High-strength, high-conductivity and high-temperature-resistant graphene aluminum conductor and preparation method thereof

Abstract

The invention provides a high-strength, high-conductivity and high-temperature-resistant graphene aluminum conductor and a preparation method thereof, and belongs to the technical field of metal conductors. Aluminum powder, graphene and rare earth particles are evenly mixed to obtain composite powder, the composite powder is prepared into a graphene-aluminum composite wire blank through continuous extrusion, large-deformation multi-pass cold drawing is conducted on the wire blank, graphene can be evenly dispersed in the grain boundary of an aluminum matrix, grains are refined, and the graphene-aluminum composite wire blank is obtained. The tensile strength and the conductivity of the graphene aluminum conductor are improved; by adding the rare earth particles, the oxygen content in the aluminum matrix can be controlled, so that the conductivity of the graphene aluminum conductor is improved. The result of the embodiment shows that the method provided by the invention is low in energy consumption, continuous large-scale production can be realized, and the obtained graphene aluminum conductor has the characteristics of high strength, high conductivity and high temperature resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of metal conductors, and in particular to a high-strength, high-conductivity, high-temperature-resistant graphene aluminum conductor and a preparation method thereof. Background Art

[0002] Aluminum and aluminum alloys are widely used as conductors in many industrial fields due to their excellent mechanical, corrosion-resistant, electrical and thermal conductivity. With the rapid development of modern industry and the sharp increase in application demand, the market has put forward higher requirements for aluminum-based materials. However, the tensile strength of pure aluminum materials is only about 150MPa, and its high-temperature performance is poor, which limits its application development.

[0003] At present, by introducing reinforcements into aluminum or aluminum alloy matrices, the yield and tensile strength at room temperature and high temperature can be improved while maintaining the toughness of the matrix material, which largely makes up for the poor tensile strength and high temperature performance of aluminum and its alloys. However, traditional aluminum-based composite materials often use particles or whiskers such as SiC, Al2O3, Ti2AlC and Si3N4 as reinforcements. Although they can improve the tensile strength of the aluminum matrix, these reinforcements will reduce the conductivity of the aluminum-based composite materials. For example, the relevant prior art discloses a Ti2AlC-reinforced conductive wear-resistant aluminum-based composite material, which can obtain an aluminum-based composite material with higher tensile strength, but its room temperature conductivity is low. In order to simultaneously enhance the tensile strength and conductivity of aluminum-based composite materials, studies have been conducted by adding conductive graphene as a reinforcement. For example, the relevant prior art discloses adding graphene to an aluminum matrix, graphene nanosheets are embedded in a mesh metal compound, and the three-dimensional mesh skeleton structure improves the strength of the aluminum-based composite material and reaches a conductivity of 30~37%IACS. Although this method can improve the strength of aluminum-based composite materials, there is still the problem that conductivity needs to be improved.

[0004] In addition, traditional powder metallurgy requires multiple plastic deformations, a long production process, and a complex preparation method. In addition, the batch stability and performance consistency of aluminum-based conductor materials prepared by traditional powder metallurgy methods are poor. Therefore, it is urgent to provide a low-energy consumption, short-process continuous method to obtain high-strength, high-conductivity and high-temperature resistant aluminum-based conductor materials. Summary of the invention

[0005] The purpose of the present invention is to provide a high-strength, high-conductivity, high-temperature-resistant graphene aluminum conductor and a preparation method thereof. The preparation method provided by the present invention has low energy consumption and a short process, and the obtained aluminum conductor has the characteristics of high strength, high conductivity and high temperature resistance.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions: The present invention provides a method for preparing a high-strength, high-conductivity, high-temperature-resistant graphene aluminum conductor, comprising the following steps: (1) Mixing raw material powders to obtain composite powder; The raw material powder includes, by mass content, 0.05-0.5% of graphene, 0.01-0.1% of rare earth particles and the remainder of aluminum powder; (2) continuously extruding the composite powder obtained in step (1) to obtain a graphene aluminum composite wire blank; (3) The graphene aluminum composite material wire blank obtained in step (2) is subjected to multiple cold drawing to obtain a high-strength, high-conductivity, and high-temperature resistant graphene aluminum conductor; the processing rate of the multiple cold drawing is 50-99.5%.

