Aluminum alloy material for new energy automobile and preparation method of aluminum alloy material

Abstract

The invention discloses an aluminum alloy material for a new energy automobile and a preparation method of the aluminum alloy material, and belongs to the technical field of aluminum alloy materials. The aluminum alloy material comprises, by mass, 0.5%-0.6% of silicon, 0.95%-1.05% of magnesium, 0.15%-0.25% of copper, 0.1%-0.2% of iron, 0.02%-0.025% of titanium, 0.05%-0.15% of chromium, smaller than or equal to 0.15% of manganese, smaller than or equal to 0.25% of zinc, smaller than or equal to 0.1% of other inevitable impurity elements and the balance aluminum. According to the aluminum alloy material, the electrical conductivity of the aluminum alloy material is improved by optimizing the content of alloy elements, reducing the grain boundary and dislocation density, enhancing material heat treatment and the like, and the electrical conductivity and the mechanical property are jointly improved. The aluminum base material of the aluminum alloy material adopts 99.70% high-purity aluminum and 6061 aluminum alloy extruded white material blends, the advantages of the 99.70% high-purity aluminum and the 6061 aluminum alloy extruded white material blends can be combined, and the aluminum alloy material with conductivity and high strength is obtained.

Description

Technical Field

[0001] The present invention belongs to the technical field of aluminum alloys, and specifically relates to an aluminum alloy material for new energy vehicles and a preparation method thereof. Background Art

[0002] As the global automotive industry transforms towards new energy, lightweighting has become a key path to improve the range and energy efficiency of new energy vehicles. Aluminum alloy materials have become the preferred material for core structures such as new energy vehicle bodies, battery systems, and motor components due to their low density and high specific strength. With the development of new energy vehicles, new energy vehicles have put forward higher requirements for aluminum alloys.

[0003] The conductivity of the aluminum alloy material used in the motor current collector will directly affect the charging speed and overall performance of the battery. The current collector, as the carrier of current transmission inside the battery, needs to efficiently conduct electrons through a low-resistance path. Therefore, the conductivity of this part of the aluminum alloy material becomes an important indicator to measure its performance. Its improvement also plays a significant role in optimizing vehicle performance, enhancing driving experience and improving safety.

[0004] The electrical conductivity of aluminum alloys used in current new energy vehicles is generally low. The solid solution of some strengthening elements in aluminum alloys, such as magnesium, silicon and zinc, will significantly reduce the electrical conductivity of aluminum alloys. In addition, the increase in electrical conductivity is often accompanied by a decrease in the material strength of the aluminum alloy and a decrease in corrosion resistance. Therefore, there is an urgent need to develop a high-conductivity, high-performance aluminum alloy material to meet the high requirements of new energy vehicles for aluminum alloy materials. Summary of the invention

[0005] The object of the present invention is to provide an aluminum alloy material for new energy vehicles and a preparation method thereof, so as to solve the problem of low electrical conductivity of the aluminum alloy material.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] In the first aspect, the present invention provides an aluminum alloy material for new energy vehicles, comprising the following components in mass fraction: 0.5-0.6% silicon, 0.95-1.05% magnesium, 0.15-0.25% copper, 0.1-0.2% iron, 0.02-0.025% titanium, 0.05-0.15% chromium, ≤0.15% manganese, ≤0.25% zinc, other unavoidable impurity elements ≤0.1% and the balance aluminum.

[0008] Preferably, the raw materials of the aluminum alloy material include 99.70% high-purity aluminum, 6061 aluminum alloy extrusion white material, industrial pure magnesium, AlSi master alloy, Al-Cu master alloy, aluminum type chromium agent, AlTiB master alloy and AlTiB refiner.

[0009] Preferably, the mass ratio of 99.70% high purity aluminum to 6061 aluminum alloy extrusion white material is (0.2-0.45):(0.55-0.8).

