High-conductivity gradient copper alloy slot line and preparation method thereof

Abstract

The invention discloses a high-conductivity gradient copper alloy slot line and a preparation method thereof, and relates to the technical field of copper alloy materials, and the high-conductivity gradient copper alloy slot line comprises the following components in percentage by mass: 0.3%-0.6% of Ag, 0.01%-0.1% of rare earth elements, 0.05%-0.15% of Co, 0.02%-0.12% of Ni, 0.01%-0.03% of Ba, 0.05%-0.8% of Nb, 0.01%-0.05% of Ta, 0.003%-0.007% of Re, 0.08%-0.2% of Hf, 0.2%-0.6% of Mg, 0.01%-0.05% of carbon nanotubes, 0.01%-0.03% of fullerene and the balance of Cu and other inevitable impurities. The rare earth element is formed by mixing Ce, La and Y according to the mass ratio of (1-2): 1: (0.8-1.2). The slot line is excellent in mechanical property, fatigue resistance, corrosion resistance and conductivity.

Description

Technical Field

[0001] The present invention relates to the technical field of copper alloy materials, and in particular to a high-conductivity gradient copper alloy slot line and a preparation method thereof. Background Art

[0002] Copper alloy trough wire is a copper alloy material with a specific shape (usually a trough). It is generally made by melting and processing pure copper and other metal elements such as zinc, tin, lead, aluminum, and nickel through a specific process. Due to its excellent electrical and thermal conductivity, high strength and hardness, excellent corrosion resistance, and processability, it is widely used in power transmission, electrical equipment, electronic information, machinery manufacturing, and architectural decoration. With the rapid development of modern high-end manufacturing, the performance requirements of copper alloy trough wire have reached new heights.

[0003] Traditional copper alloy slotted wires utilize a static composition design, which, while meeting basic performance requirements, presents a significant problem. However, under high-frequency signal transmission and high current density conditions, the skin effect causes a significant surge in surface resistance, making it difficult to meet the low-loss, high-speed transmission requirements of next-generation electronic devices. To improve the conductivity of copper alloy slotted wires, trace alloying elements such as silver and magnesium are often added. However, improper selection of the type and amount of alloying elements can lead to technical drawbacks such as limited mechanical properties and fatigue resistance, and further improvements in corrosion resistance and electrical conductivity.

[0004] Chinese invention patent application publication number CN119811777A discloses a method for preparing slotted wire for superconducting wire, comprising: drawing copper rods into copper flat wires; soaking the copper flat wires in flux, then washing and air-drying them to obtain prefabricated copper flat wires; combining multiple prefabricated copper flat wires according to the cross-sectional structure of the superconducting wire; welding the combined prefabricated copper flat wires through induction heating in a welding mold to obtain copper slotted wires; water-cooling, washing, and drying the copper slotted wires to obtain surface-cleaned copper slotted wires; and screening the copper slotted wires using a laser caliper and eddy current flaw detection equipment to obtain finished copper slotted wires. This invention achieves integrated structural slotted wire formation by welding copper flat wires, improving production efficiency. By designing molds with different structures for welding and finishing, the surface quality of the copper slotted wires is improved, resulting in high-precision slotted wires with complex structures. Drawing speed is high, facilitating large-scale production of copper slotted wires. However, it only processes the slot wire from the perspective of preparation technology, without improving the material formula, so that the mechanical properties, fatigue resistance, corrosion resistance and electrical conductivity of the products made by this method still need to be further improved.

[0005] It can be seen that the development of a copper alloy slot line with excellent mechanical properties, fatigue resistance, corrosion resistance and electrical conductivity and its preparation method meets market demand, has broad market value and application prospects, and is of great significance to promoting the development of the copper alloy slot line field. Summary of the Invention

[0006] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a high conductivity gradient copper alloy slot wire with excellent mechanical properties, fatigue resistance, corrosion resistance and electrical conductivity and a preparation method thereof.

[0007] To achieve the above-mentioned object, the technical solution adopted by the present invention is: a high-conductivity gradient copper alloy slot wire, which comprises, by mass percentage, the following components: Ag 0.3-0.6%, rare earth elements 0.01-0.1%, Co 0.05-0.15%, Ni 0.02-0.12%, Ba 0.01-0.03%, Nb 0.05-0.8%, Ta 0.01-0.05%, Re 0.003-0.007%, Hf 0.08-0.2%, Mg 0.2-0.6%, carbon nanotubes 0.01-0.05%, fullerenes 0.01-0.03%, and the balance being Cu and other inevitable impurities.

[0008] Preferably, the rare earth elements are Ce, La, and Y mixed in a mass ratio of (1-2):1:(0.8-1.2).

[0009] Preferably, the carbon nanotubes are multi-walled carbon nanotubes with an outer diameter of 6-13 nm and a length of 2.5-20 μm, with product number 698849, provided by Merck Chemicals.

[0010] Preferably, the fullerene is fullerene-C 60 , with an average diameter of 0.7 nm, product number 379646, provided by Merck Chemicals.