[0007] Preferably, the number of graphene layers in step (1) is 1 to 10.

[0008] Preferably, the graphene sheet thickness is 0.334nm~10nm.

[0009] Preferably, the element types of the rare earth particles in step (1) include one or more of lanthanum, cerium and neodymium.

[0010] Preferably, the particle size of the rare earth particles is 20 μm to 100 μm.

[0011] Preferably, the aluminum powder in step (1) is spherical and / or nearly spherical.

[0012] Preferably, the particle size of the aluminum powder is 100-400 mesh.

[0013] Preferably, the mixing method in step (1) is ball milling; the diameter of the ball milling beads is 4-12 mm, and the ball milling time is 5-15 h.

[0014] Preferably, in step (2), the diameter of the graphene aluminum composite material wire billet is 2-3 mm.

[0015] The present invention also provides a high-strength, high-conductivity, high-temperature resistant graphene aluminum conductor prepared by the preparation method described in the above technical solution, comprising an aluminum matrix and graphene and rare earth particles dispersed in the aluminum matrix; the grain size of the aluminum matrix is ​​2~5μm; the graphene is distributed at the grain interface of the aluminum matrix.

[0016] The invention provides a method for preparing a high-strength, high-conductivity, and high-temperature-resistant graphene aluminum conductor, comprising the following steps: mixing raw material powders to obtain a composite powder; the raw material powders include, by mass content, 0.05-0.5% of graphene, 0.01-0.1% of rare earth particles, and a balance of aluminum powder; continuously extruding the composite powder to obtain a graphene aluminum composite material wire billet; performing multi-pass cold drawing on the graphene aluminum composite material wire billet to obtain a high-strength, high-conductivity, and high-temperature-resistant graphene aluminum conductor; the processing rate of the multi-pass cold drawing is 50-99.5%. The present invention obtains a composite powder by mixing aluminum powder, graphene and rare earth particles uniformly, and prepares the composite powder into a graphene aluminum composite wire billet by continuous extrusion; the wire billet is subjected to multi-pass cold drawing, and the processing rate is controlled at 50-99.5%. The multi-pass cold drawing with large deformation can make the graphene evenly dispersed at the grain boundaries of the aluminum matrix, and the uniformly dispersed graphene plays a role in refining the grain size of the aluminum matrix and strengthening the second phase during the multi-pass cold drawing process. The grains are distributed longitudinally on the longitudinal interface, effectively reducing the number of transverse grain boundaries, reducing the scattering effect of the transverse interface on electrons, and synergistically improving the strength and conductivity of the graphene aluminum conductor; and, during the continuous extrusion and multi-pass cold drawing process, air will be drawn into the aluminum matrix. The present invention can control the oxygen content in the aluminum matrix by adding rare earth particles, thereby improving the conductivity of the graphene aluminum conductor. The method provided by the present invention is simple in process, short in process, highly operable, and can be continuously mass-produced. Compared with the aluminum graphene composite material prepared by the traditional process, the energy consumption is reduced by more than 40%. The results of the embodiments show that the conductivity of the high-strength, high-conductivity and high-temperature resistant graphene aluminum conductor prepared by the present invention can reach 60~64%IACS; the tensile strength can reach 230~260MPa (pure aluminum strength is 90~160MPa); the high-temperature performance is good, and the tensile strength can reach 150MPa at 100°C. The comprehensive performance is significantly better than that of industrial pure aluminum. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a SEM image of the composite powder prepared in Example 1 of the present invention at a magnification of 2000 times; Figure 2 This is a microstructure diagram of the high-strength, high-conductivity, high-temperature-resistant graphene aluminum conductor prepared in Example 1 of the present invention; Figure 3 This is a grain orientation distribution diagram of the high-strength, high-conductivity, high-temperature-resistant graphene aluminum conductor prepared in Example 1 of the present invention; Figure 4 This is a grain boundary distribution diagram of the high-strength, high-conductivity, high-temperature-resistant graphene aluminum conductor prepared in Example 1 of the present invention; Figure 5 This is a grain size distribution histogram of the high-strength, high-conductivity, and high-temperature-resistant graphene aluminum conductor prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0018] The present invention provides a method for preparing a high-strength, high-conductivity, high-temperature-resistant graphene aluminum conductor, comprising the following steps: (1) Mixing raw material powders to obtain composite powder; The raw material powder includes, by mass content, 0.05-0.5% of graphene, 0.01-0.1% of rare earth particles and the remainder of aluminum powder; (2) continuously extruding the composite powder obtained in step (1) to obtain a graphene aluminum composite wire blank; (3) The graphene aluminum composite material wire blank obtained in step (2) is subjected to multiple cold drawing to obtain a high-strength, high-conductivity, and high-temperature resistant graphene aluminum conductor; the processing rate of the multiple cold drawing is 50-99.5%.

