Nano-copper modified graphene reinforced aluminum base material and its preparation method and automotive wiring harness

Abstract

This invention provides a nano-copper-modified graphene-reinforced aluminum base wire, its preparation method, and an automotive wiring harness. The preparation method includes: mixing nano-copper-modified graphene with a first aluminum-based powder to obtain a first mixture; mixing the first mixture with a second aluminum-based powder to obtain a second mixture; mixing the second mixture with a third aluminum-based powder to obtain a third mixture; sintering the third mixture to obtain a nano-copper-modified graphene-reinforced aluminum matrix; and sequentially hot-extruded and drawn the aluminum matrix to obtain the nano-copper-modified graphene-reinforced aluminum base wire. This invention uses nano-copper-modified graphene as the reinforcing phase, significantly improving the interfacial bonding strength between graphene and the aluminum matrix, and avoiding the formation of Al4C3; combined with a three-level gradient dispersion process, it achieves uniform directional arrangement of nano-copper-modified graphene in the wire, improving the tensile strength and conductivity of the wire.

Description

Technical Field

[0001] This invention relates to the field of nanocomposite material preparation technology, specifically to the field of graphene-reinforced aluminum alloys, and particularly to a nano-copper modified graphene-reinforced aluminum alloy base material, its preparation method, and its application in automotive wiring harnesses. Background Technology

[0002] Graphene possesses extremely high strength, excellent electrical conductivity, and good thermal conductivity. Introducing it as a reinforcement into aluminum alloys is expected to significantly improve the mechanical properties (such as strength and hardness) of aluminum alloys while maintaining or even improving their electrical conductivity. This is of great significance for the preparation of high-performance structural and functional materials, and can meet the stringent requirements of aerospace, electronic information and other fields for lightweight, high strength and high electrical conductivity materials.

[0003] However, the preparation process of graphene-reinforced aluminum alloys still faces many challenges, among which the interfacial reaction problem is particularly prominent. Traditional graphene-aluminum composite processes require high-temperature conditions (>400℃), where graphene readily reacts with the aluminum matrix to form aluminum carbide (Al4C3). Al4C3, as a brittle byproduct, significantly reduces the mechanical and electrical properties of the composite aluminum alloy. On the one hand, it weakens the interfacial bonding strength between graphene and the aluminum matrix, leading to a decrease in the mechanical properties of the composite material; on the other hand, Al4C3 has a resistivity >10 Ω·cm. 4 Ω·m, being an insulating material, will severely reduce the electrical conductivity of composite materials.

[0004] CN109590459A discloses an in-situ interface modification method for graphene / magnesium-aluminum alloy. The method utilizes titanium dioxide-modified graphene as a reinforcing phase, which is selectively laser-melted and composited into the magnesium-aluminum alloy. Titanium dioxide improves the wettability of graphene in the magnesium alloy melt, promoting its dispersion within the alloy. Simultaneously, titanium dioxide can undergo a displacement reaction between the magnesium alloy and graphene, improving the interfacial bonding of the graphene / magnesium-aluminum alloy by forming an in-situ interface layer. However, the improvement in conductivity is not ideal.

[0005] CN112593107A discloses an apparatus and method for preparing graphene aluminum alloy. The method involves reducing graphene oxide with oleuropein to increase its C / O ratio, thereby improving the dispersibility of the graphene. Aluminum alloy powder is sprayed onto an atomized graphene dispersion. The graphene in the atomized dispersion effectively adheres to and coats the surface of the aluminum alloy powder particles. Furthermore, the graphene surface in this state can effectively bond with the interface of the aluminum alloy powder particles, resulting in graphene aluminum alloy particles with good uniformity and high quality.

[0006] CN107502772A discloses a method for preparing cast graphene / aluminum alloy composite material. By pretreating the graphene surface through metal coating, boric acid treatment, and the addition of titanium, the method overcomes the disadvantage of poor interfacial wettability between graphene and aluminum alloy matrix, effectively solves the oxidation of graphene and metal at high temperature, and avoids undesirable phenomena such as uneven distribution in the matrix caused by the agglomeration and floating of graphene particles. This improves the comprehensive properties of the composite material, such as heat resistance, strength, and wear resistance.

[0007] Therefore, it is of great significance to provide a graphene-reinforced aluminum matrix composite material with high strength and high electrical conductivity and its preparation method. Summary of the Invention

[0008] To address the shortcomings of existing technologies, the present invention aims to provide a nano-copper-modified graphene-reinforced aluminum base wire, its preparation method, and its application in automotive wiring harnesses. This invention uses nano-copper-modified graphene as the reinforcing phase, significantly improving the interfacial bonding strength between graphene and the aluminum matrix without generating Al4C3. Combined with a three-level gradient dispersion process, it achieves uniform directional arrangement of the nano-copper-modified graphene in the wire, eliminating macroscopic segregation and simultaneously improving the tensile strength and conductivity of the wire.

[0009] To achieve this objective, the present invention employs the following technical solution:

[0010] In a first aspect, the present invention provides a method for preparing a nano-copper modified graphene-reinforced aluminum base material, the preparation method comprising:

[0011] Nano-copper modified graphene is first mixed with a first aluminum-based powder to obtain a first mixture; the first mixture is second mixed with a second aluminum-based powder to obtain a second mixture; the second mixture is third mixed with a third aluminum-based powder to obtain a third mixture.

[0012] The third mixture is sintered to obtain a copper-modified graphene-reinforced aluminum matrix; the aluminum matrix is ​​then subjected to hot extrusion and drawing to obtain the copper-modified graphene-reinforced aluminum matrix material.