[0011] Another object of the present invention is to provide a method for preparing the high conductivity gradient copper alloy slot wire, comprising the following steps:

[0012] Step S1, pretreatment of carbon nanotubes and fullerenes: The carbon nanotubes and fullerenes are ultrasonically dispersed in a 3-5% nitric acid solution for 25-35 minutes to remove surface impurities; then, surface modification is performed using a silane coupling agent KH-550, and the mixture is reacted in an 80°C water bath for 2-4 hours. After drying, surface-activated carbon nanotubes and fullerenes are obtained;

[0013] Step S2, alloy smelting and nanocomposite: electrolytic copper, Ag-Cu master alloy, rare earth element-Cu master alloy, Co-Cu master alloy, Ni-Cu master alloy, Ba-Cu master alloy, Nb-Cu master alloy, Ta-Cu master alloy, Re-Cu master alloy, Hf-Cu master alloy, and Mg-Cu master alloy are added as raw materials into a vacuum induction melting furnace for smelting; surface-activated carbon nanotubes and fullerenes are added into the melt in three portions with an interval of 5 minutes between each addition, while electromagnetic stirring is turned on for uniform stirring to obtain an alloy liquid;

[0014] Step S3, gradient solidification and texture control: pouring the alloy liquid into a directional solidification mold with a temperature gradient, performing directional solidification at a cooling rate of 10°C / min to form an ingot with a columnar crystal orientation; applying a pulsed magnetic field during the solidification process to initially form a composition gradient;

[0015] Step S4, hot isostatic pressing: placing the ingot in a hot isostatic pressing device for hot isostatic pressing to obtain a billet;

[0016] Step S5, composite processing and gradient strengthening: the billet is rolled using a cumulative rolling process, and during the rolling process, a 60nm thick silver-copper-indium gradient alloy layer is deposited on the surface using ion beam sputtering technology; then a cryogenic treatment is performed to obtain a primary groove line product;

[0017] Step S6, laser-assisted processing: using a high-power pulsed laser to scan the surface of the initial groove line product;

[0018] Step S7, heat treatment: placing the copper alloy slot wire in a high-purity argon protective atmosphere furnace for annealing treatment to obtain a high-conductivity gradient copper alloy slot wire.

[0019] Preferably, the mass of the silane coupling agent KH-550 in step S1 is 0.8-1.5% of the total mass of the carbon nanotubes and fullerenes.

[0020] Preferably, the melting temperature in step S2 is 1200-1220°C and the vacuum degree is 1×10 -5 Pa.

[0021] Preferably, the frequency of the electromagnetic stirring in step S2 is 20-25 Hz, and the intensity is 0.5-0.6 T.

[0022] Preferably, the bottom temperature of the directional solidification mold with a temperature gradient in step S3 is 275-285°C, and the top temperature is 515-525°C.

[0023] Preferably, the magnetic induction intensity of the pulsed magnetic field in step S3 is 0.8-0.9 T, the frequency is 10-12 Hz, and the pulse width is 500-550 ms.

[0024] Preferably, the hot isostatic pressing in step S4 is performed at a pressure of 100-110 MPa, a temperature of 890-910° C., and a time of 5-7 h.

[0025] Preferably, the rolling temperature in step S5 is 300-320° C., and the rolling is performed in 8 passes, with a deformation of 20% in each pass.

[0026] Preferably, the mass ratio of surface silver, copper and indium in the silver-copper-indium gradient alloy layer in step S5 is 85:10:5; the silver content in the alloy layer gradually decreases from 85% on the surface to the groove base to a silver content close to the matrix at the junction with the matrix; the indium element content gradually decreases from 5% on the surface to below 1% at a distance of about 20 nm from the surface, and the copper element content gradually increases from 10% on the surface to the copper content of the matrix.

[0027] Preferably, the temperature of the cryogenic treatment in step S5 is -195°C to -200°C, and the time is 10-12 hours.

[0028] Preferably, the wavelength of the high-power pulse laser in step S6 is 1064 nm, the pulse width is 100 ns, the frequency is 10 Hz, and the power density is 5×10 8 W / cm 2 .

[0029] Preferably, the scanning speed of the scanning process in step S6 is 50 mm / s, and the spot diameter is 1 mm.

[0030] Preferably, the annealing treatment in step S7 adopts a three-stage annealing process, first keeping the temperature at 410-430°C for 1-1.2 hours, then heating to 560-590°C for 0.5-0.7 hours, and finally cooling to 470-490°C for 0.8-0.9 hours.

[0031] Due to the application of the above technical solution, the present invention has the following beneficial effects:

[0032] (1) The method for preparing high-conductivity gradient copper alloy slot wire disclosed in the present invention has simple process, convenient operation and control, high preparation efficiency and finished product qualification rate, is suitable for continuous large-scale production, and has high promotion and application value.

[0033] (2) The high-conductivity gradient copper alloy slotted wire disclosed in the present invention comprises, by mass percentage, the following components: Ag 0.3-0.6%, rare earth elements 0.01-0.1%, Co 0.05-0.15%, Ni 0.02-0.12%, Ba 0.01-0.03%, Nb 0.05-0.8%, Ta 0.01-0.05%, Re 0.003-0.007%, Hf 0.08-0.2%, Mg 0.2-0.6%, carbon nanotubes 0.01-0.05%, fullerene 0.01-0.03%, with the balance being Cu and other unavoidable impurities. By rationally selecting the types and amounts of the components, the components can cooperate with each other to effectively improve the mechanical properties, fatigue resistance, corrosion resistance, and electrical conductivity of the slotted wire. By adding carbon nanotubes and fullerenes into the copper alloy system and precisely controlling their dosage and performing surface modification treatment, the problem of uniform dispersion and effective utilization of nanomaterials in copper alloys is solved. With their high specific surface area and excellent conductivity, they effectively reduce electron scattering and significantly improve the surface conductivity of the alloy.

[0034] (3) The high conductivity gradient copper alloy slot line disclosed in the present invention adopts gradient solidification and pulsed magnetic field control to promote dynamic segregation of alloy elements with carbon nanotubes and fullerenes, and starts to build a composition gradient from the solidification stage; it adopts laser-assisted surface treatment, introduces high-power pulsed laser processing technology, and utilizes the rapid heating and cooling characteristics of laser to form a nano-scale recrystallization layer on the surface, which not only significantly improves the surface conductivity, but also enhances the surface hardness, thereby effectively improving the surface properties of the material.