[0019] The present invention mixes raw material powders to obtain composite powder.

[0020] In the present invention, the raw material powder includes 0.05-0.5% graphene by mass content, preferably 0.05-0.3%. In an embodiment of the present invention, the mass content of the graphene can be 0.05%, 0.07%, 0.3% or 0.5%. The present invention improves the conductivity and tensile strength of the aluminum conductor by adding graphene as a reinforcement.

[0021] In the present invention, the number of graphene layers is preferably 1 to 10, more preferably 1 to 5; the thickness of the graphene layer is preferably 0.334 nm to 10 nm, more preferably 0.334 nm to 4 nm. The present invention uses graphene of the above size, which is more conducive to full dispersion in the aluminum matrix.

[0022] In the present invention, the raw material powder includes 0.01-0.1% of rare earth particles, preferably 0.01-0.05% by mass content. In an embodiment of the present invention, the mass content of the graphene can be 0.01%, 0.03%, 0.05% or 0.1%. In the present invention, since the continuous extrusion process is non-vacuum, the friction between the material and the mold is large during the extrusion process, the temperature rises, and the aluminum powder is very easy to combine with oxygen and oxidize in a non-vacuum environment. The addition of rare earth can prevent excessive air from being drawn into the continuous extrusion process, control the oxygen content in the aluminum matrix, and thus improve the conductivity of the graphene aluminum conductor.

[0023] In the present invention, the element types of the rare earth particles preferably include one or more of lanthanum, cerium and neodymium, and more preferably lanthanum, cerium or neodymium.

[0024] In the present invention, the particle size of the rare earth particles is preferably 20 μm to 100 μm, more preferably 30 μm to 50 μm. By controlling the particle size of the rare earth particles within the above range, the present invention is more conducive to more uniform mixing with graphene and aluminum powder.

[0025] In the present invention, the raw material powder includes the balance of aluminum powder by mass content. In the present invention, the aluminum powder is used as the matrix of the conductor.

[0026] In the present invention, the aluminum powder is preferably spherical and / or nearly spherical. The spherical and / or nearly spherical aluminum powder used in the present invention has a large specific surface area, and more graphene can be evenly dispersed on the surface of the aluminum powder during the powder mixing process.

[0027] In the present invention, the particle size of the aluminum powder is preferably 100-400 mesh, more preferably 175-400 mesh. In an embodiment of the present invention, the particle size of the aluminum powder may be 100 mesh, 175 mesh, 225 mesh, 325 mesh or 400 mesh. The present invention controls the particle size of the aluminum powder within the above range, which is more conducive to more uniform mixing with graphene and rare earth particles.

[0028] In the present invention, the method of mixing the raw powders is preferably ball milling, the diameter of the ball milling beads is preferably 4-12 mm, more preferably 4-8 mm; the material of the ball milling beads is preferably zirconium oxide; the time of the ball milling is preferably 5-15 hours, more preferably 10-15 hours. In an embodiment of the present invention, the time of the ball milling can be 10 hours, 12 hours, 13 hours or 15 hours. The present invention can promote the graphene and rare earth particles to be evenly distributed on the outer surface of the aluminum powder through ball milling. The present invention has no special limitation on the device of the ball milling, and a conventional ball mill can be used.

[0029] In the present invention, the powder obtained by ball milling is preferably cooled to room temperature after mixing to obtain a composite powder.