[0013] The average particle size of the second aluminum-based powder and the third aluminum-based powder is smaller than that of the first aluminum-based powder.

[0014] This invention uses copper nanoparticles modified with graphene as a reinforcing phase. The copper nanoparticles have good wettability with the aluminum matrix. In addition, in the copper nanoparticle-modified graphene, the copper nanoparticles form Cu-OC bonds with the graphene on the graphene surface. Using copper nanoparticle-modified graphene as a reinforcing phase significantly improves the interfacial bonding strength between graphene and the aluminum matrix, avoids the formation of Al4C3, and effectively improves the conductivity of the aluminum matrix material.

[0015] This invention employs a three-stage gradient dispersion process to mix copper-modified graphene nanoparticles with aluminum-based powder. The purpose of the first mixing step is to break up the soft agglomerates between the copper-modified graphene nanoparticles, providing a basis for their subsequent full dispersion in the aluminum matrix. The purpose of the second mixing step is to achieve uniform micro-region distribution of copper-modified graphene nanoparticles in the aluminum matrix. The third mixing step achieves uniform distribution of copper-modified graphene nanoparticles in the aluminum matrix and eliminates macroscopic segregation.

[0016] The preparation method provided by this invention achieves uniform directional arrangement of copper-modified graphene nanoparticles in aluminum base material, and simultaneously improves the tensile strength and conductivity of copper-modified graphene nanoparticle-reinforced aluminum base material.

[0017] Preferably, the mass ratio of the copper-modified graphene nanoparticles to the first aluminum-based powder is 1:(15-25).

[0018] Preferably, the mass ratio of the first mixture to the second aluminum-based powder is 1:(80-120).

[0019] Preferably, the mass ratio of the second mixture to the third aluminum-based powder is 1:(3-5).

[0020] Preferably, the average particle size of the first aluminum-based powder is 30 μm to 60 μm.

[0021] Preferably, the average particle size of the second aluminum-based powder and the third aluminum-based powder are each independently 3μm to 8μm.

[0022] Preferably, the diameter of the copper nanoparticle-modified graphene is 10 μm to 30 μm.

[0023] Preferably, in the copper nanoparticle-modified graphene, the average particle size of the copper nanoparticles is 8 nm to 12 nm.

[0024] Preferably, the graphene content in the copper-modified nano-graphene is 20wt% to 40wt%.

[0025] Preferably, the first mixing method includes first plasma ball milling mixing.

[0026] Preferably, the second mixing method includes planetary mixing.

[0027] Preferably, the third mixing method includes mixing using a V-type mixer.

[0028] Preferably, the first mixing time is 2h to 6h.

[0029] Preferably, the second mixing time is 1 hour to 3 hours.

[0030] Preferably, the third mixing time is 0.5h to 2h.

[0031] Preferably, the first mixing, the second mixing, and the third mixing are all carried out under an inert atmosphere.

[0032] Preferably, the plasma current intensity of the first plasma ball milling mixture is 1.2A to 1.5A.

[0033] Preferably, the ball-to-material ratio in the first plasma ball milling mixture is (5-10):1.

[0034] Preferably, the rotational speed of the planetary mixing is 200 rpm to 500 rpm.

[0035] Preferably, the sintering method includes spark plasma sintering.

[0036] Preferably, the temperature of the hot extrusion is 350℃~500℃.

[0037] Preferably, the extrusion ratio of the hot extrusion is (10-300):1.

[0038] Preferably, after drawing, the diameter of the nano-copper modified graphene reinforced aluminum baseline material is 0.5 mm to 5 mm.

[0039] Preferably, the temperature of the discharge plasma sintering is 450℃~600℃.

[0040] Preferably, the pressure of the discharge plasma sintering is 40 MPa to 60 MPa.

[0041] Preferably, the discharge plasma sintering time is 3 min to 10 min.

[0042] Preferably, the heating rate of the discharge plasma sintering is 150℃ / min to 300℃ / min.

[0043] In a preferred embodiment of the present invention, the method for preparing the nano-copper modified graphene includes:

[0044] Basic copper carbonate and graphene oxide were mixed by second plasma ball milling in ethanol and then freeze-dried to prepare copper-supported graphene oxide. The copper-supported graphene oxide was then reduced with a reducing gas to obtain the nano-copper modified graphene.

[0045] Preferably, the reducing gas includes an argon-hydrogen mixture, wherein the volume ratio of hydrogen to argon in the argon-hydrogen mixture is (2-8):(8-2).

[0046] Preferably, the flow rate of the reducing gas is 150 mL / min to 200 mL / min.

[0047] Preferably, the reduction treatment temperature is 300℃~400℃.

[0048] Preferably, the reduction process takes 1 to 2 hours.

[0049] Preferably, the current intensity of the second plasma ball milling mixing is 1.2A to 1.5A.

[0050] Preferably, the ball-to-material ratio in the second plasma ball milling mixture is (5-10):1.

[0051] Preferably, the mixing time of the second plasma ball mill is 2h to 4h.

[0052] In a second aspect, the present invention provides a nano-copper modified graphene reinforced aluminum base material prepared by the preparation method described in the first aspect, wherein the nano-copper modified graphene is oriented.

[0053] In this invention, copper-modified graphene nanoparticles are uniformly distributed in an aluminum matrix and, during plastic deformation, flow with the deformation of the aluminum matrix to achieve directional alignment.

