A high-strength, high-conductivity nickel-loaded reduced graphene oxide reinforced copper-based composite material and its preparation method

Abstract

This invention discloses a high-strength, high-conductivity nickel-loaded reduced graphene oxide reinforced copper-based composite material and its preparation method, belonging to the field of metal matrix composite technology. The method first prepares nickel-loaded reduced graphene oxide powder, then atomizes it and adds it to molten copper. An alternating magnetic field and a direct current electric field are applied synergistically to achieve oriented alignment of the reinforcing phases and interfacial strengthening. An ingot is then obtained through electromagnetic stirring casting. Finally, the ingot undergoes homogenization annealing, multi-pass cold drawing deformation + intermediate annealing cyclic processing, rotary forging, and low-temperature aging treatment to obtain a composite material with uniform microstructure and tight interfacial bonding. This material possesses both high strength and high conductivity, with a tensile strength of not less than 700 MPa and an electrical conductivity of not less than 80% IACS, making it suitable for high-requirement electrical materials, electronic interconnects, and aerospace conductor components.

Description

Technical Field

[0001] This invention relates to the field of copper-based composite materials, and in particular to a high-strength, high-conductivity nickel-loaded reduced graphene oxide reinforced copper-based composite material and its preparation method. Background Technology

[0002] Copper and its alloys are widely used in power electronics, heat dissipation, and interconnect materials due to their excellent electrical and thermal conductivity and machinability. However, traditional Cu alloys exhibit an inverse relationship between strength and conductivity; that is, while increasing strength through alloying or work hardening, conductivity is often significantly sacrificed. This contradiction limits their application in cutting-edge fields requiring both high conductivity and high strength, such as high-end electrical materials, electronic interconnects, and conductor components in rail transportation and aerospace.

[0003] In recent years, graphene has been regarded as an ideal reinforcing phase for improving the performance of copper-based composites due to its extremely high intrinsic strength and excellent electron mobility. Theoretically, introducing graphene into a copper matrix is ​​expected to simultaneously improve the strength and conductivity of the material. However, several key challenges are encountered in the actual preparation process: First, the dispersion of graphene sheets in the copper matrix is ​​extremely poor, and they are prone to agglomeration, resulting in uneven distribution of the reinforcing phase; second, the large differences in physicochemical properties between graphene and copper lead to poor interfacial wettability and weak interfacial bonding, making them prone to interfacial debonding under stress; third, the graphene structure is easily destroyed in traditional high-temperature melting processes; and finally, it is difficult to effectively control the orientation of graphene sheets to fully utilize their anisotropic reinforcing effect during subsequent plastic deformation processing.

[0004] In existing technologies, graphene / copper composites prepared by mechanical mixing or electrodeposition generally suffer from weak interfacial bonding and uneven graphene dispersion, leading to unstable material properties and limited performance improvement. Therefore, there is an urgent need in this field for a novel preparation method that can achieve uniform dispersion of graphene in a copper matrix, form strong interfacial bonding, and control its orientation, in order to overcome the bottleneck of the difficulty in simultaneously achieving both strength and conductivity in copper-based composites. Summary of the Invention

[0005] This invention aims to overcome the shortcomings of existing technologies and provide a high-strength, high-conductivity nickel-loaded reduced graphene oxide-reinforced copper-based composite material and its preparation method. This method effectively solves the problems of graphene dispersion, interfacial bonding, and orientation control through innovative surface modification of the reinforcing phase, external field-assisted composite processing, and multi-stage deformation heat treatment.

[0006] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows:

[0007] On one hand, the present invention provides a method for preparing a high-strength, high-conductivity nickel-loaded reduced graphene oxide reinforced copper-based composite material, comprising the following steps:

[0008] (1) Preparation of sheet-like graphene oxide;

[0009] (2) Preparation of nickel-supported reduced graphene oxide powder: The graphene oxide obtained in step (1) is dispersed in ethylene glycol solvent, and Ni-containing... 2+ Solution, stir, so that Ni 2+ The Ni adsorbed on the surface of graphene oxide is then heated to 120–200 °C to undergo a reduction reaction, reducing the graphene oxide to reduced graphene oxide. Simultaneously, the Ni adsorbed on the surface is also reduced. 2+ Nickel nanoparticles were generated by reduction, and after cleaning and drying, nickel-supported reduced graphene oxide powder was obtained, which was then sealed and stored for later use.