[0035] (4) The high-conductivity gradient copper alloy slotted wire disclosed in the present invention utilizes a combination of cumulative rolling, ion beam sputtering, and cryogenic treatment processes. This utilizes differences in thermal expansion coefficients to induce nanophase dispersion and precipitation, achieving deep gradient strengthening from the surface to the core. This significantly improves the mechanical properties, fatigue resistance, corrosion resistance, and electrical conductivity of the resulting slotted wire. The use of a three-stage annealing process can effectively improve production efficiency and enhance the electrical conductivity and mechanical properties of the slotted wire. DETAILED DESCRIPTION

[0036] The following description is intended to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are merely examples, and those skilled in the art may conceive of other obvious variations.

[0037] Example 1

[0038] A high-conductivity gradient copper alloy slot wire comprises, by mass percentage, 0.3% Ag, 0.01% rare earth elements, 0.05% Co, 0.02% Ni, 0.01% Ba, 0.05% Nb, 0.01% Ta, 0.003% Re, 0.08% Hf, 0.2% Mg, 0.01% carbon nanotubes, 0.01% fullerene, and the balance being Cu and other unavoidable impurities.

[0039] The rare earth elements are Ce, La, and Y mixed in a mass ratio of 1:1:0.8; the carbon nanotubes are multi-walled carbon nanotubes with an outer diameter of 6-13 nm and a length of 2.5-20 μm, with item number 698849, provided by Merck Chemicals; the fullerene is fullerene-C 60 , with an average diameter of 0.7 nm, product number 379646, provided by Merck Chemicals.

[0040] A method for preparing the high conductivity gradient copper alloy slot line comprises the following steps:

[0041] Step S1, pretreatment of carbon nanotubes and fullerenes: The carbon nanotubes and fullerenes were ultrasonically dispersed in a 3% nitric acid solution for 25 minutes to remove surface impurities; then, the surface was modified using a silane coupling agent KH-550, reacted in an 80°C water bath for 2 hours, and dried to obtain surface-activated carbon nanotubes and fullerenes;

[0042] Step S2, alloy smelting and nanocomposite: electrolytic copper, Ag-Cu master alloy, rare earth element-Cu master alloy, Co-Cu master alloy, Ni-Cu master alloy, Ba-Cu master alloy, Nb-Cu master alloy, Ta-Cu master alloy, Re-Cu master alloy, Hf-Cu master alloy, and Mg-Cu master alloy are added as raw materials into a vacuum induction melting furnace for smelting; surface-activated carbon nanotubes and fullerenes are added into the melt in three portions with an interval of 5 minutes between each addition, while electromagnetic stirring is turned on for uniform stirring to obtain an alloy liquid;

[0043] Step S3, gradient solidification and texture control: pouring the alloy liquid into a directional solidification mold with a temperature gradient, performing directional solidification at a cooling rate of 10°C / min to form an ingot with a columnar crystal orientation; applying a pulsed magnetic field during the solidification process to initially form a composition gradient;

[0044] Step S4, hot isostatic pressing: placing the ingot in a hot isostatic pressing device for hot isostatic pressing to obtain a billet;

[0045] Step S5, composite processing and gradient strengthening: the billet is rolled using a cumulative rolling process, and during the rolling process, a 60nm thick silver-copper-indium gradient alloy layer is deposited on the surface using ion beam sputtering technology; then a cryogenic treatment is performed to obtain a primary groove line product;

[0046] Step S6, laser-assisted processing: using a high-power pulsed laser to scan the surface of the initial groove line product;

[0047] Step S7, heat treatment: placing the copper alloy slot wire in a high-purity argon protective atmosphere furnace for annealing treatment to obtain a high-conductivity gradient copper alloy slot wire.

[0048] The mass of the silane coupling agent KH-550 in step S1 is 0.8% of the total mass of the carbon nanotubes and fullerenes; the melting temperature in step S2 is 1200°C and the vacuum degree is 1×10 -5 Pa; the frequency of the electromagnetic stirring in step S2 is 20 Hz and the intensity is 0.5 T; the bottom temperature of the directional solidification mold with a temperature gradient in step S3 is 275 ° C, and the top temperature is 515 ° C; the magnetic induction intensity of the pulsed magnetic field in step S3 is 0.8 T, the frequency is 10 Hz, and the pulse width is 500 ms.

[0049] The hot isostatic pressing in step S4 is performed at a pressure of 100 MPa, a temperature of 890° C., and a time of 5 h. The rolling in step S5 is performed at a temperature of 300° C., with 8 rolling passes and a deformation of 20% per pass. The mass ratio of surface silver, copper, and indium in the silver-copper-indium gradient alloy layer in step S5 is 85:10:5. The silver content in the alloy layer decreases gradually from 85% on the surface to the groove base, approaching the silver content of the matrix at the junction with the matrix. The indium content gradually decreases from 5% on the surface to below 1% at a distance of about 20 nm from the surface, and the copper content gradually increases from 10% on the surface to the copper content of the matrix.

[0050] The temperature of the cryogenic treatment in step S5 is -195°C and the time is 10 hours; the wavelength of the high-power pulse laser in step S6 is 1064 nm, the pulse width is 100 ns, the frequency is 10 Hz, and the power density is 5×10 8 W / cm 2 ; The scanning speed of the scanning process described in step S6 is 50mm / s, and the spot diameter is 1mm; the annealing process described in step S7 adopts a three-stage annealing process, first keeping it at 410℃ for 1 hour, then heating it to 560℃ and keeping it for 0.5 hour, and finally cooling it to 470℃ and keeping it for 0.8 hour.