[0030] After obtaining the composite powder, the present invention continuously extrude the composite powder to obtain a graphene aluminum composite material wire billet. The present invention forms the composite powder into a graphene aluminum composite material wire billet of a desired size by continuous extrusion.

[0031] In the present invention, the continuous extrusion is preferably carried out in an extruder. The operation method of the continuous extrusion preferably includes: pouring the composite powder into the extrusion cavity of the continuous extruder, performing a first extrusion to obtain a graphene aluminum composite material rod blank; and performing multiple continuous extrusions on the graphene aluminum composite material rod blank to obtain a graphene aluminum composite material wire blank.

[0032] The present invention preferably pours the composite powder into an extrusion cavity of a continuous extruder, performs a first extrusion, and obtains a graphene aluminum composite material rod blank.

[0033] In the present invention, the pouring speed of the composite powder is preferably 20-150 g / s, more preferably 30-100 g / s. The present invention controls the pouring speed of the composite powder within the above range, which is more conducive to improving the density and uniformity of the graphene aluminum composite material rod blank.

[0034] In the present invention, the extrusion speed of the first extrusion is preferably 3-8 r / min, more preferably 4-6 r / min. The present invention controls the extrusion speed of the first extrusion within the above range, which is more conducive to making the structure of the graphene aluminum composite material rod blank more uniform.

[0035] In the present invention, the diameter of the graphene aluminum composite rod blank is preferably 5-16 mm, more preferably 8-12 mm. The present invention first obtains the graphene aluminum composite rod blank of the above diameter, which is more conducive to the subsequent multiple continuous extrusion to obtain the graphene aluminum composite wire blank with the required diameter.

[0036] The present invention preferably cools the rod blank extruded from the continuous extruder to obtain the graphene aluminum composite rod blank. In the present invention, the cooling coolant is preferably a mixture of alcohol and water, and the volume ratio of the alcohol to water is preferably 1: (2-6), more preferably 1: (4-6).

[0037] After obtaining the graphene aluminum composite material rod blank, the present invention preferably subjects the graphene aluminum composite material rod blank to multiple continuous extrusions to obtain a graphene aluminum composite material wire blank.

[0038] In the present invention, the extrusion passes of the multi-pass continuous extrusion are preferably 2 to 10 passes, and more preferably 4 to 8 passes. The present invention can obtain a wire blank with a diameter of 2 to 3 mm through multi-pass continuous extrusion. In the present invention, the cross-section of the wire blank is preferably circular or rectangular.

[0039] The present invention preferably cools the wire billet extruded in multiple passes to obtain the graphene aluminum composite wire billet. In the present invention, the cooling liquid is preferably a mixture of alcohol and water, and the volume ratio of the alcohol to water is preferably 1: (2-6), more preferably 1: (4-6).

[0040] After obtaining the graphene aluminum composite material wire billet, the present invention performs multiple cold drawing on the graphene aluminum composite material wire billet to obtain a high-strength, high-conductivity, and high-temperature resistant graphene aluminum conductor.

[0041] In the present invention, the processing rate of the multi-pass cold drawing is 50-99.5%, preferably 85-99%. In an embodiment of the present invention, the processing rate of the multi-pass cold drawing can be 50%, 85%, 95% or 99%. The present invention controls the processing rate within the above range, has a large deformation amount, and can make the graphene evenly dispersed at the grain boundaries of the aluminum matrix. The uniformly dispersed graphene plays a role in refining the grain size of the aluminum matrix and strengthening the second phase during the multi-pass cold drawing process, and synergistically improves the strength and conductivity of the graphene aluminum conductor. The method provided by the present invention is simple in process, short in process, highly operable, and can be continuously mass-produced.

[0042] The present invention also provides a high-strength, high-conductivity, high-temperature-resistant graphene aluminum conductor prepared by the preparation method described in the above technical solution, comprising an aluminum matrix and graphene and rare earth particles dispersed in the aluminum matrix.

[0043] In the present invention, the grain size of the aluminum matrix is ​​preferably 2-5 μm.

[0044] In the present invention, the grain orientation distribution of the aluminum matrix is ​​preferably a (111) (100) type wire texture.