[0054] In the copper-modified graphene-reinforced aluminum baseline material provided by this invention, the orientation factor of the copper-modified graphene in the drawing direction is greater than 0.7. The oriented copper-modified graphene forms a "nano-fence" parallel to the drawing direction, increasing dislocation slip resistance and providing a technical basis for high-reliability, lightweight aluminum baseline materials. The oriented arrangement of copper-modified graphene in the aluminum baseline material can simultaneously optimize electronic paths, regulate dislocation movement, and suppress crack propagation. Based on the triple mechanism of electronic path optimization, dislocation movement regulation, and crack propagation suppression, it also breaks through the classical inverse relationship between strength, conductivity, and plasticity.

[0055] Thirdly, the present invention provides an automotive wiring harness comprising the nano-copper modified graphene reinforced aluminum base material described in the second aspect.

[0056] The nano-copper modified graphene-reinforced aluminum baseline provided by this invention has excellent tensile strength and conductivity. When applied to automotive wiring harnesses, it exhibits low resistance and temperature rise, and can adapt to high-voltage operating scenarios above 800V.

[0057] Compared with the prior art, the present invention has the following beneficial effects:

[0058] (1) The present invention uses nano-copper modified graphene as the reinforcing phase, which significantly improves the interfacial bonding strength between graphene and aluminum matrix, and does not generate Al4C3; combined with the three-level gradient dispersion process, the nano-copper modified graphene is uniformly oriented in the wire, eliminating macro segregation and simultaneously improving the tensile strength and conductivity of the wire.

[0059] (2) In the nano-copper modified graphene reinforced aluminum base material provided by the present invention, the orientation factor of the nano-copper modified graphene in the drawing direction is greater than 0.7, which is conducive to the formation of "nano fences" parallel to the drawing direction by the oriented nano-copper modified graphene, and the dislocation slip resistance is increased, providing a technical basis for high reliability and lightweight aluminum base material.

[0060] (3) The nano-copper modified graphene reinforced aluminum baseline provided by the present invention has excellent tensile strength and conductivity. When applied to automotive wiring harnesses, it has low resistance and temperature rise and can adapt to high voltage working scenarios above 800V. Attached Figure Description

[0061] Figure 1 This is a SEM image of the copper nanoparticle-modified graphene provided in Example 1.

[0062] Figure 2 This is a SEM image of the tensile fracture surface of the nano-copper modified graphene reinforced aluminum baseline material provided in Example 1. Detailed Implementation

[0063] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0064] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention; the terms “comprising” and “having” and any variations thereof in this invention are intended to cover non-exclusive inclusion.

[0065] In the description of this invention, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this invention, "a plurality of" means two or more, unless otherwise explicitly defined.

[0066] In one specific embodiment, the present invention provides a method for preparing a nano-copper modified graphene-reinforced aluminum baseline material, the preparation method comprising:

[0067] Nano-copper modified graphene is first mixed with a first aluminum-based powder to obtain a first mixture; the first mixture is second mixed with a second aluminum-based powder to obtain a second mixture; the second mixture is third mixed with a third aluminum-based powder to obtain a third mixture.

[0068] The third mixture is sintered to obtain a copper-modified graphene-reinforced aluminum matrix; the aluminum matrix is ​​then subjected to hot extrusion and drawing to obtain the copper-modified graphene-reinforced aluminum matrix material.

[0069] The average particle size of the second aluminum-based powder and the third aluminum-based powder is smaller than that of the first aluminum-based powder.

[0070] This invention uses copper nanoparticles modified with graphene as a reinforcing phase. The copper nanoparticles have good wettability with the aluminum matrix. In addition, in the copper nanoparticle-modified graphene, the copper nanoparticles form Cu-OC bonds with the graphene on the graphene surface. Using copper nanoparticle-modified graphene as a reinforcing phase significantly improves the interfacial bonding strength between graphene and the aluminum matrix, avoids the formation of Al4C3, and effectively improves the conductivity of the aluminum matrix material.

[0071] This invention employs a three-stage gradient dispersion process to mix copper-modified graphene nanoparticles with aluminum-based powder. The purpose of the first mixing step is to break up the soft agglomerates between the copper-modified graphene nanoparticles, providing a basis for their subsequent full dispersion in the aluminum matrix. The purpose of the second mixing step is to achieve uniform micro-region distribution of copper-modified graphene nanoparticles in the aluminum matrix. The third mixing step achieves uniform distribution of copper-modified graphene nanoparticles in the aluminum matrix and eliminates macroscopic segregation.

[0072] The preparation method provided by this invention achieves uniform directional arrangement of copper-modified graphene nanoparticles in aluminum base material, and simultaneously improves the tensile strength and conductivity of copper-modified graphene nanoparticle-reinforced aluminum base material.

[0073] In some embodiments, the mass ratio of the copper-modified graphene nanoparticles to the first aluminum-based powder is 1:(15-25), for example, it can be 1:15, 1:17, 1:19, 1:21, 1:23 or 1:25, including but not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0074] In some embodiments, the mass ratio of the first mixture to the second aluminum-based powder is 1:(80-120), for example, it can be 1:80, 1:85, 1:90, 1:95, 1:100, 1:105, 1:110, 1:115 or 1:120, including but not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0075] In some embodiments, the mass ratio of the second mixture to the third aluminum-based powder is 1:(3-5), for example, it can be 1:3, 1:3.5, 1:4, 1:4.5 or 1:5, including but not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0076] In this invention, the use of a first aluminum-based powder with a larger particle size is beneficial for breaking down the soft agglomerates of copper-modified graphene and achieving full dispersion of graphene.

[0077] In some embodiments, the average particle size of the first aluminum-based powder is 30 μm to 60 μm, for example, it can be 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm or 60 μm, including but not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0078] In this invention, second and third aluminum-based powders with smaller particle sizes are selected, which can fully contact the copper nano-modified graphene and fill the wrinkles of the copper nano-modified graphene to form a "surface-point" contact mode, thereby achieving close contact between the aluminum matrix and the copper nano-modified graphene, reducing gaps and improving the interface bonding quality.