[0051] Example 2

[0052] A high-conductivity gradient copper alloy slot wire comprises, by mass percentage, 0.4% Ag, 0.03% rare earth elements, 0.08% Co, 0.05% Ni, 0.015% Ba, 0.2% Nb, 0.02% Ta, 0.004% Re, 0.12% Hf, 0.3% Mg, 0.02% carbon nanotubes, 0.015% fullerene, and the balance being Cu and other unavoidable impurities.

[0053] The rare earth elements are Ce, La, and Y mixed in a mass ratio of 1.3:1:0.9; the carbon nanotubes are multi-walled carbon nanotubes with an outer diameter of 6-13 nm and a length of 2.5-20 μm, with item number 698849, provided by Merck Chemicals; the fullerene is fullerene-C 60 , with an average diameter of 0.7 nm, product number 379646, provided by Merck Chemicals.

[0054] A method for preparing the high conductivity gradient copper alloy slot line comprises the following steps:

[0055] Step S1, pretreatment of carbon nanotubes and fullerenes: The carbon nanotubes and fullerenes were ultrasonically dispersed in a 3.5% nitric acid solution for 28 minutes to remove surface impurities; then, the surfaces were modified using a silane coupling agent KH-550, reacted in an 80°C water bath for 2.5 hours, and dried to obtain surface-activated carbon nanotubes and fullerenes;

[0056] Step S2, alloy smelting and nanocomposite: electrolytic copper, Ag-Cu master alloy, rare earth element-Cu master alloy, Co-Cu master alloy, Ni-Cu master alloy, Ba-Cu master alloy, Nb-Cu master alloy, Ta-Cu master alloy, Re-Cu master alloy, Hf-Cu master alloy, and Mg-Cu master alloy are added as raw materials into a vacuum induction melting furnace for smelting; surface-activated carbon nanotubes and fullerenes are added into the melt in three portions with an interval of 5 minutes between each addition, while electromagnetic stirring is turned on for uniform stirring to obtain an alloy liquid;

[0057] Step S3, gradient solidification and texture control: pouring the alloy liquid into a directional solidification mold with a temperature gradient, performing directional solidification at a cooling rate of 10°C / min to form an ingot with a columnar crystal orientation; applying a pulsed magnetic field during the solidification process to initially form a composition gradient;

[0058] Step S4, hot isostatic pressing: placing the ingot in a hot isostatic pressing device for hot isostatic pressing to obtain a billet;

[0059] Step S5, composite processing and gradient strengthening: the billet is rolled using a cumulative rolling process, and during the rolling process, a 60nm thick silver-copper-indium gradient alloy layer is deposited on the surface using ion beam sputtering technology; then a cryogenic treatment is performed to obtain a primary groove line product;

[0060] Step S6, laser-assisted processing: using a high-power pulsed laser to scan the surface of the initial groove line product;

[0061] Step S7, heat treatment: placing the copper alloy slot wire in a high-purity argon protective atmosphere furnace for annealing treatment to obtain a high-conductivity gradient copper alloy slot wire.

[0062] The mass of the silane coupling agent KH-550 in step S1 is 1% of the total mass of the carbon nanotubes and fullerenes; the melting temperature in step S2 is 1205°C and the vacuum degree is 1×10 -5 Pa; the frequency of the electromagnetic stirring in step S2 is 22 Hz and the intensity is 0.52 T; the bottom temperature of the directional solidification mold with a temperature gradient in step S3 is 278 ° C, and the top temperature is 518 ° C; the magnetic induction intensity of the pulsed magnetic field in step S3 is 0.83 T, the frequency is 10.5 Hz, and the pulse width is 520 ms.

[0063] The hot isostatic pressing in step S4 is performed at a pressure of 103 MPa, a temperature of 895° C., and a time of 5.5 h; the rolling temperature in step S5 is 305° C., and the rolling is performed in 8 passes with a deformation of 20% per pass; the mass ratio of surface silver, copper, and indium in the silver-copper-indium gradient alloy layer in step S5 is 85:10:5; the silver content in the alloy layer decreases gradually from 85% on the surface to the base of the groove line to a silver content close to that of the matrix at the junction with the matrix; the indium content gradually decreases from 5% on the surface to below 1% at a distance of about 20 nm from the surface, and the copper content gradually increases from 10% on the surface to the copper content of the matrix.

[0064] The temperature of the cryogenic treatment in step S5 is -197 ° C, and the time is 10.5 h; the wavelength of the high-power pulse laser in step S6 is 1064 nm, the pulse width is 100 ns, the frequency is 10 Hz, and the power density is 5 × 10 8 W / cm 2 ; The scanning speed of the scanning process described in step S6 is 50mm / s, and the spot diameter is 1mm; the annealing process described in step S7 adopts a three-stage annealing process, first keeping it at 415℃ for 1.1 hours, then heating it to 570℃ and keeping it for 0.55 hours, and finally cooling it to 475℃ and keeping it for 0.83 hours.

[0065] Example 3

[0066] A high-conductivity gradient copper alloy slot wire comprises, by mass percentage, 0.45% Ag, 0.06% rare earth elements, 0.1% Co, 0.08% Ni, 0.02% Ba, 0.5% Nb, 0.035% Ta, 0.005% Re, 0.15% Hf, 0.4% Mg, 0.035% carbon nanotubes, 0.02% fullerene, and the balance being Cu and other unavoidable impurities.