[0045] In the present invention, the rare earth particles are preferably present in the form of rare earth element and / or rare earth oxide. In the present invention, since the continuous extrusion process is non-vacuum, the friction between the material and the die is large during the extrusion process, the temperature rises, and oxygen is involved in the aluminum powder. The rare earth particles added in the present invention can react with oxygen to form a portion of rare earth oxides, which are present in the high-strength, high-conductivity, and high-temperature resistant graphene aluminum conductor.

[0046] The high-strength, high-conductivity, high-temperature-resistant graphene aluminum conductor provided by the present invention has a relatively small grain size, and the graphene is distributed at the grain interface of the aluminum matrix, which can improve the conductivity and tensile strength of the graphene aluminum conductor.

[0047] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0048] Example 1 A method for preparing a high-strength, high-conductivity, high-temperature resistant graphene aluminum conductor, comprising the following steps: (1) 0.5% of graphene with an average sheet thickness of 3.5 nm, 0.1% of cerium particles with an average particle size of 35 μm, and aluminum powder with a remainder particle size of 200 mesh were placed in a ball mill, and ball milled for 15 hours using zirconia ball milling beads with a diameter of 12 mm to obtain a composite powder; (2) pouring the composite powder obtained in step (1) into the extrusion cavity of a continuous extruder through a hopper and performing a first extrusion, the composite powder pouring speed is 20 g / s, the extrusion speed of the first extrusion is 3 r / min, and a graphene aluminum composite material rod blank with a diameter of 5 mm is obtained. After the rod blank is extruded from the continuous extruder, it is passed through a cooling tank filled with a mixed liquid of alcohol and water (the volume ratio of alcohol to water is 1:6) for cooling to obtain a graphene aluminum composite material rod blank; the graphene aluminum composite material rod blank is subjected to multiple continuous extrusions, the extrusion passes are 2 passes, and the wire blank obtained by the multiple continuous extrusions is passed through a cooling tank filled with a mixed liquid of alcohol and water (the volume ratio of alcohol to water is 1:6) for cooling to obtain a graphene aluminum composite material wire blank with a diameter of 2 mm; (3) The graphene aluminum composite material wire blank obtained in step (2) is subjected to multi-pass cold drawing, wherein the processing rate of the multi-pass cold drawing is 99%, thereby obtaining a high-strength, high-conductivity, and high-temperature resistant graphene aluminum conductor.

[0049] Example 2 A method for preparing a high-strength, high-conductivity, high-temperature resistant graphene aluminum conductor, comprising the following steps: (1) 0.05% of graphene with an average sheet thickness of 7.1 nm, 0.01% of lanthanum particles with an average particle size of 45 μm, and aluminum powder with a remainder particle size of 100 mesh were placed in a ball mill, and ball milled for 10 hours using zirconia ball milling beads with a diameter of 4 mm to obtain a composite powder; (2) pouring the composite powder obtained in step (1) into the extrusion cavity of a continuous extruder through a hopper and performing a first extrusion, the composite powder pouring speed is 100 g / s, the extrusion speed of the first extrusion is 8 r / min, and a graphene aluminum composite material rod blank with a diameter of 16 mm is obtained. After the rod blank is extruded from the continuous extruder, it is passed through a cooling tank filled with a mixed liquid of alcohol and water (the volume ratio of alcohol to water is 1:2) for cooling to obtain a graphene aluminum composite material rod blank; the graphene aluminum composite material rod blank is subjected to multiple continuous extrusions, the extrusion passes are 10 times, and the wire blank obtained by the multiple continuous extrusions is passed through a cooling tank filled with a mixed liquid of alcohol and water (the volume ratio of alcohol to water is 1:2) for cooling to obtain a graphene aluminum composite material wire blank with a diameter of 3 mm; (3) The graphene aluminum composite material wire blank obtained in step (2) is subjected to multi-pass cold drawing, wherein the processing rate of the multi-pass cold drawing is 95%, thereby obtaining a high-strength, high-conductivity, and high-temperature resistant graphene aluminum conductor.

