to obtain the mixed alloy powder.

[0085] The difference between Comparative Example 8 and Example 1 lies in: Step 1, preparation of the copper alloy rod blank: Prepare the copper alloy powder according to the elemental formula of the mass percentage of the copper alloy powder provided in Preparation Example 15: Put high-purity cathode electrolytic copper ingot, copper-silver alloy, copper-niobium alloy, copper-indium alloy, copper-silicon alloy, copper-chromium alloy, copper-titanium alloy, copper-hafnium alloy, copper-scandium alloy into a melting furnace at 1090 °C. After all the raw materials are completely melted, refine, degas, and remove slag to obtain a copper alloy melt, and obtain copper alloy powder with a particle size D 50 Copper alloy powder with a diameter of 14.6 μm. Put 998 copper alloy powder and 2 g of surface-modified carbon nanotubes into a high-speed stirring kettle, and mix them at a high speed of 600 rpm for 1.0 h under argon protection to obtain the mixed alloy powder.

[0086] The difference between Comparative Example 9 and Example 1 lies in: Step 1, preparation of the copper alloy rod blank: Prepare the copper alloy powder according to the elemental formula of the mass percentage of the copper alloy powder provided in Preparation Example 16: Put high-purity cathode electrolytic copper ingot, copper-silver alloy, copper-niobium alloy, copper-indium alloy, copper-silicon alloy, copper-chromium alloy, copper-titanium alloy, copper-hafnium alloy, copper-scandium alloy into a melting furnace at 1090 °C. After all the raw materials are completely melted, refine, degas, and remove slag to obtain a copper alloy melt, and obtain copper alloy powder with a particle size D 50 Copper alloy powder with a diameter of 14.8 μm. Put 998 copper alloy powder and 2 g of surface-modified carbon nanotubes into a high-speed stirring kettle, and mix them at a high speed of 600 rpm for 1.0 h under argon protection to obtain the mixed alloy powder.

[0087] The difference between Comparative Example 10 and Example 1 lies in: Step 1, preparation of the copper alloy rod blank: Prepare the copper alloy powder according to the elemental formula of the mass percentage of the copper alloy powder provided in Preparation Example 17: Put high-purity cathode electrolytic copper ingot, copper-silver alloy, copper-niobium alloy, copper-indium alloy, copper-silicon alloy, copper-chromium alloy, copper-titanium alloy, copper-hafnium alloy, copper-scandium alloy into a melting furnace at 1090 °C. After all the raw materials are completely melted, refine, degas, and remove slag to obtain a copper alloy melt, and obtain copper alloy powder with a particle size D 50 Copper alloy powder with a diameter of 14.7 μm. Put 998 copper alloy powder and 2 g of surface-modified carbon nanotubes (single-atom copper-modified carbon nanotubes customized by Beijing Graphene Technology Research Institute Co., Ltd.) into a high-speed stirring kettle, and mix them at a high speed of 600 rpm for 1.0 h under argon protection to obtain the mixed alloy powder.

[0088] The difference between Comparative Example 11 and Example 1 lies in: Step 1, preparation of the copper alloy rod blank: Prepare the copper alloy powder according to the elemental formula of the mass percentage of the copper alloy powder provided in Preparation Example 18: Place high-purity cathode electrolytic copper ingots, copper-silver alloy, copper-niobium alloy, copper-indium alloy, copper-silicon alloy, copper-chromium alloy, copper-titanium alloy, copper-hafnium alloy, and copper-scandium alloy in a melting furnace at 1090 °C. After all the raw materials are completely melted, refine, degas, and remove slag to obtain a copper alloy melt. The copper alloy powder with a particle size D 50 = 14.6 μm is obtained by spray method. Place 998 copper alloy powder and 2 g of surface-modified carbon nanotubes (single-atom copper-modified carbon nanotubes customized by Beijing Graphene Technology Research Institute Co., Ltd.) in a high-speed stirring kettle, and mix at a high speed of 600 rpm for 1.0 h under argon protection to obtain the mixed alloy powder.