[0010] (3) Smelting and composite: The pure copper block is placed in a vacuum smelting furnace for smelting to obtain copper melt; the nickel-loaded reduced graphene oxide powder obtained in step (2) is injected into the copper melt by gas jetting to form a composite melt, and an alternating magnetic field with a frequency of 10-50Hz and a magnetic induction intensity of 0.5-2T and a DC electric field with an intensity of 5-20V / cm are applied to the composite melt at the same time to make the nickel-loaded reduced graphene oxide powder oriented in the copper melt and enhance the interfacial bonding;

[0011] (4) Molding and post-processing: The composite melt processed in step (3) is injected into a crystallizer with electromagnetic stirring function for casting to obtain an ingot; the ingot is subjected to the following steps in sequence to obtain a high-strength, high-conductivity nickel-loaded reduced graphene oxide reinforced copper-based composite material:

[0012] (4.1) Homogenization annealing: carried out at 600-800℃ for 2-6 hours;

[0013] (4.2) Alternating cycle processing of multi-pass cold drawing deformation and intermediate annealing: In multi-pass cold drawing deformation, the area reduction rate of each pass is 8% to 20%; the intermediate annealing is carried out at 200 to 350°C for 5 to 30 minutes;

[0014] (4.3) Rotary forging: carried out at 100-250℃, with radial deformation of 8%-20% per pass, and a total of 3-8 processing passes;

[0015] (4.4) Low temperature aging: 0.5-4h at 200-350℃.

[0016] Further, in step (1), graphene oxide is prepared by the following method: graphite powder with a particle size of 20-60 μm is placed in a mixture of concentrated sulfuric acid and concentrated nitric acid with a volume ratio of 3:1 to 1:1 and reacted at 55-80°C for 5-8 hours to obtain graphene oxide with carboxyl and hydroxyl functional groups on its surface.

[0017] Furthermore, in step (2), the obtained nickel-supported reduced graphene oxide powder is subjected to reduction annealing treatment before use. The specific method of reduction annealing treatment is as follows: it is carried out at 200-400℃ in H2 / Ar atmosphere to completely reduce the partially oxidized nickel nanoparticles during the cleaning and drying process to elemental nickel.

[0018] Further, in step (3), the pure copper block is placed in a vacuum melting furnace and evacuated to a vacuum level of 5×10⁻⁶. 2 After Pa, argon gas is introduced to 0.05 MPa, and the temperature is raised to 1250-1350℃ for melting.

[0019] Furthermore, in step (4), the casting process is carried out under an argon protective atmosphere, and when the surface of the composite melt is 2 cm from the upper edge of the crystallizer, an electromagnetic stirrer with a frequency of 5 Hz and a current of 100 A is started.

[0020] Furthermore, in step (4.2), the cyclic processing of multi-pass cold drawing deformation and intermediate annealing is repeated 2 to 5 times.

[0021] On the other hand, the present invention provides a high-strength, high-conductivity nickel-loaded reduced graphene oxide reinforced copper-based composite material prepared by the above preparation method, wherein the tensile strength of the obtained composite material is not less than 700 MPa and the electrical conductivity is not less than 80% IACS.

[0022] It should be noted that, for ease of description, “graphene oxide” will be referred to as “GO”, “reduced graphene oxide” as “rGO”, and “nickel-supported reduced graphene oxide” as “Ni-rGO”.