[0010] By adopting the above technical solution, 6061 aluminum alloy is widely used in the field of new energy vehicles, has high strength, can adapt to the load-bearing structure of the vehicle, and also has good processing performance, but the electrical conductivity of 6061 aluminum alloy is poor and is not suitable for electrical applications with high electrical conductivity requirements. Therefore, the present invention optimizes the alloy composition in the aluminum alloy material. Specifically, the present invention adds copper elements. The addition of copper can offset the adverse effects of titanium and iron in the aluminum alloy material on electrical conductivity, and reduce the free impurity elements by forming intermetallic compounds with titanium and iron, thereby reducing the electrical conductivity of the aluminum alloy.

[0011] At the same time, the present invention also appropriately increases the content of alloy elements such as magnesium, silicon and zinc. Magnesium and silicon can be combined with each other and precipitated at the nanometer level during the solid solution aging process. Their ordered structure can significantly reduce the lattice defect density and reduce electron scattering, thereby indirectly improving the conductivity of the material. The addition of zinc can refine the grains and purify the grain boundaries, reduce the impurity segregation at the grain boundaries, thereby reducing the grain boundary resistivity, and zinc can also work together with copper to further optimize the conductive network. At the same time, by appropriately increasing these alloy elements, the strength and corrosion resistance of the alloy can also be improved, and the thermal conductivity of the aluminum alloy can be improved, thereby further improving the stability in practical applications.

[0012] The aluminum substrate used in the present invention is obtained by mixing high-purity aluminum and 6061 aluminum alloy extruded white material. The 6061 aluminum alloy extruded white material refers to the aluminum alloy scraps, cutting residues and recycled old profiles that have not been surface-treated in the extrusion process of the 6061 aluminum alloy during the production process. The high-purity aluminum and the extruded white material are mixed as raw materials, which can greatly reduce resource waste and conform to the development concept of green environmental protection. At the same time, the advantages of high-purity aluminum in electrical conductivity and the advantages of aluminum alloy extruded white material in strength can be combined to obtain an aluminum alloy material with both electrical conductivity and high strength. The addition of high-purity aluminum can reduce the impurity concentration in the mixed system, thereby weakening the negative impact of impurity atoms on electrical conductivity; the extruded white material undergoes plastic deformation during the mixing process to form a high-density dislocation and subgrain structure, and has achieved grain refinement and structural optimization. After mixing, the grain structure with high orientation is inherited by reprocessing, thereby improving the strength of the aluminum alloy material and improving the processing performance of the material.

[0013] Preferably, the raw material includes 0.005-0.01 wt% of rare earth alloy Al-Re.

[0014] By adopting the above technical solution, rare earth alloy Al-Re can also be added in the production process of aluminum alloy. On the one hand, the rare earth element Re can combine with the alloying elements in the aluminum alloy to form a stable high-melting point compound, thereby reducing the solid solution of the alloying elements in the aluminum substrate, and thus improving the conductivity of the aluminum alloy material; on the other hand, the rare earth element will be enriched at the grain boundaries of the aluminum alloy material, reducing the density of defects such as holes and dislocations at the grain boundaries, and at the same time, it can form a nano-precipitated phase between the aluminum substrate, providing heterogeneous nuclear sites without hindering electron migration, thereby improving the conductivity of the material.

[0015] Moreover, the addition of rare earth elements can inhibit grain growth by adsorbing at the solid-liquid interface, thereby refining the grain size and increasing the strength of the obtained aluminum alloy material. It can also improve the corrosion resistance of the aluminum alloy material and obtain a multifunctional aluminum alloy material to meet various performance requirements.

[0016] Preferably, the raw material includes 0.005-0.01 wt% Sc-Zr / TiB 2 Multiphase composite particles; the Sc-Zr / TiB 2 The multiphase composite particles include 1.5-2.5wt% scandium, 1.5-2.5wt% zirconium, TiB 2 45-50wt% and the balance aluminum.

