Intermediate alloy and aluminum alloy, preparation methods therefor, and aluminum alloy conductor

Abstract

The present application relates to the technical field of alloy materials. Disclosed are an intermediate alloy and an aluminum alloy, preparation methods therefor, and an aluminum alloy conductor. The intermediate alloy contains a copper-plated carbon component and aluminum coated outside the copper-plated carbon component, wherein the copper-plated carbon component contains a carbon component and a copper plating layer formed on the surface of the carbon component. The aluminum alloy comprises: 0.1-2.5 wt% of the copper-plated carbon component, 0.1-2 wt% of a ceramic component, less than or equal to 0.1 wt% of Si, less than or equal to 0.25 wt% of Fe, 0.01-0.1 wt% of B, 0.005-0.05 wt% of rare earth elements, less than or equal to 0.1 wt% of inevitable impurities, and the balance of Al.

Description

Intermediate alloy and aluminum alloy, and preparation method thereof and aluminum alloy wire

[0001] The present application claims priority to the Chinese patent application No. 202410458926.9, filed on April 15, 2024, and entitled "Intermediate alloy and aluminum alloy, and preparation method thereof and aluminum alloy wire", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] The present application relates to the technical field of alloy materials, in particular to an intermediate alloy and an aluminum alloy, and a preparation method thereof and an aluminum alloy wire. BACKGROUND

[0003] Aluminum wires require materials to have good strength and electrical conductivity to meet the long-span and large-capacity power transmission, and heat resistance to prevent softening for a long time. However, the strength and heat resistance of the material are contradictory to the electrical conductivity in the composition design. The existing technology hopes that the alloy has higher heat resistance and electrical conductivity. Although the electrical conductivity of pure aluminum is good, the strength is low and the heat resistance is poor. In order to meet the performance of heat resistance, strength and electrical conductivity, there are two ideas about high-strength heat-resistant conductive aluminum alloys: one is to add Zr element in 1 series or 6 series alloy to precipitate ZrAl3 to improve the strength and heat resistance, and cooperate with the purification effect of rare earth elements to reduce the melt impurities or reduce the solid solubility of impurities in aluminum to ensure the electrical conductivity. By adding limited Zr element for precipitation strengthening in aluminum melt, the ability of Zr to dissolve and precipitate ZrAl3 is limited, so the heat resistance is limited. The second is to introduce a particulate reinforcing body into the alloy to overcome the contradiction that ZrAl3 strengthening is limited and is not conducive to electrical conductivity. Many existing aluminum composites, especially graphene aluminum composites, have excellent electrical conductivity. However, graphene is easy to agglomerate when directly added to the aluminum melt, and the interface between the aluminum melt and the graphene is easy to produce Al3C4 which is easy to hydrolyze, which ultimately deteriorates the performance of the material and does not play a positive role.

[0004] The existing aluminum alloy cannot simultaneously meet the requirements of good electrical conductivity, high strength and good heat resistance. Therefore, there is an urgent need to develop an aluminum alloy material with excellent heat resistance, high strength and excellent electrical conductivity. SUMMARY

[0005] The purpose of the present application is to overcome the problem that the improvement of heat resistance and strength of the existing aluminum alloy material depends on the addition of Zr, Mg, Cu and other elements that can cause precipitation strengthening, and the existing aluminum alloy cannot simultaneously meet the performance of heat resistance, strength and electrical conductivity. The present application provides an intermediate alloy and an aluminum alloy, and a preparation method thereof and an aluminum alloy wire. The intermediate alloy provided by the present application can effectively improve the function of the conductive carbon material as a conductive reinforcing body, and the aluminum alloy simultaneously has excellent heat resistance, high strength and excellent electrical conductivity.

[0006] To achieve the above object, the first aspect of the present application provides an intermediate alloy, which contains a copper-plated carbon component and aluminum coated on the copper-plated carbon component, wherein the copper-plated carbon component contains a carbon component and a copper plating layer formed on the surface of the carbon component.

[0007] Preferably, in the intermediate alloy, the content of the copper-plated carbon component is ≤40% by volume, and aluminum is the balance.

[0008] Preferably, in the copper-plated carbon component, the mass fraction of Cu element on the surface of the carbon component is 35-60%.

[0009] Preferably, the carbon component is graphene and / or carbon nanotube.

[0010] The second aspect of the present application provides a preparation method of the intermediate alloy of the first aspect, which comprises:

[0011] (1) forming a copper plating layer on the surface of the conductive carbon material to obtain a modified conductive carbon material;

[0012] (2) mixing the modified conductive carbon material with aluminum powder, compacting, and sintering.

[0013] Preferably, in step (1), the conductive carbon material is graphene and / or carbon nanotube.

[0014] Preferably, the flake diameter of the graphene is 10-25 μm, and the thickness is ≤50 nm.

[0015] Preferably, the diameter of the carbon nanotube is 2-10 nm, and the length is 1-20 μm.

[0016] In step (1), the process of forming a copper plating layer on the surface of the conductive carbon material comprises: sequentially purifying and dispersing, roughening, sensitizing, activating, and chemical copper plating on the conductive carbon material.

[0017] Preferably, the operation conditions of the chemical copper plating include: the pH value of the chemical plating solution is 11.5-12, the temperature of the chemical plating is 45-100°C, and the time is 30-70 min.

[0018] Preferably, in step (2), based on the total amount of the modified conductive carbon material and the aluminum powder, the amount of the modified conductive carbon material is 10-40% by volume.

[0019] Preferably, in step (2), the particle size of the aluminum powder is ≤100 μm.

[0020] Preferably, in step (2), the sintering conditions include: the temperature is 400-600°C, and the time is 0.5-1.5 h.

[0021] The third aspect of the present application provides an aluminum alloy raw material composition, which comprises aluminum blocks, aluminum alloy blocks, ceramic particles and intermediate alloy; the intermediate alloy is the intermediate alloy of the first aspect or the intermediate alloy prepared by the method of the second aspect.

[0022] Preferably, the ceramic particles are selected from one or more of AlN, B4C and TiC.

[0023] Preferably, the particle size of the ceramic particles is 10-50 nm.