[0079] In some embodiments, the average particle size of the second aluminum-based powder and the third aluminum-based powder are each independently 3μm to 8μm, for example, 3μm, 4μm, 5μm, 6μm, 7μm or 8μm, including but not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0080] In some embodiments, the diameter of the copper nanoparticle-modified graphene is 10 μm to 30 μm, for example, it can be 10 μm, 15 μm, 20 μm, 25 μm or 30 μm, including but not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0081] In some embodiments, the average particle size of the copper nanoparticles in the copper-modified graphene is 8nm to 12nm, for example, it can be 8nm, 9nm, 10nm, 11nm or 12nm, including but not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0082] In some embodiments, the ratio of the sheet diameter of the copper-modified graphene to the particle diameter of the third aluminum-based powder is (2-6):1, for example, it can be 2:1, 3:1, 4:1, 5:1 or 6:1, including but not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0083] In some embodiments, the graphene content in the nano-copper modified graphene is 20wt% to 40wt%, for example, it can be 20wt%, 25wt%, 30wt%, 35wt% or 40wt%, including but not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0084] In some embodiments, the first mixing method includes first plasma ball milling mixing.

[0085] In this invention, a plasma ball mill mixer is used to mix nano-copper modified graphene with a first aluminum-based powder. During the mixing process, 3 mL / kg to 8 mL / kg of hydrogen peroxide is added to the ball mill control unit, and the ball milling atmosphere is argon.

[0086] In some implementations, the second mixing method includes planetary mixing.

[0087] In some embodiments, the third mixing method includes mixing using a V-type mixer.

[0088] In some implementations, the first mixing time is 2h to 6h, for example, it can be 2h, 3h, 4h, 5h or 6h, including but not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0089] In some embodiments, the second mixing time is 1h to 3h, for example, it can be 1h, 1.5h, 2h, 2.5h or 3h, including but not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0090] In some embodiments, the third mixing time is 0.5h to 2h, for example, it can be 0.5h, 1h, 1.5h or 2h, including but not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0091] In some embodiments, the first mixing, the second mixing, and the third mixing are all carried out under an inert atmosphere.

[0092] In some embodiments, the inert atmosphere includes nitrogen and / or an inert gas. The inert gas includes argon and / or helium.

[0093] In some embodiments, the plasma current intensity of the first plasma ball milling mixture is 1.2A to 1.5A, for example, it can be 1.2A, 1.25A, 1.3A, 1.35A, 1.4A, 1.45A or 1.5A, including but not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0094] In some embodiments, the ball-to-material ratio of the first plasma ball milling mixture is (5-10):1, for example, it can be 5:1, 6:1, 7:1, 8:1, 9:1 or 10:1, including but not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0095] In some embodiments, the rotational speed of the planetary mixing is 200 rpm to 500 rpm, for example, it can be 200 rpm, 250 rpm, 300 rpm, 350 rpm, 400 rpm, 450 rpm or 500 rpm, including but not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0096] In some embodiments, the sintering method includes spark plasma sintering. The spark plasma sintering is performed in a spark plasma sintering furnace.

[0097] In some embodiments, the temperature of the hot extrusion is 350°C to 500°C, for example, it can be 350°C, 400°C, 450°C or 500°C, including but not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0098] In some embodiments, the extrusion ratio of the hot extrusion is (10 to 300):1, for example, it can be 10:1, 50:1, 100:1, 150:1, 200:1, 250:1 or 300:1, including but not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0099] In some embodiments, after drawing, the diameter of the nano-copper modified graphene reinforced aluminum baseline material is 0.5mm to 5mm, for example, it can be 0.5mm, 1mm, 2mm, 3mm, 4mm or 5mm, including but not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0100] In some embodiments, the temperature of the discharge plasma sintering is 450°C to 600°C, for example, 450°C, 500°C, 550°C or 600°C, including but not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0101] In some embodiments, the pressure of the discharge plasma sintering is 40 MPa to 60 MPa, for example, it can be 40 MPa, 45 MPa, 50 MPa, 55 MPa or 60 MPa, including but not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0102] In some embodiments, the discharge plasma sintering time is 3 min to 10 min, for example, it can be 3 min, 4 min, 5 min, 6 min, 7 min, 8 min, 9 min or 10 min, including but not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0103] In some embodiments, the heating rate of the discharge plasma sintering is 150°C / min to 300°C / min, for example, it can be 150°C / min, 200°C / min, 250°C / min or 300°C / min, including but not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0104] In some embodiments, the preparation method of the copper-modified graphene nanoparticles includes:

[0105] Basic copper carbonate and graphene oxide were mixed by second plasma ball milling in ethanol and then freeze-dried to prepare copper-supported graphene oxide. The copper-supported graphene oxide was then reduced with a reducing gas to obtain the nano-copper modified graphene.