[0089] The difference between Comparative Example 12 and Example 1 lies in: Step 1, preparation of the copper alloy rod blank: Prepare the copper alloy powder according to the elemental formula of the mass percentage of the copper alloy powder provided in Preparation Example 19: Place high-purity cathode electrolytic copper ingots, copper-silver alloy, copper-niobium alloy, copper-indium alloy, copper-silicon alloy, copper-chromium alloy, copper-titanium alloy, copper-hafnium alloy, and copper-scandium alloy in a melting furnace at 1090 °C. After all the raw materials are completely melted, refine, degas, and remove slag to obtain a copper alloy melt. The copper alloy powder with a particle size D 50 = 14.7 μm is obtained by spray method. Place 998 copper alloy powder and 2 g of surface-modified carbon nanotubes (single-atom copper-modified carbon nanotubes customized by Beijing Graphene Technology Research Institute Co., Ltd.) in a high-speed stirring kettle, and mix at a high speed of 600 rpm for 1.0 h under argon protection to obtain the mixed alloy powder.

[0090] The difference between Comparative Example 13 and Example 1 lies in: Step 1, preparation of the copper alloy rod blank: Prepare the copper alloy powder according to the elemental formula of the mass percentage of the copper alloy powder provided in Preparation Example 20: Place high-purity cathode electrolytic copper ingots, copper-silver alloy, copper-niobium alloy, copper-indium alloy, copper-silicon alloy, copper-chromium alloy, copper-titanium alloy, copper-hafnium alloy, and copper-scandium alloy in a melting furnace at 1090 °C. After all the raw materials are completely melted, refine, degas, and remove slag to obtain a copper alloy melt. The copper alloy powder with a particle size D 50 = 14.7 μm is obtained by spray method. Place 998 copper alloy powder and 2 g of surface-modified carbon nanotubes (single-atom copper-modified carbon nanotubes customized by Beijing Graphene Technology Research Institute Co., Ltd.) in a high-speed stirring kettle, and mix at a high speed of 600 rpm for 1.0 h under argon protection to obtain the mixed alloy powder.

[0091] The difference between Comparative Example 14 and Example 1 lies in: Step 1, preparation of the copper alloy rod blank: Prepare the copper alloy powder according to the elemental formula of the mass percentage of the copper alloy powder provided in Preparation Example 1: Place high-purity cathode electrolytic copper ingots, copper-silver alloy, copper-niobium alloy, copper-indium alloy, copper-silicon alloy, copper-chromium alloy, copper-titanium alloy, copper-hafnium alloy, and copper-scandium alloy in a melting furnace at 1090 °C. After all raw materials are completely melted, refine, degas, and remove slag to obtain a copper alloy melt, and obtain copper alloy powder with a particle size D 50 = 15.2 μm. Place 998 copper alloy powder and 2 g of un-surface-modified carbon nanotubes (industrial multi-walled carbon nanotubes TNNF-6, Chengdu Organic Chemistry Co., Ltd., Chinese Academy of Sciences) in a high-speed stirring kettle, and mix at a high speed of 600 rpm for 1.0 h under argon protection to obtain a mixed alloy powder.

[0092] The difference between Comparative Example 15 and Example 1 lies in: Step 1, preparation of the copper alloy rod blank: Prepare the copper alloy powder according to the elemental formula of the mass percentage of the copper alloy powder provided in Preparation Example 1: Place high-purity cathode electrolytic copper ingots, copper-silver alloy, copper-niobium alloy, copper-indium alloy, copper-silicon alloy, copper-chromium alloy, copper-titanium alloy, copper-hafnium alloy, and copper-scandium alloy in a melting furnace at 1090 °C. After all raw materials are completely melted, refine, degas, and remove slag to obtain a copper alloy melt, and obtain copper alloy powder with a particle size D 50 = 14.7 μm. Place 999.5 copper alloy powder and 0.5 g of surface-modified carbon nanotubes (single-atom copper-modified carbon nanotubes customized by Beijing Graphene Technology Research Institute Co., Ltd.) in a high-speed stirring kettle, and mix at a high speed of 600 rpm for 1.0 h under argon protection to obtain a mixed alloy powder.

[0093] The difference between Comparative Example 16 and Example 1 lies in: Step 1, preparation of the copper alloy rod blank: Prepare the copper alloy powder according to the elemental formula of the mass percentage of the copper alloy powder provided in Preparation Example 1: Place high-purity cathode electrolytic copper ingots, copper-silver alloy, copper-niobium alloy, copper-indium alloy, copper-silicon alloy, copper-chromium alloy, copper-titanium alloy, copper-hafnium alloy, and copper-scandium alloy in a melting furnace at 1090 °C. After all raw materials are completely melted, refine, degas, and remove slag to obtain a copper alloy melt, and obtain copper alloy powder with a particle size D 50 = 14.6 μm. Place 998 copper alloy powder and 12 g of surface-modified carbon nanotubes (single-atom copper-modified carbon nanotubes customized by Beijing Graphene Technology Research Institute Co., Ltd.) in a high-speed stirring kettle, and mix at a high speed of 600 rpm for 1.0 h under argon protection to obtain a mixed alloy powder.