[0024] The fourth aspect of the present application provides an aluminum alloy prepared from the composition of the third aspect, which comprises 0.1-2.5 wt% copper-plated carbon component, 0.1-2 wt% ceramic component, ≤0.1 wt% Si, ≤0.25 wt% Fe, 0.01-0.1 wt% B, 0.005-0.05 wt% rare earth element, ≤0.1 wt% unavoidable impurities and the balance wt% Al.

[0025] Preferably, the carbon component in the copper-plated carbon component is graphene and / or carbon nanotube.

[0026] Preferably, the ceramic component is selected from one or more of AlN, B4C and TiC.

[0027] Preferably, the rare earth element is selected from one or more of Er, La, Ce and Y.

[0028] The fifth aspect of the present application provides a method for preparing the aluminum alloy of the fourth aspect, which comprises: melting aluminum blocks, aluminum alloy blocks, ceramic particles and intermediate alloy.

[0029] Preferably, the melting process comprises: melting the aluminum blocks, aluminum alloy blocks, ceramic particles and intermediate alloy at 680-730℃, and then refining at 650-750℃.

[0030] The sixth aspect of the present application provides an aluminum alloy wire made of the aluminum alloy of the fourth aspect or the aluminum alloy prepared by the method of the fifth aspect.

[0031] Preferably, the electrical conductivity of the aluminum alloy wire is ≥60% IACS, the tensile strength is ≥270 MPa, the ultimate heat resistance temperature is ≥310℃ and the elongation is ≥1%.

[0032] Compared with the prior art, the present application has at least the following beneficial effects:

[0033] (1) The intermediate alloy provided in the present application contains a carbon component, a copper coating on the carbon component, and an aluminum component coated on the outside of the carbon component and the copper coating. The conductive carbon material is smelted in the form of the intermediate alloy to prepare an aluminum alloy, which can protect the conductive carbon material and solve the problem of interface instability when the conductive carbon material and Al are composited, thereby effectively improving the function of the conductive carbon material as a conductive reinforcement.

[0034] (2) By optimizing the formula of the aluminum alloy and specifically combining specific carbon components and ceramic components with other components, the aluminum alloy described in this application simultaneously has excellent heat resistance, high strength, and excellent electrical conductivity. The carbon component has good electrical conductivity and, as a conductive reinforcement, can alleviate the contradiction between strength and conductivity. The ceramic component, as a sole reinforcement, can greatly improve the heat resistance and strength of the aluminum alloy without relying on elements such as Zr, Mg, and Cu, which have limited strengthening effects.

[0035] (3) The method described in this application introduces conductive carbon materials through the form of intermediate alloys and adopts the casting and melting method to prepare aluminum alloys. On the one hand, it can avoid the interface reaction to form Al3C4, which leads to high interface resistance, and can also protect the conductive carbon materials, thereby maximizing the function of the conductive carbon materials as conductive reinforcements; on the other hand, it can prevent the conductive carbon materials from agglomerating and improve the dispersion uniformity of the conductive carbon materials in the aluminum liquid; on the third hand, it can solve the problem of interface instability when the conductive carbon materials and Al are compounded, thereby making the industrial production of conductive carbon material modified aluminum alloy materials possible. The method described in this application can significantly improve the heat resistance and strength of the prepared aluminum alloy by introducing ceramic particles.

[0036] (4) The method provided in this application can prepare aluminum alloy materials with excellent heat resistance, high strength and excellent electrical conductivity, without the need to add elements such as Zr, Mg, Cu, etc. that can cause precipitation strengthening and have limited strengthening effects, and this method can be realized on a large scale industrially.

[0037] (5) The aluminum alloy wire described in this application simultaneously possesses excellent heat resistance, high strength, and excellent electrical conductivity, as well as good elongation. Specifically, the aluminum alloy wire has a conductivity of ≥60% IACS, a tensile strength of ≥270 MPa, an ultimate heat-resistant temperature of ≥310°C, and an elongation of ≥1%. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] FIG1 is a flow chart of a method for preparing an aluminum alloy wire according to one embodiment of the present application. DETAILED DESCRIPTION

[0039] The specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative and explanatory and are not intended to limit the present application.

[0040] The endpoints of the ranges and any values disclosed herein are not limited to the precise values stated. The endpoints of the ranges are provided as a separate value from but are included in the range. For values which are less than or greater than a stated range, the range is intended to include all values and sub-ranges between the stated values or sub-ranges. For values which are less than or greater than a maximum or minimum limit, the range is intended to include all values and sub-ranges between the maximum or minimum limit and the value.

[0041] The first aspect of the present application provides an intermediate alloy, which comprises a copper-plated carbon component and aluminum coated on the copper-plated carbon component, wherein the copper-plated carbon component comprises a carbon component and a copper plating layer formed on the surface of the carbon component, and the aluminum exists in the form of a single substance.

[0042] The intermediate alloy of the present application is a coated structural material. When the intermediate alloy is used to prepare an aluminum alloy, the interface between the conductive carbon material (carbon component) and Al in this structure has a Cu film, which avoids the formation of Al3C4 due to interface reaction, resulting in high interface resistance, and also protects the conductive carbon material. In addition, the problem of unstable interface between the conductive carbon material and Al during compounding is solved, thereby effectively improving the function of the conductive carbon material as a conductive reinforcing body.

[0043] In the specific embodiments, the content of the copper-plated carbon component in the intermediate alloy is ≤40% by volume, and the aluminum is the balance. In the preferred embodiments, in order to improve the conductivity of the aluminum alloy and at the same time maximize the avoidance of agglomeration of carbon particles, the content of the copper-plated carbon component in the intermediate alloy is 5-25% by volume.

[0044] In the intermediate alloy of the present application, the content of Cu is small and is distributed on the surface of the copper-plated carbon component. In the specific embodiments, micro-area element analysis by EDS energy spectrum analysis shows that the mass fraction of Cu element on the surface of the carbon component in the copper-plated carbon component is 35-60%.

[0045] In the present application, the carbon component can be a material commonly used in the art which has a conductive function. In the specific embodiments, the carbon component can be graphene and / or carbon nanotubes. In the preferred embodiments, the carbon component is graphene.