[0106] In some embodiments, the reducing gas includes an argon-hydrogen mixture in which the volume ratio of hydrogen to argon is (2-8):(8-2), for example, 2:8, 3:7, 4:6, 5:5, 6:4, 7:3 or 8:2, including but not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0107] In some embodiments, the flow rate of the reducing gas is 150 mL / min to 200 mL / min, for example, it can be 150 mL / min, 160 mL / min, 170 mL / min, 180 mL / min, 190 mL / min or 200 mL / min, including but not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0108] In some embodiments, the temperature of the reduction treatment is 300°C to 400°C, for example, 300°C, 320°C, 340°C, 360°C, 380°C or 400°C, including but not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0109] In some implementations, the reduction process takes 1 to 2 hours, for example, 1 hour, 1.2 hours, 1.4 hours, 1.6 hours, 1.8 hours, or 2 hours, including but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0110] In some embodiments, the current intensity of the second plasma ball milling mixing is 1.2A to 1.5A, for example, it can be 1.2A, 1.25A, 1.3A, 1.35A, 1.4A, 1.45A or 1.5A, including but not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0111] In some embodiments, the ball-to-material ratio of the second plasma ball milling mixture is (5-10):1, for example, it can be 5:1, 6:1, 7:1, 8:1, 9:1 or 10:1, including but not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0112] In some embodiments, the mixing time of the second plasma ball mill is 2h to 4h, for example, it can be 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 5h, 5.5h or 6h, including but not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0113] In another specific embodiment, the present invention provides a nano-copper modified graphene reinforced aluminum base material prepared by the preparation method described in one of the foregoing specific embodiments, wherein the nano-copper modified graphene is oriented.

[0114] In some embodiments, in the copper-modified graphene-reinforced aluminum base material, the orientation factor of the copper-modified graphene along the drawing direction is greater than 0.7, for example, it can be 0.7, 0.72, 0.74, 0.76, 0.78, 0.79, 0.8, 0.81 or 0.82, including but not limited to the listed values. Other unlisted values ​​within the range are also applicable. Preferably, it is 0.78 to 0.82. When the orientation factor of the copper-modified graphene along the drawing direction reaches 0.78 or more, the graphene sheet deflection angle is <10°, and the mean free path of electrons reaches 1.2 μm, which is 3 times that of pure aluminum.

[0115] In this invention, copper-modified graphene nanoparticles are uniformly distributed in aluminum base materials. During plastic deformation, they flow with the deformation of the aluminum matrix, achieving directional alignment. In the copper-modified graphene-reinforced aluminum base materials provided by this invention, the orientation factor of the copper-modified graphene nanoparticles in the drawing direction is greater than 0.7. The directionally aligned copper-modified graphene nanoparticles form "nanofences" parallel to the drawing direction, increasing dislocation slip resistance and providing a technical basis for highly reliable and lightweight aluminum base materials. The directional alignment of copper-modified graphene nanoparticles in aluminum base materials can simultaneously optimize electronic paths, regulate dislocation movement, and suppress crack propagation. Based on the triple mechanism of electronic path optimization, dislocation movement regulation, and crack propagation suppression, it also breaks through the classical inverse relationship between strength, conductivity, and plasticity.

[0116] In yet another embodiment, the present invention provides an automotive wiring harness comprising a nano-copper modified graphene-reinforced aluminum base material as described in another preceding embodiment.

[0117] The nano-copper modified graphene-reinforced aluminum baseline provided by the invention has excellent tensile strength and conductivity. When applied to automotive wiring harnesses, it exhibits low resistance and temperature rise, and can adapt to high-voltage operating scenarios above 800V.

[0118] Example 1

[0119] This embodiment provides a method for preparing a copper-modified graphene-reinforced aluminum base material, the preparation method comprising:

[0120] S1: Preparation of copper-modified graphene nanoparticles: The plasma ball milling current intensity was set to 1.5 A, and the ball-to-material ratio was 6:1. Basic copper carbonate and graphene oxide were mixed in ethanol by plasma ball milling for 4 hours, followed by freeze-drying to prepare copper-supported graphene oxide. Hydrogen and argon gas with a volume ratio of 5:5 and a flow rate of 180 mL / min were introduced to reduce the copper-supported graphene oxide, resulting in copper-modified graphene nanoparticles with an average particle size of 10 nm, a sheet diameter of 20 μm, and a graphene content of 30 wt%. The SEM image of the copper-modified graphene nanoparticles prepared in this embodiment is shown below. Figure 1 As shown, the coverage of nano-copper is >90%.

[0121] S2: Preparation of copper-modified graphene-reinforced aluminum baseline material:

[0122] S2-1: At a mass ratio of 1:19, nano-copper modified graphene and first aluminum-based powder with an average particle size of 45μm were mixed by plasma ball milling. The plasma current density was set to 1.5A, the ball-to-powder ratio was 7:1, and the mixture was mixed for 4 hours to obtain the first mixture.

[0123] S2-2: The first mixture and the second aluminum-based powder with an average particle size of 5μm are planetarily mixed at a mass ratio of 1:99. The planetary mixing speed is set to 300rpm and the mixture is mixed for 2h to obtain the second mixture.

[0124] S2-3: The second mixture and the third aluminum-based powder with an average particle size of 5 μm are mixed in a V-type mixer for 1 hour at a mass ratio of 1:4 to obtain the third mixture;

[0125] S2-4: The third mixture was sintered in a spark plasma sintering furnace. The heating rate was set to 200℃ / min, the sintering temperature to 520℃, the sintering pressure to 50MPa, and the sintering time to 5min to obtain a nano-copper modified graphene reinforced aluminum matrix.

[0126] S2-5: The nano-copper modified graphene reinforced aluminum matrix is ​​hot-extruded at a temperature of 420℃ and an extrusion ratio of 15:1, and then drawn to obtain a nano-copper modified graphene reinforced aluminum matrix material with a diameter of 1.5mm.