[0067] The rare earth elements are Ce, La, and Y mixed in a mass ratio of 1.5:1:1; the carbon nanotubes are multi-walled carbon nanotubes with an outer diameter of 6-13 nm and a length of 2.5-20 μm, with item number 698849, provided by Merck Chemicals; the fullerene is fullerene-C 60 , with an average diameter of 0.7 nm, product number 379646, provided by Merck Chemicals.

[0068] A method for preparing the high conductivity gradient copper alloy slot line comprises the following steps:

[0069] Step S1, pretreatment of carbon nanotubes and fullerenes: The carbon nanotubes and fullerenes were ultrasonically dispersed in a 4% nitric acid solution for 30 minutes to remove surface impurities; then, the surface was modified using a silane coupling agent KH-550, reacted in an 80°C water bath for 3 hours, and dried to obtain surface-activated carbon nanotubes and fullerenes;

[0070] Step S2, alloy smelting and nanocomposite: electrolytic copper, Ag-Cu master alloy, rare earth element-Cu master alloy, Co-Cu master alloy, Ni-Cu master alloy, Ba-Cu master alloy, Nb-Cu master alloy, Ta-Cu master alloy, Re-Cu master alloy, Hf-Cu master alloy, and Mg-Cu master alloy are added as raw materials into a vacuum induction melting furnace for smelting; surface-activated carbon nanotubes and fullerenes are added into the melt in three portions with an interval of 5 minutes between each addition, while electromagnetic stirring is turned on for uniform stirring to obtain an alloy liquid;

[0071] Step S3, gradient solidification and texture control: pouring the alloy liquid into a directional solidification mold with a temperature gradient, performing directional solidification at a cooling rate of 10°C / min to form an ingot with a columnar crystal orientation; applying a pulsed magnetic field during the solidification process to initially form a composition gradient;

[0072] Step S4, hot isostatic pressing: placing the ingot in a hot isostatic pressing device for hot isostatic pressing to obtain a billet;

[0073] Step S5, composite processing and gradient strengthening: the billet is rolled using a cumulative rolling process, and during the rolling process, a 60nm thick silver-copper-indium gradient alloy layer is deposited on the surface using ion beam sputtering technology; then a cryogenic treatment is performed to obtain a primary groove line product;

[0074] Step S6, laser-assisted processing: using a high-power pulsed laser to scan the surface of the initial groove line product;

[0075] Step S7, heat treatment: placing the copper alloy slot wire in a high-purity argon protective atmosphere furnace for annealing treatment to obtain a high-conductivity gradient copper alloy slot wire.

[0076] The mass of the silane coupling agent KH-550 in step S1 is 1.3% of the total mass of the carbon nanotubes and fullerenes; the melting temperature in step S2 is 1210°C and the vacuum degree is 1×10 -5 Pa; the frequency of the electromagnetic stirring in step S2 is 23 Hz, and the intensity is 0.55 T; the bottom temperature of the directional solidification mold with a temperature gradient in step S3 is 280 ° C, and the top temperature is 520 ° C; the magnetic induction intensity of the pulsed magnetic field in step S3 is 0.85 T, the frequency is 11 Hz, and the pulse width is 530 ms; the pressure of the hot isostatic pressing in step S4 is 105 MPa, the temperature is 900 ° C, and the time is 6 h; the rolling temperature in step S5 is 310 ° C, and the rolling is 8 passes, with a deformation of 20% in each pass.

[0077] The mass ratio of silver, copper, and indium on the surface of the silver-copper-indium gradient alloy layer in step S5 is 85:10:5; the silver content in the alloy layer decreases gradually from 85% on the surface to the base of the groove line to a silver content close to the base at the junction with the base; the indium content gradually decreases from 5% on the surface to below 1% at a distance of about 20 nm from the surface, and the copper content gradually increases from 10% on the surface to the copper content of the base; the temperature of the deep cryogenic treatment in step S5 is -198°C and the time is 11 hours; the wavelength of the high-power pulsed laser in step S6 is 1064 nm, the pulse width is 100 ns, the frequency is 10 Hz, and the power density is 5×10 8 W / cm 2 ; The scanning speed of the scanning process described in step S6 is 50mm / s, and the spot diameter is 1mm; the annealing process described in step S7 adopts a three-stage annealing process, first keeping it at 420℃ for 1.1 hours, then heating it to 575℃ and keeping it for 0.6 hours, and finally cooling it to 480℃ and keeping it for 0.85 hours.

[0078] Example 4

[0079] A high-conductivity gradient copper alloy slot wire comprises, by mass percentage, 0.55% Ag, 0.09% rare earth elements, 0.13% Co, 0.1% Ni, 0.025% Ba, 0.7% Nb, 0.04% Ta, 0.006% Re, 0.18% Hf, 0.55% Mg, 0.04% carbon nanotubes, 0.025% fullerene, and the balance being Cu and other unavoidable impurities.

[0080] The rare earth elements are Ce, La, and Y mixed in a mass ratio of 1.8:1:1.1; the carbon nanotubes are multi-walled carbon nanotubes with an outer diameter of 6-13 nm and a length of 2.5-20 μm, with item number 698849, provided by Merck Chemicals; the fullerene is fullerene-C 60 , with an average diameter of 0.7 nm, product number 379646, provided by Merck Chemicals.