[0017] Preferably, Sc-Zr / TiB 2 The multiphase composite particles were prepared according to the following method:

[0018] Titanium salt and boron salt are mixed with industrial pure aluminum respectively and smelted, and the two melts are mixed after smelting to obtain a mixed melt; scandium oxide and zirconium oxide are added to industrial pure aluminum and mixed and smelted, and then the obtained mixed melt is added, the doping temperature is controlled at 750-850°C, and the mixture is obtained after standing, slag making, degassing and cooling to shape.

[0019] Preferably, the mass ratio of titanium salt to boron salt is (2.1-2.3):1.

[0020] Preferably, the titanium salt is potassium fluorotitanate; and the boron salt is potassium borofluoroate.

[0021] By adopting the above technical solution, Sc-Zr / Ti B 2 Multiphase composite particles are a kind of 2 The invention adds Sc-Zr / TiB in the production process of aluminum alloy material. 2 Multiphase composite particles can further improve the electrical conductivity and mechanical properties of materials, specifically:

[0022] Sc-Zr / Ti B2 TiB in multiphase composite particles 2 It is a kind of conductive ceramic particles. Its particles dispersed in aluminum alloy materials can form a continuous conductive network, thereby reducing the electron transmission path, accelerating the electron migration speed, and significantly improving the conductivity of aluminum alloy materials. At the same time, the introduction of Sc-Zr can form a precipitation phase of aluminum and Sc-Zr, which can purify the grain boundary and reduce the adverse effects of impurity elements. At the same time, it can serve as a nucleation core to refine the grain size of aluminum alloy materials, thereby reducing the grain boundary resistivity. TiB 2 The multiphase composite particles formed by the composite with aluminum matrix also have good compatibility with aluminum alloy materials. 2 Providing a conductive path, Sc-Zr can optimize the electron transmission environment, forming Sc-Zr / TiB 2 Multiphase composite particles can effectively improve the electrical conductivity of aluminum alloy materials.

[0023] Grain boundaries and dislocations are common defects in aluminum alloy materials. Their high density will hinder the conductivity of aluminum alloy materials. The precipitation phase formed by aluminum and Sc-Zr can hinder the movement of dislocations in aluminum alloys, thereby optimizing the conductivity of aluminum alloy materials. 2 Ti B in multiphase composite particles 2 Multiphase composite particles can pin dislocations and crack propagation paths, and Sc-Zr can also reduce TiB 2 The interfacial energy between the particles and the aluminum matrix increases the TiB 2 The dispersion of particles can improve the tensile strength of aluminum alloy materials.

[0024] In a second aspect, the present invention provides a method for preparing an aluminum alloy material for new energy vehicles, comprising the following process steps:

[0025] S1. Melt 99.70% high purity aluminum and 6061 aluminum alloy extrusion white material in a melting furnace, perform the first refining after slagging, and adjust the melt composition by refining. The refining time is 15 to 20 minutes;

[0026] S2. Continue to add industrial pure magnesium, Al-Si master alloy, Al-Cu master alloy and aluminum chromium agent, stir for 30 to 40 minutes for the second refining, the refining time is 15 to 20 minutes;

[0027] S3. The melt is transferred from the converter to the holding furnace and Al TiB master alloy is added for the third refining, the refining time is 30 to 40 minutes; after the composition is qualified, the fourth refining is continued, the refining time is 15 to 20 minutes;

[0028] S4. After refining, the melt is slag-stripped and allowed to stand for 40 to 60 minutes, then cast and refined by adding Al TiB refiner;

[0029] S5. After casting, the obtained cast alloy is homogenized.

[0030] Preferably, in step S3, Sc-Zr / Ti B is added together with the Al TiB master alloy. 2 Multiphase composite particles and / or rare earth alloys Al-Re.

[0031] Preferably, the refining conditions for the first refining, the second refining and the fourth refining are: refining under high-purity argon and adding 0.05-0.075wt% of refining agent; the third refining adopts air-permeable brick refining.