[0046] The second aspect of the present application provides a preparation method of the intermediate alloy of the first aspect, which comprises:

[0047] (1) forming a copper plating layer on the surface of the conductive carbon material to obtain a modified conductive carbon material;

[0048] (2) mixing the modified conductive carbon material with aluminum powder, making a compact, and sintering.

[0049] The application creatively plates copper on the conductive carbon material, and then coats the conductive carbon material with aluminum powder to obtain a "graphene / copper / aluminum" intermediate alloy uniformly distributed in an aluminum matrix and well bonded at the interface. The intermediate alloy is used to prepare an aluminum alloy, which can maximize the dispersion uniformity of the conductive carbon material in the aluminum liquid and the problem of interface reaction to form Al3C4, thereby making it possible to industrialize the production of the conductive carbon material modified aluminum wire cable.

[0050] In the application, the copper-coated conductive carbon material obtained by electroless copper plating cannot be directly used to prepare an aluminum alloy, and needs to be further coated with aluminum powder. The main reason is that if the copper-coated conductive carbon material is not further coated with aluminum powder, the copper-coated carbon powder is difficult to disperse in the aluminum liquid due to the difference in density, and the Cu film directly contacts the aluminum melt, resulting in poor wettability of the particle surface and the aluminum melt. Mixing the copper-coated conductive carbon material and aluminum powder, making a compact, and sintering can produce chemical diffusion at the Cu-Al interface to realize metallurgical bonding of Cu-Al, that is, a layer of aluminum is coated on the surface of the copper-coated conductive carbon material, and the final material can be added to the Al melt in a manner similar to conventional intermediate alloys. The traditional powder metallurgy method for preparing composite materials is optimized to a casting method suitable for industrial scale. At the same time, in the application, if the conductive carbon material is directly coated with aluminum, Al directly contacts graphene, which will destroy the interface and introduce resistance, resulting in poor electrical conductivity of the aluminum alloy. Therefore, in the application, the conductive carbon material needs to be coated in a specific order.

[0051] In the specific embodiment, the process of forming a copper plating layer on the surface of the conductive carbon material in step (1) includes sequentially purifying and dispersing, roughening, sensitizing, activating, and electroless copper plating the conductive carbon material.

[0052] The purpose of purifying and dispersing is to remove organic impurities on the surface of the conductive carbon material caused by surface molecular adsorption force; and dispersing is needed because the conductive carbon material, especially graphene, has a large intermolecular force and is prone to aggregation. In the application, purifying and dispersing can be performed according to conventional operations in the art. In the specific embodiment, the process of purifying and dispersing the conductive carbon material includes cleaning and dispersing the conductive carbon material in acetone and / or anhydrous ethanol by ultrasonic stirring for 0.5-2 h to clean the organic matter remaining on the surface of the conductive carbon material and disperse the organic matter. The pH value of the graphene after purifying and dispersing can be ensured to be neutral by sufficiently filtering and washing the graphene in distilled water under centrifugal force.

[0053] The purpose of roughening is to chemically roughen the surface of the conductive carbon material, form hydrophilic functional groups on the surface of the conductive carbon material to make it have certain hydrophilicity and roughness, and ensure the adhesion and uniformity of the copper plating layer. In the present application, the conductive carbon material can be roughened by acid pickling and oxidation. In a specific embodiment, the roughening process comprises: mixing concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 1:1 to prepare a roughening solution, immersing the purified and dispersed conductive carbon material in the roughening solution after cooling to room temperature, using ultrasonic dispersion treatment for 10-20 min before and after heating, heating at a temperature of 130-180℃ for 1-4 h, and using distilled water to filter and wash to ensure that the pH value is neutral after roughening is completed.

[0054] The role of sensitization is to adsorb a layer of divalent Sn 2+ with reducing property on the surface of the roughened conductive carbon material, which facilitates subsequent activation treatment. In a specific embodiment, the sensitization process comprises: preparing a sensitization solution by mixing 3-6 mL of 90-96 mass% hydrochloric acid, 2-4 g of SnCl2, and 90-120 mL of distilled water, immersing the roughened conductive carbon material in the sensitization solution for 30-60 min, and then using distilled water to filter and wash after completion.

[0055] The role of activation is to form a layer of elemental Ag on the surface of the conductive carbon material to form uniform catalytic activation points, which facilitates subsequent spontaneous chemical copper plating. In a specific embodiment, the activation process comprises: preparing an activation solution by mixing 0.3-0.8 g of AgNO3, 1-2 mL of NH3·H2O, and 40-60 mL of distilled water, immersing the sensitized conductive carbon material in the activation solution to make the Sn 2+ and Ag + on the surface of the conductive carbon material undergo oxidation-reduction reaction to generate elemental Ag, form plating layer activation points, and the reaction formula is Sn 2+ +2Ag + =2Ag+Sn 4+ .

[0056] In a specific embodiment, the operating conditions of chemical copper plating include: the pH value of the chemical plating solution is 11.5-12, the temperature of chemical plating is 45-100℃, and the time is 30-70 min. In the present application, the composition of the chemical plating solution is not particularly limited and can be selected according to conventional operation. In a more specific embodiment, the process of chemical copper plating comprises: preparing a chemical plating solution with a pH value of 11.5-12 by mixing formaldehyde, C4H4Na2O6, CuSO4·5H2O, NaCO3, NaOH, and distilled water, then placing the activated conductive carbon material in the chemical plating solution and continuously stirring at 45-100℃ for 30-70 min, cooling to room temperature, and then obtaining the surface copper-plated conductive carbon material after suction filtration and vacuum drying.

[0057] In the method of the present application, the amount of Sn and Ag introduced in the sensitization and activation process is small, undetectable, and negligible. The amount of Cu introduced in the electroless copper plating is also small.

[0058] In the method of the present application, the conductive carbon material can be a material with good conductivity as known in the art. In specific embodiments, the conductive carbon material can be graphene and / or carbon nanotube. In preferred embodiments, in order to further improve the conductivity of the prepared aluminum alloy, the conductive carbon material is graphene.