[0094] Performance detection test: 1. Mechanical property test: Use the HH11013YZUFY universal tensile testing machine to measure the tensile strength and elongation at break of the copper alloy rod blank according to GB / T228.1-2010. 2. Conductivity test: Use the QJ-36 digital bridge and supporting bracket to test the volume resistivity (conductivity) of the single wire, and conduct the test according to GB / T3048.7-2008. 3. Bending property test: Use the TH-8506 wire bending testing machine to conduct repeated bending tests on the finished cable. Conduct the test according to EN50396:2005+A1:2011(E). The cable transmission performance requirements refer to IEC61156-5:2020. The relevant test conditions and requirements refer to those issued by the PI Association. The repeated bending radius is 7 times the outer diameter of the cable, and the hanging weight is 300g. The transmission performance is tested online when the repeated bending test reaches the set number of times. The number of bending times of the last pass of the transmission performance is used as the test result. When the number of bending times of the specimen ≥ 3.5 million times, it is recorded as qualified, and when the number of bending times < 3.5 million times, it is recorded as unqualified.

[0095] Table 4: Physical property test table of the copper alloy rod blank in Examples 1-16 and the table of the bending resistance performance of the cable made of the stranded ultra-fine copper stranded conductor wire prepared from the copper alloy rod blank

[0096]

[0097] Table 5: Physical property test table of the copper alloy rod blank in Comparative Examples 1-16 and the table of the bending resistance performance of the cable made of the stranded ultra-fine copper stranded conductor wire prepared from the copper alloy rod blank

[0098]

[0099] Combined with Examples 1-7 and Comparative Examples 8-13 and Tables 4-5, it can be seen that the copper alloy prepared with the copper alloy formula provided in the present invention and the copper alloy rod blank prepared with single-atom copper-modified carbon nanotubes have excellent conductivity, mechanical strength, and high flexural resistance performance.

[0100] Combined with Example 1, Examples 8-11 and Comparative Example 14 and Tables 4-5, it can be seen that single-atom copper-modified carbon nanotubes can be evenly dispersed in the copper alloy matrix, effectively improving the conductivity, mechanical strength, and high flexural resistance performance of the copper alloy rod blank.

[0101] Combined with Example 1, Examples 8-11 and Comparative Examples 15-16 and Tables 4-5, it can be seen that the addition amount of single-atom copper-modified carbon nanotubes is preferably controlled at 0.2-1.0 wt%, and the preferred range is 0.5-0.7 wt%.

[0102] Combining Example 1 with Examples 12 - 16 and referring to Table 4, it can be seen that for the solution treatment parameters: heating to 980 - 1060 °C and holding for 15 - 45 min, and the aging treatment parameters: heating to 420 - 480 °C and holding for 120 - 160 min, the prepared copper alloy rod blanks have excellent electrical conductivity, mechanical strength, and high flexural resistance performance.

[0103] In summary, in the present invention, surface single - atom copper modification of carbon nanotubes improves the compatibility between carbon nanotubes and the copper alloy matrix. The carbon nanotubes are uniformly dispersed in the copper alloy melt under melting conditions, improving the electrical conductivity, mechanical strength, and flexural resistance performance of the copper alloy rod blanks. The copper alloy rod blanks are comparable to the high - strength and high - conductivity special copper conductors imported from abroad. Combining with the multiple wire drawing and multiple intermediate annealing treatments + final annealing provided in the present invention can effectively avoid wire breakage problems during wire drawing. Finally, multi - strand stranding can produce an ultra - fine copper stranded conductor wire with high electrical conductivity, high strength, and high flexural resistance performance, meeting the requirements of high - voltage cables for new energy vehicles.

[0104] This specific embodiment is only an explanation of the present invention and is not a limitation thereof. After reading this specification, those skilled in the art can make modifications to this embodiment without creative contributions as needed, but as long as they are within the scope of the claims of the present invention, they are protected by the patent law.