[0032] Preferably, the homogenization process is: keeping warm at 560-580° C. for 6-8 hours.

[0033] By adopting the above technical scheme, the present invention adopts a four-time refining process to accurately adjust the element content in the aluminum alloy, effectively improve the purity and uniformity of the aluminum alloy material, order the atoms in the aluminum alloy material, reduce lattice defects, the introduction of impurity elements and the generation of large-sized grains, thereby achieving improvements in the conductivity, strength and corrosion resistance of the aluminum alloy.

[0034] At the same time, strengthening homogenization treatment after casting can reduce the density of grain boundaries and dislocations in aluminum alloy materials, improve the uniformity and stability of aluminum alloys, help reduce the obstacles of grain boundaries to electron movement, and improve the conductivity of aluminum alloys. Homogenization treatment can also improve the corrosion resistance of aluminum alloys and extend the service life of aluminum alloys.

[0035] Beneficial effects of the present invention:

[0036] 1. The aluminum alloy material for new energy vehicles of the present invention improves the electrical conductivity of the aluminum alloy material from the aspects of optimizing the alloy element content, reducing the density of grain boundaries and dislocations, and strengthening the heat treatment of the material, so as to achieve the improvement of both the electrical conductivity and the mechanical properties. In addition, the aluminum alloy substrate used in the present invention is a mixture of high-purity aluminum and aluminum alloy extrusion white material. The mixture of the two can combine the advantages of high-purity aluminum in electrical conductivity and the advantages of aluminum alloy extrusion white material in strength to obtain an aluminum alloy material with both electrical conductivity and high strength.

[0037] 2. The aluminum alloy material for new energy vehicles of the present invention can be added with a rare earth alloy Al-Re during the production process to reduce the density of defects such as holes and dislocations at the grain boundaries inside the aluminum alloy material, provide heterogeneous nuclear sites without hindering electron migration, and refine the grain size, thereby further improving the conductivity and strength of the aluminum alloy material.

[0038] 3. The aluminum alloy material for new energy vehicles of the present invention can be added with Sc-Zr / TiB during the production process. 2 Multiphase composite particles, TiB 2 Sc-Zr can provide a conductive path for aluminum alloy materials, optimize the electron transmission environment, hinder the dislocation movement in aluminum alloys, optimize the internal structure of aluminum alloy materials, and improve the conductivity and mechanical strength of aluminum alloy materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The present invention will be further described below in conjunction with the accompanying drawings.

[0040] Figure 1 It is a comparison diagram of transmission electron microscope images of Example 1, Example 5, Example 6 and Comparative Example 4 of the present invention. DETAILED DESCRIPTION

[0041] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] Preparation Example

[0043] Preparation Example 1: A Sc-Zr / TiB 2 The multiphase composite particles are prepared according to the following method:

[0044] Potassium fluorotitanate and potassium borofluorate are mixed and smelted with industrial pure aluminum respectively, wherein the mass ratio of potassium fluorotitanate to potassium borofluorate is 2.2:1, and after smelting, the two melts are mixed to obtain a mixed melt; scandium oxide and zirconium oxide are added to industrial pure aluminum for mixed smelting, and then the obtained mixed melt is added, the doping temperature is controlled at 800°C, and the mixture is allowed to stand, slag is formed, degassed and cooled to obtain the mixture;

[0045] The obtained Sc-Zr / TiB 2 The multiphase composite particles contain 2wt% scandium, 2wt% zirconium, TiB 2 45wt% and the balance aluminum.

[0046] Preparation Example 2, a Zr / TiB 2 The multiphase composite particles are different from those in Preparation Example 1 in that scandium oxide is not added. 2 The multiphase composite particles contain 2wt% zirconium, TiB 2 45wt% and the balance aluminum.