[0023] This invention systematically solves the key problems in the preparation of graphene / copper composite materials through a series of specific process steps, from the modification of the reinforcing phase and the control of the composite process to the subsequent deformation heat treatment. Its mechanism of action is mainly reflected in the following aspects: (1) Ni-rGO is prepared by chemical method. Nickel nanoparticles act as a "bridge" connecting rGO and copper matrix. Nickel and carbon can form strong Ni-C bonds, thus firmly bonding with rGO. At the same time, nickel and copper have good miscibility and wettability, which can effectively promote the wetting of the surface of the reinforcing phase by copper liquid during the composite process, and achieve strong metallurgical bonding between the reinforcing phase and copper matrix through the possible formation of Cu-Ni-C transition layers, fundamentally overcoming the problem of weak bonding at the interface of traditional graphene / copper. (2) This invention applies an alternating magnetic field and a DC electric field in the composite melt. The Lorentz force generated by the alternating magnetic field causes the anisotropic Ni-rGO powder to rotate and oriented along the magnetic field direction, thereby optimizing its reinforcing effect. The DC electric field promotes electron migration at the interface, which may activate the interface reaction and further enhance the chemical bonding between Ni-C-Cu. (3) The present invention precisely controls the microstructure through a multi-stage deformation heat treatment process. Among them, the cyclic process design of "multi-pass cold drawing deformation + intermediate annealing" achieves a balance between the accumulation of large deformation and structural relaxation. Multi-pass cold drawing deformation refines the copper matrix grains and further aligns the GO sheets along the cold drawing direction; short-time intermediate annealing releases the processing stress, restores the plasticity of the material, and protects the graphene structure from being destroyed during severe deformation. The subsequent rotary forging process achieves further densification and interface pressing at a lower temperature. The final low-temperature aging treatment helps stabilize the deformed structure and may induce fine precipitation, synergistically improving strength and stability.

[0024] Based on the above principles, the present invention has the following significant advantages compared with the prior art:

[0025] (1) In the Ni-rGO powder prepared by the present invention, Ni nanoparticles act as interface bridges, forming strong Ni-C bonds with rGO and forming good metallurgical bonding with the copper matrix, effectively solving the problem of interface debonding of traditional graphene / copper composite materials, and enabling stress to be efficiently transferred from the matrix to the reinforcing phase.

[0026] (2) In this invention, Ni-rGO powder is sprayed into copper melt by gas injection, which effectively prevents the agglomeration of graphene. In particular, the alternating magnetic field applied during the composite process can promote the oriented alignment of sheet-like Ni-rGO along the magnetic field direction; the synergistic effect of the DC electric field further promotes the interfacial reaction, thereby obtaining a composite structure with uniform distribution of reinforcing phase and good orientation, reducing the anisotropy and instability of performance.

[0027] (3) In this invention, an ingot with uniform composition and dense structure is obtained by electromagnetic stirring casting. After subsequent multi-stage deformation heat treatment process, the strength is greatly improved while avoiding microcracks and graphene damage caused by over-processing, and maintaining high conductivity.

[0028] (4) Through the synergy of various processes, the composite material prepared by this invention successfully breaks the inverse relationship between strength and conductivity. The tensile strength of the material reaches more than 700 MPa, and the conductivity is maintained above 80% IACS, achieving an excellent combination of high strength and high conductivity, and with good performance reproducibility.

[0029] (5) The preparation method of the present invention has clear steps and a clear range of key process parameters. By adjusting the number of cycles of "multi-pass cold drawing deformation + intermediate annealing" and the number of forging passes, the final properties of the material can be adjusted to a certain extent to meet the needs of different application scenarios and have good industrialization prospects. Detailed Implementation

[0030] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0031] This invention provides a method for preparing a high-strength, high-conductivity nickel-loaded reduced graphene oxide reinforced copper-based composite material, the method comprising the following steps performed sequentially:

[0032] (1) Preparation of flake GO: Graphite powder with a particle size of 20-60 μm is placed in a mixture of concentrated sulfuric acid and concentrated nitric acid with a volume ratio of 3:1 to 1:1 and reacted at 55-80℃ for 5-8h to obtain flake GO; This step forms carboxyl and hydroxyl functional groups on the surface of GO, which enhances its adsorption capacity for metal ions and subsequent interfacial bonding performance.