[0127] Example 2

[0128] This embodiment provides a method for preparing a copper-modified graphene-reinforced aluminum base material, the preparation method comprising:

[0129] S1: Preparation of copper-modified graphene nanoparticles: The plasma ball milling current intensity was set to 1.2A, the ball-to-material ratio was 5:1, and basic copper carbonate and graphene oxide were mixed in ethanol by plasma ball milling for 6 hours. After freeze drying, copper-supported graphene oxide was prepared. Hydrogen and argon gas with a volume ratio of 2:8 were introduced and the flow rate was set to 150mL / min to reduce the copper-supported graphene oxide, resulting in copper-modified graphene nanoparticles with an average particle size of 8nm, a sheet diameter of 10μm, and a graphene content of 20wt%.

[0130] S2: Preparation of copper-modified graphene-reinforced aluminum baseline material:

[0131] S2-1: At a mass ratio of 1:25, nano-copper modified graphene and first aluminum-based powder with an average particle size of 30μm were mixed by plasma ball milling. The plasma current density was set to 1.3A, the ball-to-powder ratio was 7:1, and the mixture was mixed for 2 hours to obtain the first mixture.

[0132] S2-2: The first mixture and the second aluminum-based powder with an average particle size of 3μm are planetarily mixed at a mass ratio of 1:120. The planetary mixing speed is set to 200rpm and the mixture is mixed for 1h to obtain the second mixture.

[0133] S2-3: Mix the second mixture with the third aluminum-based powder with an average particle size of 4μm in a V-type mixer for 0.5h at a mass ratio of 1:5 to obtain the third mixture;

[0134] S2-4: The third mixture was sintered in a spark plasma sintering furnace. The heating rate was set to 150℃ / min, the sintering temperature to 450℃, the sintering pressure to 40MPa, and the sintering time to 3min, to obtain a nano-copper modified graphene reinforced aluminum matrix.

[0135] S2-5: The nano-copper modified graphene reinforced aluminum matrix is ​​hot-extruded at a temperature of 350°C and an extrusion ratio of 10:1, and then drawn to obtain a nano-copper modified graphene reinforced aluminum matrix material with a diameter of 5 mm.

[0136] Example 3

[0137] This embodiment provides a method for preparing a copper-modified graphene-reinforced aluminum base material, the preparation method comprising:

[0138] S1: Preparation of copper-modified graphene nanoparticles: The plasma ball milling current intensity was set to 1.4A and the ball-to-material ratio was 10:1. Basic copper carbonate and graphene oxide were mixed by plasma ball milling in ethanol for 2 hours and then freeze-dried to prepare copper-supported graphene oxide. Hydrogen and argon gas with a volume ratio of 8:2 were introduced and the flow rate was set to 200mL / min to reduce the copper-supported graphene oxide, resulting in copper-modified graphene nanoparticles with an average particle size of 12nm, a sheet diameter of 30μm, and a graphene content of 40wt%.

[0139] S2: Preparation of copper-modified graphene-reinforced aluminum baseline material:

[0140] S2-1: At a mass ratio of 1:15, nano-copper modified graphene and first aluminum-based powder with an average particle size of 60μm were mixed by plasma ball milling. The plasma current density was set to 1.2A, the ball-to-powder ratio was 5:1, and the mixture was mixed for 3 hours to obtain the first mixture.

[0141] S2-2: The first mixture and the second aluminum-based powder with an average particle size of 8μm are planetarily mixed at a mass ratio of 1:80. The planetary mixing speed is set to 500rpm and the mixture is mixed for 3h to obtain the second mixture.

[0142] S2-3: The second mixture and the third aluminum-based powder with an average particle size of 7 μm are mixed in a V-type mixer for 2 hours at a mass ratio of 1:3 to obtain the third mixture;

[0143] S2-4: The third mixture was sintered in a spark plasma sintering furnace. The heating rate was set to 300℃ / min, the sintering temperature to 600℃, the sintering pressure to 60MPa, and the sintering time to 10min to obtain a nano-copper modified graphene reinforced aluminum matrix.

[0144] S2-5: The nano-copper modified graphene reinforced aluminum matrix is ​​hot-extruded at a temperature of 500℃ and an extrusion ratio of 300:1, and then drawn to obtain a nano-copper modified graphene reinforced aluminum matrix material with a diameter of 0.5mm.

[0145] Example 4

[0146] This embodiment provides a method for preparing nano-copper modified graphene reinforced aluminum base material. Except for step S1, in which copper-loaded graphene oxide is immersed in glucose solution and glucose is used to reduce the copper-loaded graphene oxide without introducing argon-hydrogen mixed gas, the preparation method is the same as in Example 1.

[0147] Example 5

[0148] This embodiment provides a method for preparing a base material reinforced with copper nanoparticles and graphene. Except for the fact that the diameter of the copper nanoparticles and graphene in step S1 is 5 μm, the preparation method is the same as in Example 1.

[0149] Example 6

[0150] This embodiment provides a method for preparing a copper-modified graphene-reinforced aluminum base material. Except for step S2-1, in which the copper-modified graphene is mixed with a first aluminum base powder with an average particle size of 8 μm by plasma ball milling, the preparation method is the same as in Example 1.

[0151] Example 7

[0152] This embodiment provides a method for preparing a copper-modified graphene-reinforced aluminum base material. Except for step S2-1, in which the copper-modified graphene is mixed with a first aluminum-based powder with an average particle size of 70 μm by plasma ball milling, the preparation method is the same as in Example 1.

[0153] Example 8

[0154] This embodiment provides a method for preparing a copper-modified graphene-reinforced aluminum base material. Except for step S2-2, in which the copper-modified graphene is mixed with a second aluminum-based powder with an average particle size of 20 μm, and step S2-3, in which the second mixture is mixed with a third aluminum-based powder with an average particle size of 20 μm, the rest of the preparation method is the same as in Example 1.