[0059] In preferred embodiments, the flake diameter of the graphene is 10-25 μm. When the flake diameter of the graphene exceeds 25 μm, the dispersion step before electroless copper plating is difficult to complete, and when the flake diameter of the graphene is greater than 10 μm, the conductivity of the aluminum alloy is greatly improved. In the present application, the smaller the thickness of the graphene, the better. In preferred embodiments, the thickness of the graphene is ≤50 nm.

[0060] In preferred embodiments, the diameter of the carbon nanotube is 2-10 nm, and the length is 1-20 μm.

[0061] In step (2) of the present application, the specific process for coating the modified conductive carbon material obtained after surface copper plating with aluminum powder includes: dispersing the modified conductive carbon material by ultrasonic, then mixing the modified conductive carbon material with aluminum powder in a protective atmosphere to obtain a slurry, and then performing suction filtration, vacuum drying, and cold pressing to obtain a block-shaped powder embryo, and then sintering the block-shaped powder embryo in a sintering furnace to obtain an intermediate alloy.

[0062] In specific embodiments, based on the total amount of the modified conductive carbon material and aluminum powder, the amount of the modified conductive carbon material can be 10-40% by volume.

[0063] In the present application, the amount of aluminum powder is not particularly limited, as long as an aluminum film can be formed on the surface of the modified conductive carbon material. In order to avoid agglomeration of the modified conductive carbon material due to the large difference in particle size between the modified conductive carbon material and the aluminum powder, which leads to a large specific surface area of the conductive carbon material compared to the aluminum powder, and thus leads to uneven mixing, the particle size of the aluminum powder should not be too large. In preferred embodiments, the particle size of the aluminum powder in step (2) is ≤100 μm.

[0064] In specific embodiments, the protective atmosphere can be an inert atmosphere such as argon or nitrogen, or a vacuum or low-oxygen environment.

[0065] In the method of the present application, the mixing method in step (2) can be ball milling. In specific embodiments, the operating conditions of the ball milling include: a ball-to-material ratio of 3-8:1, using paraffin as a binder, using anhydrous ethanol and / or acetone as a medium, a rotation speed of 120-160 r / min, and a ball milling time of 30-60 h.

[0066] In step (2), sintering is performed under low-temperature pressurized conditions. In specific embodiments, the temperature of sintering can be 400-600°C, and the time of sintering can be 0.5-1.5h.

[0067] The third aspect of the present application provides an aluminum alloy raw material composition, which contains aluminum blocks, aluminum alloy blocks, ceramic particles, and intermediate alloys; the intermediate alloys are the intermediate alloys of the first aspect or the intermediate alloys prepared by the method of the second aspect.

[0068] In the present application, the intermediate alloys are combined with aluminum blocks, aluminum alloy blocks, and ceramic particles to prepare aluminum alloys by melting, which can protect the conductive carbon material and solve the problem of unstable interface when the conductive carbon material is combined with Al, thereby effectively improving the function of the conductive carbon material as a conductive reinforcing body.

[0069] In specific embodiments, the ceramic particles can be selected from one or more than two of AlN, B4C, and TiC. In preferred embodiments, the particle size of the ceramic particles can be 10-50nm.

[0070] In the present application, the amounts of aluminum blocks, aluminum alloy blocks, ceramic particles, and intermediate alloys are proportioned and adjusted according to the weight percentages of each component in the target product aluminum alloy.

[0071] The fourth aspect of the present application provides an aluminum alloy prepared from the composition of the third aspect, which contains 0.1-2.5wt% of copper-plated carbon components, 0.1-2wt% of ceramic components, ≤0.1wt% of Si, ≤0.25wt% of Fe, 0.01-0.1wt% of B, 0.005-0.05wt% of rare earth elements, ≤0.1wt% of unavoidable impurities, and the balance of Al. The inventors of the present application have found that, by introducing copper-plated carbon components (carbon components with copper-plated surfaces) and ceramic components into the aluminum alloy at specific contents, and limiting the contents of other components within specific ranges, the aluminum alloy can simultaneously have excellent heat resistance, high strength, and excellent electrical conductivity.

[0072] In the aluminum alloy of the present application, the content of Cu is small and is distributed on the surface of the copper-plated carbon components. In specific embodiments, micro-area element analysis by EDS energy spectrum analysis shows that, in the copper-plated carbon components, the mass fraction of Cu elements on the surface of the carbon components is 35-60%.

[0073] In the specific embodiment, the carbon component in the copper-plated carbon component can be a component with good electrical conductivity known in the art, for example, the carbon component can be graphene and / or carbon nanotubes. In the preferred embodiment, in order to further improve the electrical conductivity of the aluminum alloy, the carbon component is graphene. In the present application, the carbon component mainly plays the role of electrical conductivity enhancement and improves the electrical conductivity of the aluminum alloy. If the content of the carbon component is too low, the electrical conductivity of the aluminum alloy is poor; if the content of the carbon component is too high, the elongation of the aluminum alloy is low, and therefore the content of the copper-plated carbon component is limited to 0.1-2.5 wt%.

[0074] In the specific embodiment, the ceramic component can be selected from one or more than two of AlN, B4C and TiC. In the present application, the ceramic component acts as a separate reinforcement and mainly plays the role of second-phase strengthening, which can greatly improve the heat resistance and strength of the aluminum alloy. If the content of the ceramic component is too low, the heat resistance and strength of the aluminum alloy are low; if the content of the ceramic component is too high, it will increase the additional resistance, and the elongation of the aluminum alloy is low and the toughness is poor, which is not conducive to subsequent drawing forming. When the ceramic component is AlN, the content of the ceramic component is 0.2-1 wt%. When the ceramic component is B4C, the content of the ceramic component is 0.28-1.41 wt%. When the ceramic component is TiC, the content of the ceramic component is 0.16-0.78 wt%.

[0075] Si is a basic impurity element in the aluminum alloy, and is the most important impurity element affecting the electrical conductivity of the aluminum alloy. In the present application, the content of Si in the aluminum alloy can be controlled to be ≤0.1 wt%.