[0050] Example 3 A method for preparing a high-strength, high-conductivity, high-temperature resistant graphene aluminum conductor, comprising the following steps: (1) 0.3% of graphene with an average sheet thickness of 9.5 nm, 0.03% of neodymium particles with an average particle size of 80 μm, and aluminum powder with a remainder particle size of 175-225 mesh were placed in a ball mill, and ball milled for 12 h using 8 mm diameter zirconium oxide ball milling beads to obtain a composite powder; (2) pouring the composite powder obtained in step (1) into the extrusion cavity of a continuous extruder through a hopper and performing a first extrusion, the composite powder pouring speed is 60 g / s, the extrusion speed of the first extrusion is 6 r / min, and a graphene aluminum composite material rod blank with a diameter of 12 mm is obtained. After the rod blank is extruded from the continuous extruder, it is passed through a cooling tank filled with a mixed liquid of alcohol and water (the volume ratio of alcohol to water is 1:4) for cooling to obtain a graphene aluminum composite material rod blank; the graphene aluminum composite material rod blank is subjected to multiple continuous extrusions, the extrusion passes are 6 times, and the wire blank obtained by the multiple continuous extrusions is passed through a cooling tank filled with a mixed liquid of alcohol and water (the volume ratio of alcohol to water is 1:4) for cooling to obtain a graphene aluminum composite material wire blank with a diameter of 3 mm; (3) The graphene aluminum composite material wire blank obtained in step (2) is subjected to multi-pass cold drawing, wherein the processing rate of the multi-pass cold drawing is 50%, thereby obtaining a high-strength, high-conductivity, and high-temperature resistant graphene aluminum conductor.

[0051] Example 4 A method for preparing a high-strength, high-conductivity, high-temperature resistant graphene aluminum conductor, comprising the following steps: (1) 0.07% of graphene with an average sheet thickness of 3.5 nm, 0.05% of cerium particles with a particle size of 80 μm, and aluminum powder with a remainder particle size of 325 mesh were placed in a ball mill, and ball milled for 13 hours using 8 mm diameter zirconium oxide ball milling beads to obtain a composite powder; (2) pouring the composite powder obtained in step (1) into the extrusion cavity of a continuous extruder through a hopper and performing a first extrusion, the composite powder pouring speed is 30 g / s, the extrusion speed of the first extrusion is 4 r / min, and a graphene aluminum composite material rod blank with a diameter of 8 mm is obtained. After the rod blank is extruded from the continuous extruder, it is passed through a cooling tank filled with a mixed liquid of alcohol and water (the volume ratio of alcohol to water is 1:5) for cooling to obtain a graphene aluminum composite material rod blank; the graphene aluminum composite material rod blank is subjected to multiple continuous extrusions, the extrusion passes are 4 passes, and the wire blank obtained by the multiple continuous extrusions is passed through a cooling tank filled with a mixed liquid of alcohol and water (the volume ratio of alcohol to water is 1:5) for cooling to obtain a graphene aluminum composite material wire blank with a diameter of 3 mm; (3) The graphene aluminum composite material wire blank obtained in step (2) is subjected to multi-pass cold drawing, wherein the processing rate of the multi-pass cold drawing is 85%, thereby obtaining a high-strength, high-conductivity, and high-temperature resistant graphene aluminum conductor.

[0052] Comparative Example 1 A method for preparing a high-strength, high-conductivity, high-temperature resistant graphene aluminum conductor, comprising the following steps: (1) 0.07% of graphene with an average sheet thickness of 7.1 nm, 0.05% of cerium particles with an average particle size of 45 μm, and aluminum powder with a remainder particle size of 325 mesh were placed in a ball mill, and ball milled for 13 hours using 8 mm diameter zirconium oxide ball milling beads to obtain a composite powder; (2) pouring the composite powder obtained in step (1) into the extrusion cavity of a continuous extruder through a hopper and performing a first extrusion, the composite powder pouring speed is 30 g / s, the extrusion speed of the first extrusion is 4 r / min, and a graphene aluminum composite material rod blank with a diameter of 8 mm is obtained. After the rod blank is extruded from the continuous extruder, it is passed through a cooling tank filled with a mixed liquid of alcohol and water (the volume ratio of alcohol to water is 1:5) for cooling to obtain a graphene aluminum composite material rod blank; the graphene aluminum composite material rod blank is subjected to multiple continuous extrusions, the extrusion passes are 4 passes, and the wire blank obtained by the multiple continuous extrusions is passed through a cooling tank filled with a mixed liquid of alcohol and water (the volume ratio of alcohol to water is 1:5) for cooling to obtain a graphene aluminum composite material wire blank with a diameter of 3 mm; (3) The graphene aluminum composite material wire blank obtained in step (2) is subjected to multi-pass cold drawing, wherein the processing rate of the multi-pass cold drawing is 30%, thereby obtaining a high-strength, high-conductivity, and high-temperature resistant graphene aluminum conductor.