[0155] Example 9

[0156] This embodiment provides a method for preparing a nano-copper modified graphene-reinforced aluminum base material. Except for step S2-1, in which nano-copper modified graphene and the first aluminum base powder are mixed at a mass ratio of 1:99, and step S2-2, in which the first mixture and the second aluminum base powder are mixed at a mass ratio of 1:19, the rest of the preparation method is the same as in Example 1.

[0157] Example 10

[0158] This embodiment provides a method for preparing a nano-copper modified graphene reinforced aluminum base material. Except for the plasma ball milling current intensity of 1.1A in step S2-1, the preparation method is the same as in Example 1.

[0159] Comparative Example 1

[0160] This comparative example provides a method for preparing graphene-reinforced aluminum base material. The preparation method is the same as in Example 1 except that step S1 is omitted and in step S2-1, 30 wt% of the mass of the nano-copper modified graphene and graphene with a sheet diameter of 20 μm are used to replace the nano-copper modified graphene.

[0161] Comparative Example 2

[0162] This comparative example provides a method for preparing a nano-copper modified graphene reinforced aluminum base material. Except for step S2, in which the first mixture is directly mixed with the second aluminum base powder and the third aluminum base powder in a planetary mixer at a speed of 300 rpm for 2 hours and then mixed with a V-type mixer for 1 hour, the rest of the preparation method is the same as in Example 1.

[0163] Comparative Example 3

[0164] This comparative example provides a method for preparing a nano-copper modified graphene-reinforced aluminum base material. Except for step S2, in which the nano-copper modified graphene, the first aluminum base powder, the second aluminum base powder, and the third aluminum base powder are directly subjected to planetary mixing at a speed of 300 rpm for 2 hours and V-type mixing for 1 hour, the preparation method is the same as in Example 1.

[0165] Performance testing:

[0166] The tensile fracture surfaces of the copper-modified graphene-reinforced aluminum baseline prepared in Example 1 were subjected to SEM testing. The test results are shown in [Figure 1]. Figure 2 .

[0167] The XRD diffraction pole figures of the aluminum baseline materials provided in all the above embodiments and comparative examples were tested, and the orientation factor of the graphene {002} crystal plane in the drawing direction was calculated. The calculation method is as follows:

[0168] Scanning was performed using Cu-Kα rays at 2θ = 26.5° ± 0.5°; measurement range (Step size 5°), ψ = 0°~85° (step size 5°), then the orientation factor f is calculated according to the following equations 1 and 2:

[0169] f = 2 <cos 2 θ>-1 (Equation 1)

[0170]

[0171] The tensile strength, IACS (International Standard for Annealed Copper) conductivity, carbon content uniformity, and resistance temperature rise of the aluminum baseline materials prepared in all the above embodiments and comparative examples were tested. The test results are shown in Table 1. The test methods are as follows:

[0172] Tensile strength was tested according to ASTM E8 standard;

[0173] Conductivity was tested using the four-probe method. IACS conductivity was calculated based on the resistivity of annealed pure copper at 20°C (1.7241 × 10⁻⁶). -8Based on Ω·m, the conductivity under this condition is defined as 100% conductivity;

[0174] The carbon content distribution uniformity was tested using SEM-EDS, which included: preparing a nine-square grid sample, testing the carbon content of each region, calculating the average value, and using the difference between each region and the average value to characterize the carbon content distribution uniformity.

[0175] The temperature rise of the resistance was tested in accordance with the IEC60092-351 standard.

[0176] Table 1

[0177]

[0178] Based on the test results of Example 1 and Comparative Examples 1 to 3 in Table 1, the present invention uses copper nanoparticle-modified graphene as a reinforcing phase, which significantly improves the interfacial bonding strength between graphene and aluminum matrix, and does not generate Al4C3; combined with a three-level gradient dispersion process, the uniform directional arrangement of copper nanoparticle-modified graphene in the wire is achieved, macroscopic segregation is eliminated, and the tensile strength and conductivity of the wire are simultaneously improved.

[0179] According to the test results of Examples 1 and 4, if argon-hydrogen mixed gas is not used for reduction during the preparation of copper nano-modified graphene, but glucose is chosen for reduction treatment instead, a stable Cu-OC covalent bond cannot be formed at the interface between copper nano-modified graphene and graphene, and the interface between copper nano-modified graphene and aluminum matrix cannot be effectively improved, resulting in unsatisfactory performance improvement.

[0180] According to the test results of Examples 1 and 5, if the sheet diameter of the copper nano-modified graphene is too small, the aluminum-based powder cannot fill the folds of the graphene to form a good "surface-to-point" contact, resulting in gaps between the copper nano-modified graphene and the aluminum matrix, and the interface contact is not ideal, leading to poor performance improvement.

[0181] According to the test results of Examples 1, 6 and 7, if the average particle size of the first aluminum-based powder is too small, it cannot effectively break the soft agglomeration of the copper nano-modified graphene and achieve uniform dispersion of graphene. If the average particle size of the first aluminum-based powder is too large, it will destroy the size matching effect, and the aluminum powder cannot be embedded in the graphene folded area. The aluminum powder and graphene only make edge contact, and the contact area is significantly reduced, which leads to the enrichment of copper nano-modified graphene in the extrusion direction.

[0182] Based on the test results of Examples 1 and 8, if the average particle size of the second and third aluminum-based powders is too large, on the one hand, they cannot fill the wrinkles of the copper-modified graphene nanoparticles to form a good "surface-to-point" contact; on the other hand, the large particle size of the aluminum-based powder is not conducive to improving the specific surface energy, thus failing to improve the interfacial bonding quality. Therefore, when the average particle size of the second and third aluminum-based powders is too large (such as 20 μm in Example 8), it will cause systemic defects. The root cause is that it destroys the size matching effect and reduces the interfacial bonding quality.