[0081] A method for preparing the high conductivity gradient copper alloy slot line comprises the following steps:

[0082] Step S1, pretreatment of carbon nanotubes and fullerenes: The carbon nanotubes and fullerenes were ultrasonically dispersed in a 4.5% nitric acid solution for 33 minutes to remove surface impurities; then, the surfaces were modified using a silane coupling agent KH-550, reacted in an 80°C water bath for 3.5 hours, and dried to obtain surface-activated carbon nanotubes and fullerenes;

[0083] Step S2, alloy smelting and nanocomposite: electrolytic copper, Ag-Cu master alloy, rare earth element-Cu master alloy, Co-Cu master alloy, Ni-Cu master alloy, Ba-Cu master alloy, Nb-Cu master alloy, Ta-Cu master alloy, Re-Cu master alloy, Hf-Cu master alloy, and Mg-Cu master alloy are added as raw materials into a vacuum induction melting furnace for smelting; surface-activated carbon nanotubes and fullerenes are added into the melt in three portions with an interval of 5 minutes between each addition, while electromagnetic stirring is turned on for uniform stirring to obtain an alloy liquid;

[0084] Step S3, gradient solidification and texture control: pouring the alloy liquid into a directional solidification mold with a temperature gradient, performing directional solidification at a cooling rate of 10°C / min to form an ingot with a columnar crystal orientation; applying a pulsed magnetic field during the solidification process to initially form a composition gradient;

[0085] Step S4, hot isostatic pressing: placing the ingot in a hot isostatic pressing device for hot isostatic pressing to obtain a billet;

[0086] Step S5, composite processing and gradient strengthening: the billet is rolled using a cumulative rolling process, and during the rolling process, a 60nm thick silver-copper-indium gradient alloy layer is deposited on the surface using ion beam sputtering technology; then a cryogenic treatment is performed to obtain a primary groove line product;

[0087] Step S6, laser-assisted processing: using a high-power pulsed laser to scan the surface of the initial groove line product;

[0088] Step S7, heat treatment: placing the copper alloy slot wire in a high-purity argon protective atmosphere furnace for annealing treatment to obtain a high-conductivity gradient copper alloy slot wire.

[0089] The mass of the silane coupling agent KH-550 in step S1 is 1.3% of the total mass of the carbon nanotubes and fullerenes; the melting temperature in step S2 is 1215°C and the vacuum degree is 1×10 -5 Pa; the frequency of the electromagnetic stirring in step S2 is 24 Hz, and the intensity is 0.58 T; the bottom temperature of the directional solidification mold with a temperature gradient in step S3 is 283 ° C, and the top temperature is 523 ° C; the magnetic induction intensity of the pulsed magnetic field in step S3 is 0.88 T, the frequency is 11 Hz, and the pulse width is 540 ms; the pressure of the hot isostatic pressing in step S4 is 108 MPa, the temperature is 905 ° C, and the time is 6.5 h.

[0090] The rolling temperature in step S5 is 315° C., and the rolling is performed in 8 passes with a deformation of 20% per pass. The mass ratio of silver, copper, and indium on the surface of the silver-copper-indium gradient alloy layer in step S5 is 85:10:5. The silver content in the alloy layer decreases gradually from 85% on the surface to the base of the groove line to a silver content close to that of the matrix at the junction with the matrix. The indium content gradually decreases from 5% on the surface to below 1% at a distance of about 20 nm from the surface, and the copper content gradually increases from 10% on the surface to the copper content of the matrix. The temperature of the deep cryogenic treatment in step S5 is -199° C., and the time is 12 h. The wavelength of the high-power pulsed laser in step S6 is 1064 nm, the pulse width is 100 ns, the frequency is 10 Hz, and the power density is 5×10 8 W / cm 2 ; The scanning speed of the scanning process described in step S6 is 50mm / s, and the spot diameter is 1mm; the annealing process described in step S7 adopts a three-stage annealing process, first keeping it at 425℃ for 1.2 hours, then heating it to 585℃ and keeping it for 0.65 hours, and finally cooling it to 485℃ and keeping it for 0.88 hours.

[0091] Example 5

[0092] A high-conductivity gradient copper alloy slot wire comprises, by mass percentage, 0.6% Ag, 0.1% rare earth elements, 0.15% Co, 0.12% Ni, 0.03% Ba, 0.8% Nb, 0.05% Ta, 0.007% Re, 0.2% Hf, 0.6% Mg, 0.05% carbon nanotubes, 0.03% fullerene, and the balance being Cu and other unavoidable impurities.

[0093] The rare earth elements are Ce, La, and Y mixed in a mass ratio of 2:1:1.2; the carbon nanotubes are multi-walled carbon nanotubes with an outer diameter of 6-13 nm and a length of 2.5-20 μm, with item number 698849, provided by Merck Chemicals; the fullerene is fullerene-C 60 , with an average diameter of 0.7 nm, product number 379646, provided by Merck Chemicals.

[0094] A method for preparing the high conductivity gradient copper alloy slot line comprises the following steps:

[0095] Step S1, pretreatment of carbon nanotubes and fullerenes: The carbon nanotubes and fullerenes were ultrasonically dispersed in a 5% nitric acid solution for 35 minutes to remove surface impurities; then, the surfaces were modified using a silane coupling agent KH-550, reacted in an 80°C water bath for 4 hours, and dried to obtain surface-activated carbon nanotubes and fullerenes;

[0096] Step S2, alloy smelting and nanocomposite: electrolytic copper, Ag-Cu master alloy, rare earth element-Cu master alloy, Co-Cu master alloy, Ni-Cu master alloy, Ba-Cu master alloy, Nb-Cu master alloy, Ta-Cu master alloy, Re-Cu master alloy, Hf-Cu master alloy, and Mg-Cu master alloy are added as raw materials into a vacuum induction melting furnace for smelting; surface-activated carbon nanotubes and fullerenes are added into the melt in three portions with an interval of 5 minutes between each addition, while electromagnetic stirring is turned on for uniform stirring to obtain an alloy liquid;