[0053] Comparative Example 2 A method for preparing a high-strength, high-conductivity, high-temperature resistant graphene aluminum conductor, comprising the following steps: (1) 0.01% of graphene with an average sheet thickness of 3.5 nm, 0.05% of cerium particles with an average particle size of 35 μm, and aluminum powder with a remainder particle size of 325 mesh were placed in a ball mill, and ball milled for 13 hours using 8 mm diameter zirconium oxide ball milling beads to obtain a composite powder; (2) pouring the composite powder obtained in step (1) into the extrusion cavity of a continuous extruder through a hopper and performing a first extrusion, the composite powder pouring speed is 30 g / s, the extrusion speed of the first extrusion is 4 r / min, and a graphene aluminum composite material rod blank with a diameter of 8 mm is obtained. After the rod blank is extruded from the continuous extruder, it is passed through a cooling tank filled with a mixed liquid of alcohol and water (the volume ratio of alcohol to water is 1:5) for cooling to obtain a graphene aluminum composite material rod blank; the graphene aluminum composite material rod blank is subjected to multiple continuous extrusions, the extrusion passes are 4 passes, and the wire blank obtained by the multiple continuous extrusions is passed through a cooling tank filled with a mixed liquid of alcohol and water (the volume ratio of alcohol to water is 1:5) for cooling to obtain a graphene aluminum composite material wire blank with a diameter of 3 mm; (3) The graphene aluminum composite material wire blank obtained in step (2) is subjected to multi-pass cold drawing, wherein the processing rate of the multi-pass cold drawing is 85%, thereby obtaining a high-strength, high-conductivity, and high-temperature resistant graphene aluminum conductor.

[0054] Comparative Example 3 A method for preparing a high-strength, high-conductivity, high-temperature resistant graphene aluminum conductor, comprising the following steps: (1) 0.07% graphene with an average sheet thickness of 3.5 nm and aluminum powder with a residual particle size of 325 mesh were placed in a ball mill and milled for 13 h using 8 mm diameter zirconium oxide ball milling beads to obtain a composite powder; (2) pouring the composite powder obtained in step (1) into the extrusion cavity of a continuous extruder through a hopper and performing a first extrusion, the composite powder pouring speed is 30 g / s, the extrusion speed of the first extrusion is 4 r / min, and a graphene aluminum composite material rod blank with a diameter of 8 mm is obtained. After the rod blank is extruded from the continuous extruder, it is passed through a cooling tank filled with a mixed liquid of alcohol and water (the volume ratio of alcohol to water is 1:5) for cooling to obtain a graphene aluminum composite material rod blank; the graphene aluminum composite material rod blank is subjected to multiple continuous extrusions, the extrusion passes are 4 passes, and the wire blank obtained by the multiple continuous extrusions is passed through a cooling tank filled with a mixed liquid of alcohol and water (the volume ratio of alcohol to water is 1:5) for cooling to obtain a graphene aluminum composite material wire blank with a diameter of 3 mm; (3) The graphene aluminum composite material wire blank obtained in step (2) is subjected to multi-pass cold drawing, wherein the processing rate of the multi-pass cold drawing is 85%, thereby obtaining a high-strength, high-conductivity, and high-temperature resistant graphene aluminum conductor.

[0055] Test Case (1) The composite powder obtained in step (1) of Example 1 is shown in the SEM image at a magnification of 2000 times. Figure 1 As shown. Figure 1 It can be seen that after the raw material powders are mixed and ball milled, the graphene is evenly distributed in the nearly spherical aluminum powder.

[0056] (2) The microstructure of the high-strength, high-conductivity, high-temperature-resistant graphene aluminum conductor prepared in Example 1 is shown in FIG. Figure 2 shown.