[0076] Fe is also a basic impurity element in the aluminum alloy, and is an unavoidable impurity in the actual production of the aluminum alloy. In the actual production, the content of Fe is controlled to react with the impurity Si to form α-Al8Fe2Si, while avoiding the formation of additional resistance β-Al3Fe, so the weight ratio of Fe / Si has little effect on the electrical conductivity of the aluminum alloy. Therefore, in the present application, the content of Fe in the aluminum alloy is controlled to be ≤0.25 wt%.

[0077] Ti, V, Mn and Cr are transition trace impurity elements in the aluminum alloy, which have a great influence on the electrical conductivity of the aluminum alloy. A small amount of B can react with a small amount of transition elements to form borides that are difficult to dissolve and resistant to high temperature and settle at the bottom of the furnace, so that they are precipitated from the solid solution state, thereby improving the electrical conductivity of the aluminum alloy. Therefore, in order to have a high electrical conductivity of the aluminum alloy, the content of B is controlled to be 0.01-0.1 wt% in the present application.

[0078] In the specific embodiment, the rare earth element can be a conventional selection in the art, for example, the rare earth element can be selected from one or more of Er, La, Ce and Y. The main role of the rare earth element is to precipitate with Fe and Si, improve the precipitation distribution of Fe and Si, reduce the adverse effect of Fe and Si on the electrical conductivity of the aluminum alloy, and the rare earth element also has the conventional function of refining grains. Compared with not adding rare earth, the electrical conductivity and strength of the aluminum alloy can be improved, but the effect of reducing the negative impact of Fe and Si on the electrical conductivity is limited, and too much addition is easy to cause pores after the aluminum alloy is solidified, so the content of the rare earth element should not be too high. Therefore, in the present application, the content of the rare earth element can be controlled to be 0.005-0.05% by weight.

[0079] The fifth aspect of the present application provides a method for preparing the aluminum alloy of the fourth aspect, the method comprising:

[0080] The aluminum block, the aluminum alloy block, the ceramic particles and the intermediate alloy are subjected to melting.

[0081] In the present application, the components added in the melting process are matched according to the weight percentages of the components in the aforementioned aluminum alloy.

[0082] In the specific embodiment, the ceramic particles can be selected from one or more of AlN, B4C and TiC. In the preferred embodiment, the particle size of the ceramic particles can be 10-50 nm.

[0083] In the method of the present application, the melting process of step (3) comprises: melting the aluminum block, the aluminum alloy block, the ceramic particles and the intermediate alloy at 680-730°C, and then refining at 650-750°C.

[0084] In the present application, the aluminum alloy block is added in the form of an Al-X intermediate alloy, where X is each alloying element, for example, when X is Si, the aluminum alloy block is an Al-Si alloy block, and when X is B, the aluminum alloy block is an Al-B alloy block.

[0085] In the present application, after obtaining the aluminum alloy liquid, the aluminum alloy liquid can be prepared into other aluminum alloy products according to actual needs. In the specific embodiment, the aluminum alloy liquid can be sequentially subjected to continuous casting, continuous rolling and drawing to obtain an aluminum ingot, an aluminum rod and an aluminum wire. FIG. 1 is a flowchart of a method for preparing an aluminum alloy wire according to one embodiment of the present application.

[0086] The method of the present application alleviates the design contradiction between the existing electrical conductivity and the heat resistance and strength, the heat resistance does not depend on the limited strengthening effect of elements such as Zr, the electrical conductivity enhancer adopts the intermediate alloy to realize the scale production of the electrical conductivity material prepared by the casting method, and the aluminum alloy does not need to be aged after drawing. The product prepared by the present application has better heat resistance and electrical conductivity, low manufacturing cost and simple and safe process.

[0087] The sixth aspect of the present application provides an aluminum alloy wire made of the aluminum alloy of the fourth aspect or the aluminum alloy prepared by the method of the fifth aspect.

[0088] In the specific embodiment, the electrical conductivity of the aluminum alloy wire is ≥60% IACS, the tensile strength is ≥270 MPa, the ultimate heat resistance temperature is ≥310℃, and the elongation is ≥1%.

[0089] In the present application, the electrical conductivity is tested according to the "Electrical Conductivity Test Standard GB / T 3955-2009 Electrical Aluminum Wire". The elongation is tested according to the "Mechanical Test Standard GB / T 228.1-2010 Tensile Test of Metallic Materials". The tensile strength is tested according to the "Mechanical Test Standard GB / T 228.1-2010 Tensile Test of Metallic Materials".

[0090] In the present application, the test method of the ultimate heat resistance temperature is as follows: the aluminum alloy wire is kept at different temperatures for 1h, and then cooled to room temperature, the tensile strength thereof after the heat preservation is T1, and the tensile strength thereof before the heat preservation is T0, the strength high-temperature retention rate is calculated, wherein the calculation method of the strength high-temperature retention rate is T1÷T0×100%, when the strength high-temperature retention rate is greater than 90%, the highest temperature corresponding thereto is taken as the ultimate heat resistance temperature. For example, the aluminum alloy wire is kept at 180-350℃ for 1h, and then cooled to room temperature, and the obtained tensile strength is compared with the tensile strength under the condition without heat preservation, it is found that when the heat preservation temperature is 310℃, the strength retention rate is 90.70%, which is greater than 90%, that is, the heat resistance temperature of the aluminum alloy wire is 310℃.

[0091] The present application will be described in detail by the following examples, but the protection scope of the present application is not limited thereto.

[0092] In the following examples, the methods and processes involved are all conventional operations in the art, and the raw materials used are all commercially available products in the art, unless otherwise specified.

[0093] Examples A1-A3 are used to illustrate the preparation process of the intermediate alloy.

[0094] Example A1

[0095] S1, purification and dispersion: the graphene powder with a flake diameter of 18μm and a thickness of 30nm is cleaned by ultrasonic cleaning and stirring in acetone for 1h to clean the organic matter remaining on the surface and disperse it, and the purified and dispersed graphene is washed in distilled water under centrifugal force until the pH value is neutral;

[0096] S2, roughening: a roughening solution is prepared by mixing concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 1:1, the roughening solution is cooled to room temperature, and then the purified and dispersed graphene is soaked in the solution. Ultrasonic dispersion is performed for 15 minutes before and after heating reaction. The heating reaction conditions include a heating temperature of 150°C and a heating time of 2 hours. Distilled water is used to filter and wash the graphene to a neutral pH value after the roughening is completed.