Claims

1. A preparation process for ultra-fine copper conductors used in new energy vehicles, characterized in that: It includes the following steps: Step 1, preparation of copper alloy rod blanks: Mix copper alloy powder and surface-modified carbon nanotubes evenly to obtain a mixed alloy powder, and the content of surface-modified carbon nanotubes in the mixed alloy powder is 0.2 - 1.0 wt%; The elements in the copper alloy powder by mass percentage are as follows: 0.05% - 0.15% of Ag, 0.05% - 0.50% of Nb, 0.01% - 0.10% of In, 0.02% - 0.08% of Si, 0.30% - 0.80% of Cr, 0.003% - 0.008% of Ti, 0.002% - 0.06% of Hf, 0.004% - 0.016% of Sc, the total content of inevitable impurities < 0.15%, and the balance is Cu; Step 2, melt-cast the mixed alloy powder in Step 2 into a copper alloy rod blank with a diameter of 8 - 12 mm, and subject the obtained copper alloy rod blank to solution treatment and aging treatment to obtain a formed copper alloy rod; Step 3, perform the first wire drawing treatment and the first intermediate annealing treatment on the formed copper alloy rod with a diameter of 8 - 12 mm in Step 3 to obtain a copper alloy thick wire with a diameter of 3 - 6 mm; Step 4, perform the second wire drawing treatment and the second intermediate annealing treatment on the copper alloy thick wire with a diameter of 3 - 6 mm to obtain a primary copper alloy fine wire with a diameter of 0.3 - 0.6 mm; Step 5, perform the third wire drawing treatment and the third intermediate annealing treatment on the primary copper alloy fine wire with a diameter of 0.3 - 0.6 mm to obtain a semi-finished copper alloy ultra-fine single-strand wire with a diameter of 0.80 - 1.08 mm; Step 6, perform the final annealing treatment on the semi-finished copper alloy ultra-fine wire to obtain a finished copper alloy ultra-fine single-strand wire, and multi-strand stranding using the finished copper alloy ultra-fine single-strand wire can produce an ultra-fine copper stranded conductor wire.

2. The preparation process of the ultra-fine copper conductor for a new energy vehicle according to claim 1, characterized in that: The content of surface-modified carbon nanotubes in the mixed alloy powder is 0.5 - 0.6 wt%.

3. The preparation process of the ultra-fine copper conductor for a new energy vehicle according to claim 2, characterized in that: The surface-modified carbon nanotubes are single-atom copper-modified carbon nanotubes, the single-atom copper loading rate is 5 - 10 wt%, the diameter of the carbon nanotubes is 5 - 40 nm, the length is 0.5 - 20 nm, and the hydroxyl content is 2 - 3 wt%.

4. The preparation process of the ultra-fine copper conductor for a new energy vehicle according to claim 1, characterized in that: The solution treatment parameters in Step 2: Heat up to 980 - 1060 °C and hold for 15 - 45 min.

5. The preparation process of the ultra-fine copper conductor for a new energy vehicle according to claim 4, characterized in that: The solution treatment parameters in Step 2: Heat up to 1020 - 1040 °C and hold for 25 - 30 min.

6. The preparation process of ultrafine copper conductors for new energy vehicles according to claim 5 is characterized in that: The aging treatment parameters in Step 2: Heat up to 420 - 480 °C and hold for 120 - 160 min.

7. The preparation process of ultra-fine copper conductors for new energy vehicles according to claim 6, characterized in that: In the first wire drawing treatment in Step 3, the angle α of the extrusion die used is 25 - 30°, and the processing deformation rate is 8 ± 0.5%; the parameters of the first intermediate annealing treatment are to heat up to 840 - 860 °C and hold for 15 - 30 min.

8. The preparation process of the ultra-fine copper conductor for a new energy vehicle according to claim 7, characterized in that: In the second wire drawing treatment in Step 4, the angle α of the extrusion die used is 25 - 30°, and the processing deformation rate is 5 ± 0.5%; the parameters of the second intermediate annealing treatment are to heat up to 840 - 860 °C and hold for 15 - 30 min.

9. The preparation process of the ultra-fine copper conductor for a new energy vehicle according to claim 8, characterized in that: In the third wire drawing process of Step 5, the angle α of the extrusion die used is 25 - 30°, and the processing deformation rate is 2 ± 0.5%; the parameters of the third intermediate annealing treatment are heating to 840 - 860°C and holding for 15 - 30 minutes.

10. The preparation process of the ultra-fine copper conductor for a new energy vehicle according to claim 9, characterized in that: Parameters of the final annealing treatment: Heat to 900 - 960°C and hold for 0.4 - 0.6 s.

Images