[0097] Step S3, gradient solidification and texture control: pouring the alloy liquid into a directional solidification mold with a temperature gradient, performing directional solidification at a cooling rate of 10°C / min to form an ingot with a columnar crystal orientation; applying a pulsed magnetic field during the solidification process to initially form a composition gradient;

[0098] Step S4, hot isostatic pressing: placing the ingot in a hot isostatic pressing device for hot isostatic pressing to obtain a billet;

[0099] Step S5, composite processing and gradient strengthening: the billet is rolled using a cumulative rolling process, and during the rolling process, a 60nm thick silver-copper-indium gradient alloy layer is deposited on the surface using ion beam sputtering technology; then a cryogenic treatment is performed to obtain a primary groove line product;

[0100] Step S6, laser-assisted processing: using a high-power pulsed laser to scan the surface of the initial groove line product;

[0101] Step S7, heat treatment: placing the copper alloy slot wire in a high-purity argon protective atmosphere furnace for annealing treatment to obtain a high-conductivity gradient copper alloy slot wire.

[0102] The mass of the silane coupling agent KH-550 in step S1 is 1.5% of the total mass of the carbon nanotubes and fullerenes; the melting temperature in step S2 is 1220°C and the vacuum degree is 1×10 -5 Pa; the frequency of the electromagnetic stirring in step S2 is 25 Hz, and the intensity is 0.6 T; the bottom temperature of the directional solidification mold with a temperature gradient in step S3 is 285 ° C, and the top temperature is 525 ° C; the magnetic induction intensity of the pulsed magnetic field in step S3 is 0.9 T, the frequency is 12 Hz, and the pulse width is 550 ms; the pressure of the hot isostatic pressing in step S4 is 110 MPa, the temperature is 910 ° C, and the time is 7 h.

[0103] The rolling temperature in step S5 is 320° C., and the rolling is performed in 8 passes with a deformation of 20% per pass. The mass ratio of silver, copper, and indium on the surface of the silver-copper-indium gradient alloy layer in step S5 is 85:10:5. The silver content in the alloy layer decreases gradually from 85% on the surface to the base of the groove line to a silver content close to that of the matrix at the junction with the matrix. The indium content gradually decreases from 5% on the surface to below 1% at a distance of about 20 nm from the surface, and the copper content gradually increases from 10% on the surface to the copper content of the matrix. The temperature of the deep cryogenic treatment in step S5 is -200° C. and the time is 12 h. The wavelength of the high-power pulsed laser in step S6 is 1064 nm, the pulse width is 100 ns, the frequency is 10 Hz, and the power density is 5×10 8 W / cm 2 ; The scanning speed of the scanning process described in step S6 is 50mm / s, and the spot diameter is 1mm; the annealing process described in step S7 adopts a three-stage annealing process, first keeping it at 430℃ for 1.2 hours, then heating it to 590℃ and keeping it for 0.7 hours, and finally cooling it to 490℃ and keeping it for 0.9 hours.

[0104] Comparative Example 1

[0105] This example provides a high conductivity gradient copper alloy slot line and a preparation method thereof, which is basically the same as Example 1, except that Co, carbon nanotubes and Nb are not added, and there are no laser-assisted processing and deep cryogenic treatment steps.

[0106] Comparative Example 2

[0107] This example provides a high conductivity gradient copper alloy slot line and a preparation method thereof, which is basically the same as Example 1, except that Ta, Hf and fullerene are not added, and no pulsed magnetic field is applied during the solidification process.

[0108] In order to further illustrate the beneficial technical effects of the high conductivity gradient copper alloy slotted wires involved in various embodiments of the present invention, relevant performance tests were conducted on the high conductivity gradient copper alloy slotted wires involved in various examples. The test results are shown in Table 1. The test method is as follows:

[0109] (1) Conductivity test: Refer to GB / T 351-2019 for testing;

[0110] (2) Tensile properties: The room temperature tensile test was carried out according to GB / T 228.1-2021, with a tensile speed of 5 mm / min;

[0111] (3) Fatigue life: With reference to the fatigue test of JISZ 2273-1978, the number of repetitions until the test piece breaks when the load stress is 500 MPa is calculated; the wire diameter of the test piece is 0.5 mm; the above test is carried out on three wires in each case, and the average number of repetitions until the groove wire breaks is calculated.

[0112] (4) Corrosion performance test: A neutral salt spray test (5% NaCl solution, 35°C, continuous spraying for 120 hours) was carried out in accordance with GB / T 10125-2021, and the corrosion rate was calculated by the weight loss method.

[0113] Table 1 Performance test results of high conductivity gradient copper alloy slot line

[0114] project Surface conductivity tensile strength Fatigue life Corrosion rate unit %IACS MPa <![CDATA[×10 7 times]]> <![CDATA[g / (m 2 ·h)]]> Example 1 99.8 582 1.25 0.012 Example 2 101.2 585 1.30 0.010 Example 3 102.2 590 1.33 0.007 Example 4 103.0 592 1.35 0.006 Example 5 104.2 595 1.41 0.004 Comparative Example 1 93.8 540 1.01 0.032 Comparative Example 2 95.4 553 1.09 0.023

[0115] As can be seen from the above table, the high-conductivity gradient copper alloy slotted wires involved in the various embodiments of the present invention have better conductivity, mechanical properties, fatigue resistance and corrosion resistance than the comparative products. The combined addition of Co, Nb, Ta, Hf, carbon nanotubes and fullerenes, as well as laser-assisted treatment, cryogenic treatment and application of a pulsed magnetic field during solidification are beneficial to improving the above properties.