[0097] S3, sensitization: a sensitization solution is prepared by mixing 5 mL of 96% hydrochloric acid, 3 g of SnCl2, and 100 mL of distilled water. The roughened graphene is soaked in the solution for 50 minutes. Distilled water is used to filter and wash the graphene after the soaking is completed.

[0098] S4, activation: an activation solution is prepared by mixing 0.5 g of AgNO3, 1.5 mL of NH3·H2O, and 50 mL of distilled water. The sensitized graphene is soaked in the solution for 40 minutes to form plated activated points.

[0099] S5, chemical copper plating: a chemical plating solution with a pH value of 11.8 is prepared by mixing formaldehyde, C4H4Na2O6, CuSO4·5H2O, NaCO3, NaOH, and distilled water. The activated graphene is then placed in the chemical plating solution and stirred at 80°C for 1 hour. After cooling to room temperature, the graphene is obtained by suction filtration and vacuum drying. The copper-plated graphene is obtained.

[0100] S6, mixing of copper-plated graphene and aluminum powder (particle size ≤100 μm), blank preparation, and sintering: the copper-plated graphene is ultrasonically dispersed, and then mixed with aluminum powder under argon. The ball milling conditions include a ball-to-material ratio of 5:1, a volume fraction of the copper-plated graphene of 30%, paraffin as a binder, anhydrous ethanol as a medium, a rotation speed of 150 r / min, and a ball milling time of 48 hours. The slurry is obtained by suction filtration, vacuum drying, and cold pressing to obtain a block-shaped powder blank. The block-shaped powder blank is sintered in a sintering furnace at a temperature of 520°C for 1 hour to obtain an intermediate alloy A1. The volume fraction of the copper-plated graphene is 25%, and the remainder is aluminum.

[0101] In step S5, the copper-plated graphene is subjected to micro-area element analysis by EDS energy spectrum analysis. The Cu mass fraction on the surface of the graphene is 70%-75%. The graphene surface in the intermediate alloy A1 is subjected to micro-area element analysis by EDS energy spectrum analysis. The Cu mass fraction on the surface of the graphene is 45%-50%.

[0102] Example A2

[0103] S1, purification and dispersion: graphene powder with a flake size of 25 μm and a thickness of 50 nm is cleaned by ultrasonic stirring in acetone for 2 h to remove organic residues on the surface and disperse the graphene. The purified and dispersed graphene is washed with distilled water under centrifugal force until the pH value is neutral;

[0104] S2, roughening: a roughening solution is prepared by mixing concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 1:1. The roughening solution is cooled to room temperature and then graphene after purification and dispersion is soaked in the solution. Ultrasonic dispersion is performed for 20 min before and after heating. The heating conditions include a temperature of 180 °C and a time of 1 h. After the roughening is completed, the graphene is washed with distilled water until the pH value is neutral;

[0105] S3, sensitization: a sensitization solution is prepared by mixing 6 mL of 96 mass% hydrochloric acid, 4 g of SnCl2, and 100 mL of distilled water. The graphene after roughening is soaked in the solution for 30 min, and then washed with distilled water.

[0106] S4, activation: an activation solution is prepared by mixing 0.8 g of AgNO3, 2 mL of NH 3· H2O, and 60 mL of distilled water. The graphene after sensitization is soaked in the solution for 1 h to form plating activation points.

[0107] S5, chemical copper plating: a chemical plating solution with a pH value of 11.8 is prepared by mixing formaldehyde, C4H4Na2O6, CuSO4·5H2O, NaCO3, NaOH, and distilled water. The graphene after activation is placed in the solution and stirred at 60 °C for 0.5 h. After cooling to room temperature, the graphene is obtained by suction filtration and vacuum drying.

[0108] S6, mixing of copper-plated graphene and aluminum powder (particle size ≤ 100 μm), embryo preparation, and sintering: the copper-plated graphene is dispersed by ultrasonic dispersion, and then mixed with aluminum powder under argon. The ball milling conditions include a ball-to-material ratio of 5:1, a volume fraction of the copper-plated graphene of 40%, paraffin as a binder, anhydrous ethanol as a medium, a rotation speed of 150 r / min, and a ball milling time of 48 h. The slurry is obtained by suction filtration, vacuum drying, and cold pressing to obtain a block-shaped powder embryo. The block-shaped powder embryo is sintered in a sintering furnace at a temperature of 550 °C for 1.5 h to obtain an intermediate alloy A2, wherein the volume fraction of the copper-plated graphene is 35%, and the balance is aluminum.

[0109] In step S5, micro-area element analysis of the copper-plated graphene is performed by EDS energy spectrum analysis, and the Cu mass fraction on the surface of the graphene is 65%-70%. Micro-area element analysis of the graphene surface in the intermediate alloy A2 is performed by EDS energy spectrum analysis, and the Cu mass fraction on the surface of the graphene is 40%-45%.

[0110] Example A3

[0111] S1, purification and dispersion: graphene with a flake size of 10 pm and a thickness of 50 nm was cleaned of surface-remaining organic matter and dispersed by ultrasonic cleaning stirring in acetone for 1.5 h, and the purified and dispersed graphene was sufficiently washed by centrifugal force in distilled water until the pH value was neutral;

[0112] S2, roughening: a roughening solution was prepared by mixing concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 1:1, the roughening solution was cooled to room temperature, and the purified and dispersed graphene was soaked therein, and ultrasonic dispersion treatment was performed for 10 min before and after heating reaction, wherein the heating reaction conditions included a heating temperature of 160°C and a heating time of 1.5 h, and the roughened graphene was washed by filtration with distilled water until the pH value was neutral;

[0113] S3, sensitization: a sensitization solution was prepared by mixing 5 mL of 96 mass% hydrochloric acid, 3 g of SnCl2, and 100 mL of distilled water, the roughened graphene was soaked in the sensitization solution for 40 min, and distilled water was used for washing after the soaking;