[0033] (2) Preparation of Ni-containing 2+ Solution: NiCl2·6H2O was dissolved in ethylene glycol to prepare a solution with a concentration of 10–30 mg / mL, resulting in a homogeneous and stable Ni-containing solution. 2+ Solution; in this step, ethylene glycol acts as a solvent and can react with Ni. 2+ It forms a complex to prevent hydrolysis and precipitation, thus maintaining solution stability;

[0034] (3) Preparation of GO dispersion: Disperse the GO obtained in step (1) in ethylene glycol at a ratio of 1 to 3 g of GO per 50 mL of ethylene glycol, and sonicate at 30 kHz for 1 to 2 h to obtain a uniformly dispersed GO dispersion; this step ensures that the GO sheets are fully dispersed and avoids agglomeration.

[0035] (4) Preparation of Ni-rGO powder: The Ni-containing powder obtained in step (2) 2+ The solution was added to the GO dispersion from step (3) and stirred for 30–90 min to allow Ni to react. 2+ Ni is adsorbed onto the GO surface, and then heated to 120–200°C to carry out a reduction reaction, reducing GO to rGO, while simultaneously reducing the Ni adsorbed on the surface. 2+ The nickel nanoparticles are reduced to obtain Ni-rGO powder. This step enables the in-situ anchoring of nickel nanoparticles on the rGO surface, forming an interfacial bridging structure. Subsequently, the product is centrifuged and washed to remove residual ions and organic matter, and then vacuum dried at 60–100 °C under an inert atmosphere.

[0036] (5) Reduction annealing and storage: The Ni-rGO powder dried in step (4) is reduced annealed at 200-400℃ in H2 / Ar atmosphere, and then sealed and stored under inert atmosphere or vacuum conditions; this step completely reduces the nickel that may be oxidized to the metallic state and further enhances the interfacial bonding between Ni and rGO.

[0037] (6) Smelting of copper: Place the pure copper block in a vacuum smelting furnace and evacuate it to a vacuum of 5×10⁻⁶. 2 After Pa, argon gas is introduced to 0.05 MPa, and the temperature is raised to 1250-1350℃ to obtain copper melt;

[0038] (7) Addition and dispersion of reinforcing phase: Ni-rGO powder preserved in step (5) is sprayed into the copper melt in step (6) using a gas jet nozzle to obtain a composite melt; this step achieves rapid and uniform dispersion of the reinforcing phase in the copper melt and avoids agglomeration;

[0039] (8) Electromagnetic field synergistic treatment: An alternating magnetic field and a direct current electric field are simultaneously applied to the composite melt obtained in step (7); the frequency of the alternating magnetic field is 10-50 Hz and the magnetic induction intensity is 0.5-2 T; the intensity of the direct current electric field is 5-20 V / cm; in this step, the alternating magnetic field causes Ni-rGO to align in the direction of the magnetic field, while the direct current electric field promotes the migration of electrons and chemical reactions at the interface, thus enhancing the interface bonding together;

[0040] (9) Electromagnetic stirring casting: The composite melt after step (8) is injected into a crystallizer with electromagnetic stirring function. When the melt surface is about 2cm from the upper edge of the crystallizer, electromagnetic stirring is started. The stirring frequency is 5Hz and the current is 100A, so that the melt solidifies under the protective atmosphere of argon to obtain a composite ingot with uniform and dense structure. This step further homogenizes the structure and reduces defects through electromagnetic stirring.