[0116] The above embodiments are only for illustrating the technical concept and features of the present invention. Their purpose is to enable people familiar with this technology to understand the content of the present invention and implement it accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the scope of protection of the present invention.

Claims

1. A high conductivity gradient copper alloy slot line, characterized in that: The composition includes, by mass percentage, Ag 0.3-0.6%, rare earth elements 0.01-0.1%, Co 0.05-0.15%, Ni 0.02-0.12%, Ba 0.01-0.03%, Nb 0.05-0.8%, Ta 0.01-0.05%, Re 0.003-0.007%, Hf 0.08-0.2%, Mg 0.2-0.6%, carbon nanotubes 0.01-0.05%, fullerene 0.01-0.03%, and the balance is Cu and other inevitable impurities; the rare earth elements are Ce, La, and Y mixed in a mass ratio of (1-2):1:(0.8-1.2).

2. The high conductivity gradient copper alloy slot wire according to claim 1, characterized in that: The carbon nanotubes are multi-walled carbon nanotubes with an outer diameter of 6-13 nm and a length of 2.5-20 μm; the fullerenes are fullerene-C 60 , with an average diameter of 0.7nm.

3. A method for preparing a high conductivity gradient copper alloy slot wire according to any one of claims 1 to 2, characterized in that: The steps include: Step S1, pretreatment of carbon nanotubes and fullerenes: The carbon nanotubes and fullerenes are ultrasonically dispersed in a 3-5% nitric acid solution for 25-35 minutes to remove surface impurities; then, surface modification is performed using a silane coupling agent KH-550, and the mixture is reacted in an 80°C water bath for 2-4 hours. After drying, surface-activated carbon nanotubes and fullerenes are obtained; Step S2, alloy smelting and nanocomposite: electrolytic copper, Ag-Cu master alloy, rare earth element-Cu master alloy, Co-Cu master alloy, Ni-Cu master alloy, Ba-Cu master alloy, Nb-Cu master alloy, Ta-Cu master alloy, Re-Cu master alloy, Hf-Cu master alloy, and Mg-Cu master alloy are added as raw materials into a vacuum induction melting furnace for smelting; surface-activated carbon nanotubes and fullerenes are added into the melt in three portions with an interval of 5 minutes between each addition, while electromagnetic stirring is turned on for uniform stirring to obtain an alloy liquid; Step S3, gradient solidification and texture control: pouring the alloy liquid into a directional solidification mold with a temperature gradient, performing directional solidification at a cooling rate of 10°C / min, and forming an ingot with a columnar crystal orientation; During the solidification process, a pulsed magnetic field is applied to initially form a composition gradient; Step S4, hot isostatic pressing: placing the ingot in a hot isostatic pressing device for hot isostatic pressing to obtain a billet; Step S5, composite processing and gradient strengthening: the billet is rolled using a cumulative rolling process, and during the rolling process, a 60nm thick silver-copper-indium gradient alloy layer is deposited on the surface using ion beam sputtering technology; then a cryogenic treatment is performed to obtain a primary groove line product; Step S6, laser-assisted processing: using a high-power pulsed laser to scan the surface of the initial groove line product; Step S7, heat treatment: placing the copper alloy slot wire in a high-purity argon protective atmosphere furnace for annealing treatment to obtain a high-conductivity gradient copper alloy slot wire.

4. The method for preparing a high conductivity gradient copper alloy slot line according to claim 3, characterized in that: The mass of the silane coupling agent KH-550 in step S1 is 0.8-1.5% of the total mass of the carbon nanotubes and fullerenes; the melting temperature in step S2 is 1200-1220°C and the vacuum degree is 1×10 -5 Pa; the frequency of the electromagnetic stirring in step S2 is 20-25 Hz, and the intensity is 0.5-0.6 T.

5. The method for preparing a high conductivity gradient copper alloy slot line according to claim 3, characterized in that: The bottom temperature of the directional solidification mold with a temperature gradient in step S3 is 275-285° C., and the top temperature is 515-525° C.; the magnetic induction intensity of the pulsed magnetic field in step S3 is 0.8-0.9 T, the frequency is 10-12 Hz, and the pulse width is 500-550 ms.

6. The method for preparing a high conductivity gradient copper alloy slot line according to claim 3, characterized in that: The hot isostatic pressing in step S4 is performed at a pressure of 100-110 MPa, a temperature of 890-910° C., and a time of 5-7 h. The rolling in step S5 is performed at a temperature of 300-320° C., with 8 passes and a deformation of 20% in each pass.

7. The method for preparing a high conductivity gradient copper alloy slotted wire according to claim 3, characterized in that: The mass ratio of silver, copper and indium on the surface of the silver-copper-indium gradient alloy layer in step S5 is 85:10:5; the temperature of the deep cryogenic treatment in step S5 is -195°C to -200°C, and the time is 10-12 hours.

8. The method for preparing a high conductivity gradient copper alloy slotted wire according to claim 3, wherein: The high-power pulse laser in step S6 has a wavelength of 1064 nm, a pulse width of 100 ns, a frequency of 10 Hz, and a power density of 5×10 8 W / cm 2 .

9. The method for preparing a high conductivity gradient copper alloy slotted wire according to claim 3, characterized in that: The scanning speed of the scanning process in step S6 is 50 mm / s, and the spot diameter is 1 mm.

10. The method for preparing a high conductivity gradient copper alloy slotted wire according to claim 3, characterized in that: The annealing treatment in step S7 adopts a three-stage annealing process, first keeping the temperature at 410-430°C for 1-1.2 hours, then heating to 560-590°C for 0.5-0.7 hours, and finally cooling to 470-490°C for 0.8-0.9 hours.