[0114] S4, activation: an activation solution was prepared by mixing 0.5 g of AgNO3, 1.5 mL of NH3·H2O, and 50 mL of distilled water, the sensitized graphene was soaked in the activation solution for 1.5 h to form plated activation points;

[0115] S5, chemical copper plating: formaldehyde, C4H4Na2O6, CuSO4·5H2O, NaCO3, NaOH, and distilled water were prepared into a chemical plating solution with a pH value of 11.8, and then the activated graphene was placed in the chemical plating solution for continuous stirring at 80°C for 1 h, and cooled to room temperature, and after suction filtration and vacuum drying, copper-plated graphene was obtained;

[0116] S6, mixing of copper-plated graphene and aluminum powder (particle size ≤ 100 pm), blank preparation, and sintering: the copper-plated graphene was ultrasonically dispersed, and then mixed with aluminum powder under argon by ball milling, the ball milling conditions included a ball-to-material ratio of 5:1, a volume fraction of the copper-plated graphene of 10%, paraffin as a binder, anhydrous ethanol as a medium, a rotation speed of 150 r / min, and a ball milling time of 48 h, to obtain a slurry, the slurry was suction filtered, vacuum dried, and cold-pressed to obtain a blocky powder blank, the blocky powder blank was sintered in a sintering furnace at a temperature of 500°C for 1 h to obtain an intermediate alloy A3, wherein the volume fraction of the copper-plated graphene was 10%, and the balance was aluminum.

[0117] In step S5, the plated copper graphene is subjected to micro-area element analysis by EDS energy spectrum analysis, and the mass fraction of Cu on the surface of the graphene is 75%-80%; the graphene surface in the intermediate alloy A3 is subjected to micro-area element analysis by EDS energy spectrum analysis, and the mass fraction of Cu on the surface of the graphene is 50%-55%.

[0118] Examples B1-B20 are used to illustrate the process for preparing the aluminum alloy wire.

[0119] Example B1

[0120] The aluminum alloy wire of this example contains the following components: plated copper graphene 0.9 wt%, aluminum nitride 0.6 wt%, Si 0.07 wt%, Fe 0.08 wt%, B 0.05 wt%, rare earth elements (Ce) 0.01 wt%, unavoidable impurities ≤0.1 wt%, and aluminum as the balance.

[0121] The method for preparing the aluminum alloy wire includes melting, continuous casting, continuous rolling, and cold drawing into wire, and the specific process includes:

[0122] The aluminum blocks are melted at 700°C, and then aluminum nitride particles (the particle size of AlN is 40 nm) and intermediate alloy Al are added and stirred; the aluminum alloy liquid is obtained by refining and deslagging at 720°C; the aluminum alloy liquid is introduced into a continuous casting machine to cast an aluminum alloy continuous casting billet; the aluminum alloy continuous casting billet is heated to 465°C by a medium-frequency induction heater to soften the aluminum ingot; the continuous casting billet is sent to a continuous rolling mill to roll into an aluminum alloy round rod with a diameter of 9 mm, and the aluminum alloy round rod is water-cooled to room temperature; and the aluminum alloy round rod is drawn into an aluminum alloy wire with a diameter of 1-3 mm.

[0123] Examples B2-Example B16

[0124] The aluminum alloy wire is prepared according to the method of Example B1, except that the content of each component in the aluminum alloy wire is different, and the formulations of Examples B2-Example B16 are shown in Table 1.

[0125] Table 1

[0126] Example B17

[0127] The method of Example B1 is implemented, except that the ceramic particles are replaced by TiC instead of AlN.

[0128] Example B18

[0129] The method of Example B1 is implemented, except that the ceramic particles are replaced by B4C instead of AlN.

[0130] Example B19

[0131] The method of Example B1 was implemented, except that the component composition and content ratio of the aluminum alloy wire were changed, and specifically, the aluminum alloy wire of the present example contained the following components: copper-plated graphene 0.1 wt%, aluminum nitride 2 wt%, Si 0.1 wt%, Fe 0.25 wt%, B 0.1 wt%, rare earth elements (Ce) 0.05 wt%, unavoidable impurities ≤0.1 wt%, and aluminum as the balance.

[0132] Example B20

[0133] The method of Example B1 was implemented, except that the rare earth elements were replaced by Er instead of Ce.

[0134] Example B21

[0135] The method of Example B1 was implemented, except that the rare earth elements were replaced by La instead of Ce.

[0136] Example B22

[0137] The method of Example B1 was implemented, except that the rare earth elements were replaced by Y instead of Ce.

[0138] Example B23

[0139] The method of Example B1 was implemented, except that the intermediate alloy A2 obtained in Example A2 was used to replace the intermediate alloy A1 obtained in Example A1.

[0140] Example B24

[0141] The method of Example B1 was implemented, except that the intermediate alloy A3 obtained in Example A3 was used to replace the intermediate alloy A1 obtained in Example A1.

[0142] Comparative Example 1

[0143] The method of Example B1 was implemented, except that no aluminum nitride was added.

[0144] Comparative Example 2

[0145] The method of Example B1 was implemented, except that the graphene was not prepared into an intermediate alloy, and the graphene was directly smelted.

[0146] Comparative Example 3

[0147] The method of Example B1 was implemented, except that step S6 was not performed, i.e., the graphene plated with copper on the surface was directly smelted, and no aluminum powder was used for coating.

[0148] Comparative Example 4

[0149] The method of Example B1 is followed, except that step S5 is not performed, i.e. the graphene is mixed with aluminum powder and sintered directly, without copper plating.

[0150] Test Example

[0151] The electrical conductivity, tensile strength, ultimate heat resistance temperature and elongation of the aluminum alloy wire prepared in the test examples and comparative examples are tested, and the test results are shown in Table 2.

[0152] Electrical conductivity (%IACS): tested according to the "Electrical Conductivity Test Standard GB / T 3955-2009 Electrical Aluminum Wire".

[0153] Elongation (%): tested according to the "Mechanical Test Standard GB / T 228.1-2010 Tensile Test of Metal Materials".