[0041] (10) Post-processing of ingots: The ingots obtained in step (9) are processed as follows:

[0042] (10.1) Homogenization annealing: under argon or vacuum atmosphere, anneal at 600-800℃ for 2-6 hours to eliminate component segregation and stabilize interface structure;

[0043] (10.2) Multi-pass cold drawing deformation: The ingot is cold drawn and deformed, with a reduction area of ​​8% to 20% per pass, to achieve preliminary deformation strengthening and make rGO oriented along the cold drawing deformation direction;

[0044] (10.3) Intermediate annealing: Anneal at 200-350℃ in an argon or vacuum atmosphere for 5-30 minutes to restore the plasticity of the material and maintain the integrity of the graphene structure;

[0045] (10.4) Cyclic processing: Repeat steps (10.2)-(10.3) until the target deformation amount or mechanical property requirements are achieved. Through cyclic processing, deformation is accumulated, grains are refined, and orientation is controlled.

[0046] (10.5) Rotary forging: Rotary forging is carried out at 100-250℃, with radial deformation of 8%-20% per pass and a total of 3-8 processing passes, to further refine the grains, eliminate pores and improve interfacial bonding;

[0047] (10.6) Low temperature aging: Hold at 200-350℃ for 0.5-4h to promote the formation of nano-precipitates and improve the strength and microstructure stability of the material;

[0048] Through the above steps, the high-strength, high-conductivity nickel-loaded reduced graphene oxide reinforced copper-based composite material (hereinafter referred to as "composite material") is finally obtained.

[0049] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments and comparative examples. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0050] Example 1

[0051] This embodiment provides a method for preparing a high-strength, high-conductivity nickel-loaded reduced graphene oxide reinforced copper-based composite material, specifically including the following steps:

[0052] (1) Graphite powder with a particle size of 40 μm was placed in a mixture of concentrated sulfuric acid and concentrated nitric acid with a volume ratio of 2:1 and reacted at 60 °C for 6 h to obtain flake-like GO;

[0053] (2) Dissolve NiCl2·6H2O in ethylene glycol to prepare a Ni-containing solution with a concentration of 20 mg / mL. 2+ Solution;

[0054] (3) Disperse 2g of GO prepared in step (1) in 100mL of ethylene glycol and sonicate at 30kHz for 1.5h to obtain GO dispersion;

[0055] (4) Take the Ni-containing material from step (2) 2+ The solution was added to the GO dispersion in step (3), stirred for 60 min, and then heated to 160 °C for 2 h. After the reaction was completed, the product was centrifuged, washed alternately with deionized water and ethanol, and dried under vacuum at 80 °C to obtain Ni-rGO powder.

[0056] (5) The Ni-rGO powder dried in step (4) was reduced and annealed at 300°C for 1 h in an H2 / Ar (volume ratio 1:9) atmosphere, and then sealed and stored.

[0057] (6) Place the pure copper block in a vacuum melting furnace and evacuate it to a vacuum level of 5×10. 2 After Pa, argon gas is introduced to 0.05 MPa, and the temperature is raised to 1300℃ for melting to obtain copper melt;

[0058] (7) The Ni-rGO powder (added at 0.5% of the mass of copper) prepared in step (5) is sprayed into the copper melt using an argon atomizing nozzle to form a composite melt;

[0059] (8) Apply an alternating magnetic field with a frequency of 30 Hz and a magnetic induction intensity of 1.5 T and a DC electric field with an intensity of 12 V / cm to the composite melt simultaneously for 10 min;

[0060] (9) The composite melt is injected into a crystallizer with electromagnetic stirring function. When the liquid level is 2cm from the upper edge, the electromagnetic stirring is started (frequency 5Hz, current 100A). The ingot is solidified under argon protection.

[0061] (10) Perform the following post-processing on the ingot:

[0062] (10.1) Homogenize and anneal at 750℃ for 4 hours under argon protection;

[0063] (10.2) Perform three passes of cold drawing deformation, with a cross-sectional shrinkage rate of approximately 10% per pass;

[0064] (10.3) After cold drawing and deformation, the intermediate annealing is carried out at 250℃ under argon protection for 20 min;

[0065] (10.4) Repeat steps (10.2) to (10.3) for a total of 3 cycles;

[0066] (10.5) Perform rotary forging at 180℃, with a radial deformation of approximately 12% per pass, for a total of 5 passes;

[0067] (10.6) The final composite material was obtained by performing a low-temperature aging treatment at 300℃ under argon protection for 1 hour.