[0183] Based on the test results of Examples 1 and 9, if the copper-modified graphene nanoparticles are mixed with more first aluminum-based powder in the first mixing process, and the copper-modified graphene nanoparticles are mixed with less second aluminum-based powder in the second mixing process, on the one hand, mixing the copper-modified graphene nanoparticles with too much first aluminum-based powder is not conducive to the dispersion of the copper-modified graphene nanoparticles; on the other hand, the excessively high content of large-particle aluminum powder not only leads to physical coverage of the graphene but also induces thermodynamic segregation. During mixing, density differences will cause large-particle aluminum powder (2.7 g / cm³) to... 3 ) and copper nanoparticle-modified graphene (2.2 g / cm) 3 Layering. On the other hand, when there is too much large-particle aluminum powder, each aluminum powder can only contact a few points on the edge of the graphene, while ideally point-to-surface contact should be formed. According to molecular dynamics simulations, the binding energy drops sharply from 1.8 eV to 0.9 eV, which directly leads to interfacial debonding rather than graphene fracture during stretching. This conclusion is also consistent with the results of strength reduction in Example 9.

[0184] According to the test results of Examples 1 and 10, if the current density of plasma ball milling is too low during the first mixing process, the effective dispersion of nano-copper modified graphene cannot be achieved, and thus its uniform directional distribution in the aluminum base material cannot be achieved, resulting in unsatisfactory improvement in tensile strength and conductivity.

[0185] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for preparing a nano-copper modified graphene reinforced aluminum baseline material, characterized in that, The preparation method includes: Nano-copper modified graphene is first mixed with a first aluminum-based powder to obtain a first mixture; the first mixture is second mixed with a second aluminum-based powder to obtain a second mixture; the second mixture is third mixed with a third aluminum-based powder to obtain a third mixture. The third mixture is sintered to obtain a copper-modified graphene-reinforced aluminum matrix; the aluminum matrix is ​​then subjected to hot extrusion and drawing to obtain the copper-modified graphene-reinforced aluminum matrix material. The mass ratio of the nano-copper modified graphene to the first aluminum-based powder is 1:(15~25); the mass ratio of the first mixture to the second aluminum-based powder is 1:(80~120); and the mass ratio of the second mixture to the third aluminum-based powder is 1:(3~5). The average particle size of the first aluminum-based powder is 30 μm to 60 μm; the average particle size of the second aluminum-based powder and the third aluminum-based powder are each independently 3 μm to 8 μm. The diameter of the copper-modified graphene nanosheets is 10 μm to 30 μm; The preparation method of the copper-modified graphene nanoparticles includes: Basic copper carbonate and graphene oxide were mixed by second plasma ball milling in ethanol and then freeze-dried to prepare copper-supported graphene oxide. The copper-supported graphene oxide was then reduced with a reducing gas to obtain the nano-copper modified graphene. The reducing gas includes an argon-hydrogen mixture, wherein the volume ratio of hydrogen to argon in the argon-hydrogen mixture is (2~8):(8~2).

2. The preparation method according to claim 1, characterized in that, In the copper-modified graphene, the average particle size of the copper nanoparticles is 8nm~12nm; And / or, in the copper nanoparticle-modified graphene, the graphene content is 20wt%~40wt%.

3. The preparation method according to claim 1, characterized in that, The first mixing method includes first plasma ball milling mixing; And / or, the second mixing method includes planetary mixing; And / or, the third mixing method includes mixing using a V-type mixer; And / or, the first mixing time is 2h~6h; And / or, the second mixing time is 1h to 3h; And / or, the third mixing time is 0.5h~2h; And / or, the first mixing, the second mixing, and the third mixing are all carried out under an inert atmosphere.

4. The preparation method according to claim 3, characterized in that, The plasma current intensity of the first plasma ball milling mixture is 1.2A~1.5A; And / or, the ball-to-material ratio of the first plasma ball milling mixture is (5~10):1; And / or, the rotational speed of the planetary mixing is 200 rpm to 500 rpm.

5. The preparation method according to claim 1, characterized in that, The sintering method includes spark plasma sintering; And / or, the temperature of the hot extrusion is 350°C to 500°C; And / or, the extrusion ratio of the hot extrusion is (10~300):1; And / or, after drawing, the diameter of the nano-copper modified graphene reinforced aluminum baseline material is 0.5mm~5mm.

6. The preparation method according to claim 5, characterized in that, The temperature of the spark plasma sintering is 450℃~600℃; And / or, the pressure of the discharge plasma sintering is 40MPa~60MPa; And / or, the discharge plasma sintering time is 3 min to 10 min; And / or, the heating rate of the discharge plasma sintering is 150℃ / min to 300℃ / min.

7. The preparation method according to claim 1, characterized in that, The flow rate of the reducing gas is 150 mL / min to 200 mL / min; And / or, the temperature of the reduction treatment is 300℃~400℃; And / or, the reduction process takes 1 to 2 hours; And / or, the current intensity of the second plasma ball milling mixing is 1.2A~1.5A; And / or, the ball-to-material ratio of the second plasma ball milling mixture is (5~10):1; And / or, the mixing time for the second plasma ball mill is 2h~4h.

8. A nano-copper modified graphene reinforced aluminum base material prepared by the preparation method according to any one of claims 1 to 7, characterized in that, In the aforementioned copper-modified graphene-reinforced aluminum base material, the copper-modified graphene is oriented.

9. An automotive wiring harness, characterized in that, The automotive wiring harness includes the nano-copper modified graphene reinforced aluminum base material as described in claim 8.

Images