[0154] Tensile strength (MPa): tested according to the "Mechanical Test Standard GB / T 228.1-2010 Tensile Test of Metal Materials".

[0155] The test method for the ultimate heat resistance temperature (℃) is that the aluminum alloy wire is kept at different temperatures for 1 h, and then cooled to room temperature, and the tensile strength thereof is tested as T1, and the tensile strength thereof before heating and keeping is T0, and the strength high-temperature retention rate is calculated, wherein the calculation method of the strength high-temperature retention rate is T1 ÷ T0 × 100%, and when the strength high-temperature retention rate is greater than 90%, the highest temperature corresponding thereto is taken as the ultimate heat resistance temperature.

[0156] Table 2

[0157] As can be seen from Table 2, the electrical conductivity, tensile strength, ultimate heat resistance temperature and elongation of the aluminum alloy wire obtained according to the technical solutions of the present application are all relatively high.

[0158] As can be seen from Examples B1-B4, with the gradual increase of the Fe content, the electrical conductivity first increases and then decreases, because a small amount of Fe can react with Si to precipitate and reduce the dissolution amount of Si in aluminum, but when the Fe content is relatively high, Al3Fe will increase, resulting in additional resistance, so the electrical conductivity decreases.

[0159] As can be seen from Examples B5-B11, with the gradual increase of the amount of copper-plated graphene added, the electrical conductivity of the material can be effectively improved, but since the X and Y direction scales are micron-level scales, the improvement of the strength of the graphene is limited, and a large amount of addition will seriously reduce the elongation of the final wire.

[0160] From Examples B12-B16 and Comparative Example 3, it can be seen that when the AlN content exceeds 1 wt%, the strength of the material does not improve significantly, but the elongation is severely reduced due to the agglomeration of the particles.

[0161] The above describes the preferred embodiments of the present application, but the present application is not limited thereto. Within the technical concept of the present application, various simple modifications can be made to the technical solutions of the present application, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be considered as disclosed by the present application and fall within the protection scope of the present application.

Claims

1. An intermediate alloy, characterized in that, The intermediate alloy contains a copper-plated carbon component and aluminum coated on the copper-plated carbon component, wherein the copper-plated carbon component contains a carbon component and a copper plating layer formed on the surface of the carbon component.

2. The master alloy according to claim 1, characterized in that The content of the copper-plated carbon component in the intermediate alloy is ≤40% by volume, and aluminum is the remainder. Preferably, in the copper-plated carbon component, the mass fraction of Cu element on the surface of the carbon component is 35-60%.

3. The master alloy according to claim 1 or 2, characterized in that The carbon component is graphene and / or carbon nanotube.

4. A method of producing the master alloy according to any one of claims 1 to 3, characterized in that The method comprises: (1) forming a copper plating layer on the surface of the conductive carbon material to obtain a modified conductive carbon material; (2) mixing the modified conductive carbon material with aluminum powder, compacting and sintering.

5. The method of claim 4, wherein, In step (1), the conductive carbon material is graphene and / or carbon nanotube; Preferably, the flake diameter of the graphene is 10-25 μm, and the thickness is ≤50 nm; Preferably, the diameter of the carbon nanotube is 2-10 nm, and the length is 1-20 μm.

6. The method according to claim 4 or 5, characterized in that, In step (1), the process of forming a copper plating layer on the surface of the conductive carbon material comprises sequentially purifying and dispersing, roughening, sensitizing, activating and chemical copper plating on the conductive carbon material. Preferably, the operating conditions of the chemical copper plating include that the pH value of the chemical plating solution is 11.5-12, the temperature of the chemical plating is 45-100 ℃, and the time is 30-70 min.

7. The method of claim 4, wherein, In step (2), based on the total amount of the modified conductive carbon material and the aluminum powder, the amount of the modified conductive carbon material is 10-40% by volume.

8. The method according to claim 4 or 7, characterized in that, In step (2), the particle size of the aluminum powder is ≤100 μm.

9. The method of claim 4, wherein, In step (2), the sintering conditions include that the temperature is 400-600 ℃, and the time is 0.5-1.5 h.

10. An aluminum alloy feedstock composition characterized by, The composition contains aluminum blocks, aluminum alloy blocks, ceramic particles and intermediate alloy; The intermediate alloy is the intermediate alloy according to any one of claims 1-3 or the intermediate alloy prepared by the method according to any one of claims 4-9.

11. The composition of claim 10, wherein, The ceramic particles are selected from one or more of AlN, B4C and TiC; Preferably, the particle size of the ceramic particles is 10-50 nm.

12. An aluminum alloy characterized by, The aluminum alloy is prepared from the aluminum alloy raw material composition according to claim 10 or 11, and contains 0.1-2.5% by weight of a copper-plated carbon component, 0.1-2% by weight of a ceramic component, ≤0.1% by weight of Si, ≤0.25% by weight of Fe, 0.01-0.1% by weight of B, 0.005-0.05% by weight of rare earth elements, ≤0.1% by weight of unavoidable impurities and the balance of Al.

13. The aluminum alloy of claim 12, wherein, The carbon component in the copper-plated carbon component is graphene and / or carbon nanotube; Preferably, the ceramic component is selected from one or more of AlN, B4C and TiC; Preferably, the rare earth elements are selected from one or more of Er, La, Ce and Y.

14. A method of producing the aluminum alloy of claim 12 or 13, characterized in that, The method comprises melting aluminum blocks, aluminum alloy blocks, ceramic particles and intermediate alloy.

15. The method of claim 14, wherein, The melting process comprises melting the aluminum blocks, aluminum alloy blocks, ceramic particles and intermediate alloy at 680-730 ℃, and then refining at 650-750 ℃.

16. An aluminum alloy wire, characterized by, The aluminum alloy wire is made of the aluminum alloy of claim 12 or 13, or the aluminum alloy made by the method of claim 14 or 15.

17. The aluminum alloy wire of claim 16, wherein, The aluminum alloy wire has an electrical conductivity of ≥60% IACS, a tensile strength of ≥270 MPa, an ultimate heat resistance temperature of ≥310℃, and an elongation of ≥1%.

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