[0068] Example 2

[0069] The only difference between this embodiment and Embodiment 1 is that in step (10.4), the number of cycles of cold drawing deformation and intermediate annealing is 2.

[0070] Example 3

[0071] The only difference between this embodiment and Embodiment 1 is that in step (10.4), the number of cycles of cold drawing deformation and intermediate annealing is 5.

[0072] Example 4

[0073] The only difference between this embodiment and Embodiment 1 is that in step (10.5), the rotary forging parameters are adjusted to approximately 15% radial deformation per pass, with a total of 5 passes.

[0074] Example 5

[0075] The only difference between this embodiment and Embodiment 1 is that in step (10.5), the rotary forging parameters are adjusted to approximately 10% radial deformation per pass, with a total of 7 passes.

[0076] Comparative Example 1

[0077] The only difference between this comparative example and Example 1 is that in step (1), the reaction temperature for the preparation of GO is 40°C.

[0078] Comparative Example 2

[0079] The only difference between this comparative example and Example 1 is that in step (1), the reaction temperature for the preparation of GO is 90°C.

[0080] Performance Testing and Results Analysis

[0081] The composite material samples prepared in Examples 1-5 and Comparative Examples 1-2 were subjected to performance tests, including hardness, electrical conductivity and tensile properties.

[0082] Hardness testing was performed using an HVS-1000 Vickers hardness tester with a load of 500g and a holding time of 10s. Ten different points were selected on the surface of each sample for testing, and the average value was taken. Electrical conductivity testing was performed using a Sigma 2008B1 digital conductivity meter, measuring the conductivity at room temperature. The results are expressed as a percentage relative to the International Association of Standards for Annealed Copper (IACS). Tensile properties testing was conducted using an AG-I-250kN electronic universal testing machine for room temperature tensile testing to measure tensile strength. The test results are shown in Table 1.

[0083] Table 1 Performance test results of samples from Examples 1-5 and Comparative Examples 1-2

[0084]

[0085] Table 1 shows that the composite materials prepared using the method of this invention within the provided process parameter range (Examples 1-5) all successfully achieved the invention's objectives of tensile strength exceeding 700 MPa and electrical conductivity exceeding 80% IACS, demonstrating the stability and reliability of the process. Example 1, as an example of optimized parameters, demonstrates the best overall performance matching. Specific analysis is as follows: the number of cycles of "multi-pass cold drawing deformation + intermediate annealing" is one of the key parameters for controlling performance. Two cycles (Example 2) were sufficient to achieve the required material, while three cycles (Example 1) further achieved a better balance between strength and conductivity; five cycles (Example 3) demonstrate that by increasing the number of cycles, the performance balance can be flexibly adjusted while maintaining high strength. The rotary forging process also possesses adjustability. The parameter combination of Example 1 (12% deformation per pass, 5 passes) achieved the best results, while Examples 4 and 5 show that by adjusting the amount of deformation per pass and the number of passes, the performance can be fine-tuned within a certain range. The results of Comparative Examples 1 and 2, on the contrary, confirm that the GO preparation temperature must fall within the 55-80℃ range specified in this invention; exceeding this range will lead to a decrease in interface quality and overall performance. In summary, this invention, through a synergistic process system of "Ni-rGO reinforcing phase preparation—electromagnetic field-assisted composite—multi-stage deformation heat treatment," especially the optimized parameter combination shown in Example 1, can stably prepare composite materials with performance far exceeding that of the comparative examples, effectively solving key technical problems such as reinforcing phase dispersion, interface bonding, and performance inversion.

[0086] The foregoing has provided a detailed description of a high-strength, high-conductivity nickel-loaded reduced graphene oxide reinforced copper-based composite material and its preparation method. Specific examples have been used to illustrate the principles and specific implementation methods of the invention. These embodiments are merely illustrative of the methods and core concepts of the invention. It should be noted that any simple modifications, equivalent variations, and alterations made to the above embodiments based on the technical essence of the invention by those skilled in the art fall within the protection scope of the invention.