[0057] The grain orientation distribution diagram of the high-strength, high-conductivity, high-temperature-resistant graphene aluminum conductor prepared in Example 1 is as follows: Figure 3 As shown. Figure 3 It can be seen that the grain orientation of the high-strength, high-conductivity, and high-temperature resistant graphene aluminum conductor prepared by the present invention is mainly (111) (100) type silk texture.

[0058] The grain boundary distribution diagram of the high-strength, high-conductivity, high-temperature-resistant graphene aluminum conductor prepared in Example 1 is as follows: Figure 4 shown.

[0059] The grain size distribution histogram of the high-strength, high-conductivity, high-temperature-resistant graphene aluminum conductor prepared in Example 1 is as follows: Figure 5 As shown. Figure 5It can be seen that the average grain size of the high-strength, high-conductivity, high-temperature-resistant graphene aluminum conductor prepared in this embodiment is 2.8 μm.

[0060] (3) The performance test results of the high-strength, high-conductivity, high-temperature-resistant graphene aluminum conductors prepared in Examples 1 to 4 and the aluminum conductors prepared in Comparative Examples 1 to 3 are shown in Table 1.

[0061] Table 1 Performance test results of samples prepared in Examples 1 to 4 and Comparative Examples 1 to 3

[0062] As can be seen from Table 1, the graphene aluminum conductor prepared by the present invention has the properties of high strength, high conductivity and high temperature resistance. This is because the present invention controls a large deformation amount during multiple cold drawing, so that the graphene is evenly dispersed at the grain interface of the aluminum matrix, which synergistically improves the strength and conductivity of the graphene aluminum conductor; and by adding rare earth particles, the oxygen content in the aluminum matrix can be controlled, thereby improving the conductivity of the graphene aluminum conductor material. The method provided by the present invention has a simple process, a short process, strong operability, and can be continuously mass-produced. Compared with the aluminum graphene composite material prepared by the traditional process, the energy consumption is reduced by more than 40%, which solves the problems of high energy consumption, long process and complex preparation method existing in the traditional process.

[0063] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a high-strength, high-conductivity, high-temperature resistant graphene aluminum conductor, comprising the following steps: (1) Mixing raw material powders to obtain composite powder; The raw material powder includes, by mass content, 0.05-0.5% of graphene, 0.01-0.1% of rare earth particles and the remainder of aluminum powder; (2) continuously extruding the composite powder obtained in step (1) to obtain a graphene aluminum composite wire blank; (3) The graphene aluminum composite material wire blank obtained in step (2) is subjected to multiple cold drawing to obtain a high-strength, high-conductivity, and high-temperature resistant graphene aluminum conductor; the processing rate of the multiple cold drawing is 50-99.5%.

2. The preparation method according to claim 1, characterized in that: The number of graphene layers in step (1) is 1 to 10.

3. The preparation method according to claim 1 or 2, characterized in that: The graphene sheet thickness is 0.334nm~10nm.

4. The preparation method according to claim 1, characterized in that: The element types of the rare earth particles in step (1) include one or more of lanthanum, cerium and neodymium.

5. The preparation method according to claim 1 or 4, characterized in that: The particle size of the rare earth particles is 20 μm to 100 μm.

6. The preparation method according to claim 1, characterized in that: The aluminum powder in step (1) is spherical and / or nearly spherical.

7. The preparation method according to claim 1 or 6, characterized in that: The particle size of the aluminum powder is 100-400 meshes.

8. The preparation method according to claim 1, characterized in that: The mixing method in step (1) is ball milling; the diameter of the ball milling beads is 4-12 mm, and the ball milling time is 5-15 h.

9. The preparation method according to claim 1, characterized in that: In the step (2), the diameter of the graphene aluminum composite material wire blank is 2-3 mm.

10. The high-strength, high-conductivity, high-temperature-resistant graphene aluminum conductor prepared by the preparation method according to any one of claims 1 to 9 comprises an aluminum matrix and graphene and rare earth particles dispersed in the aluminum matrix; the grain size of the aluminum matrix is ​​2 to 5 μm; and the graphene is distributed at the grain interface of the aluminum matrix.

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