Claims

1. A method for preparing high-strength and high-conductivity nickel-loaded reduced graphene oxide reinforced copper matrix composite, characterized in that, The method comprises the following steps: (1) preparing sheet-like graphene oxide: placing graphite powder with a particle size of 20-60 μm in a mixed solution of concentrated sulfuric acid and concentrated nitric acid with a volume ratio of 3:1-1:1, and reacting at 55-80 °C for 5-8 h to obtain graphene oxide with carboxyl and hydroxyl functional groups on the surface; (2) Preparation of nickel-loaded reduced graphene oxide powder: the graphene oxide obtained in step (1) is dispersed in an ethylene glycol solvent, a Ni 2+ containing solution is added, stirring is performed, Ni 2+ adsorption on the surface of the graphene oxide is allowed to occur, and then heating to 120-200°C is performed to allow a reduction reaction to occur, so as to reduce the graphene oxide to form reduced graphene oxide, and at the same time, the Ni 2+ adsorbed on the surface is reduced to form nickel nanoparticles, and after washing and drying, the nickel-loaded reduced graphene oxide powder is obtained, which is sealed and stored for later use; (3) smelting and compounding: placing pure copper blocks in a vacuum smelting furnace for smelting to obtain a copper melt; spraying the nickel-loaded reduced graphene oxide powder obtained in step (2) into the copper melt by a gas injection method to form a composite melt, and simultaneously applying an alternating magnetic field with a frequency of 10-50 Hz and a magnetic induction intensity of 0.5-2 T and a direct current electric field with a strength of 5-20 V / cm to the composite melt, so that the nickel-loaded reduced graphene oxide powder is directionally arranged in the copper melt and the interface bonding is enhanced; (4) forming and post-processing: pouring the composite melt treated in step (3) into a crystallizer with an electromagnetic stirring function for casting to obtain an ingot; and sequentially performing the following steps on the ingot to obtain a high-strength and high-conductivity nickel-loaded reduced graphene oxide reinforced copper-based composite material: (4.1) homogenizing annealing: at 600-800 °C for 2-6 h; (4.2) alternating cycle processing of multi-pass cold drawing deformation and intermediate annealing: in the multi-pass cold drawing deformation, the area reduction rate of each pass is 8%-20%; and the intermediate annealing is performed at 200-350 °C for 5-30 min; (4.3) rotary swaging: at 100-250 °C, with a radial deformation amount of 8%-20% per pass, and a total processing pass of 3-8 times; (4.4) low-temperature aging: at 200-350 °C for 0.5-4 h.

2. The production method according to claim 1, characterized by, In step (2), the obtained nickel-loaded reduced graphene oxide powder is further subjected to reduction annealing treatment before use, and the specific method of the reduction annealing treatment is as follows: complete reduction of the partially oxidized nickel nanoparticles to elemental nickel under an H2 / Ar atmosphere at 200-400 °C.

3. The preparation method according to claim 1, characterized in that, In step (3), the pure copper block is put into a vacuum melting furnace, vacuum is extracted to 5 x 10 2 After the vacuum is extracted to 5 x 10~(-3) Pa, argon is filled to 0.05 MPa, and the temperature is raised to 1250-1350°C for melting.

4. The method of claim 1, wherein, In step (4), the casting process is carried out in an argon protective atmosphere, and when the liquid surface of the composite melt is 2 cm away from the upper edge of the crystallizer, electromagnetic stirring with a frequency of 5 Hz and a current of 100 A is started.

5. The preparation method according to claim 1, characterized in that, In step (4.2), the cycle processing of multi-pass cold drawing deformation and intermediate annealing is repeated for 2-5 times.

6. A high-strength and high-conductivity nickel-supported reduced graphene oxide reinforced copper matrix composite prepared by the method of any one of claims 1-5, characterized in that, The obtained composite material has a tensile strength of not less than 700 MPa and an electrical conductivity of not less than 80% IACS.

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