[0047] Preparation Example 3, a Sc / TiB 2 The multiphase composite particles are different from those in Preparation Example 1 in that no zirconium oxide is added. 2 The multiphase composite particles contain 2wt% scandium, TiB 2 45wt% and the balance aluminum.

[0048] Preparation Example 3, a TiB 2 The composite particles are prepared according to the following method:

[0049] Potassium fluorotitanate and potassium borofluorate are mixed and smelted with industrial pure aluminum respectively, wherein the mass ratio of potassium fluorotitanate to potassium borofluorate is 2.2:1, and after smelting, the two melts are mixed to obtain a mixed melt; industrial pure aluminum is melted and then added to the obtained mixed melt, the doping temperature is controlled at 800°C, and the mixture is allowed to stand, slag is formed, degassed and cooled to obtain the mixture;

[0050] The obtained TiB 2 The composite particles contain TiB 2 45wt% and aluminum 55wt%.

[0051] Example

[0052] Example 1: An aluminum alloy material for new energy vehicles is prepared according to the following method:

[0053] S1. Melting 99.70% high purity aluminum and 6061 aluminum alloy extrusion white material in a melting furnace, wherein the mass ratio of 99.70% high purity aluminum and 6061 aluminum alloy extrusion white material is 0.4:0.6, and performing the first refining under high purity argon gas conditions after slagging, refining to adjust the melt composition, and adding 0.05wt% refining agent, and the refining time is 15min;

[0054] S2. Continue to put industrial pure magnesium, Al-S i master alloy, Al-Cu master alloy and aluminum chromium agent, stir for 30min, perform a second refining under high purity argon, and add 0.07wt% refining agent, and the refining time is 20min;

[0055] S3. The melt is transferred to a holding furnace and 0.001% Al TiB master alloy is added. The air-permeable brick is opened for the third refining, and the refining time is 40min. After the composition is qualified, the fourth refining is carried out under high-purity argon gas, and 0.05wt% of the refining agent is added, and the refining time is 20min.

[0056] S4. After refining, the melt is slag-stripped and kept at 750°C for 60 minutes, then cast and refined by adding Al Ti B refiner;

[0057] S5. After casting, the obtained cast alloy is homogenized, wherein the homogenization temperature is 570° C. and the treatment time is 7 h.

[0058] The obtained aluminum alloy material for new energy vehicles contains 0.55% silicon, 1% magnesium, 0.2% copper, 0.15% iron, 0.02% titanium, 0.1% chromium, 0.08% manganese, 0.15% zinc, 0.03% other inevitable impurity elements and the balance aluminum.

[0059] Embodiment 2 and Embodiment 3 are aluminum alloy materials for new energy vehicles. The difference from Embodiment 1 is that the alloy element content of the aluminum alloy material is adjusted, as shown in Table 1:

[0060] Table 1 Composition of ingredients of Examples 1 to 3

[0061] silicon magnesium copper iron titanium chromium manganese Zinc Impurities aluminum Example 1 0.55 1 0.2 0.15 0.02 0.1 0.08 0.15 0.03 margin Example 2 0.5 1.05 0.25 0.1 0.02 0.05 0.08 0.15 0.03 margin Example 3 0.6 0.95 0.15 0.2 0.025 0.15 0.08 0.15 0.03 margin

[0062] Example 4, an aluminum alloy material for new energy vehicles, is different from Example 1 only in that the mass ratio of 99.70% high-purity aluminum and 6061 aluminum alloy extrusion white material is 0.4:0.6.

[0063] Example 5, an aluminum alloy material for new energy vehicles, is different from Example 1 only in that the homogenization treatment temperature is 550°C.

[0064] Example 6, an aluminum alloy material for new energy vehicles, is different from Example 1 only in that the homogenization treatment temperature is 590°C.

[0065] Example 7, an aluminum alloy material for new energy vehicles, is different from Example 1 only in that 0.008wt% of rare earth alloy Al-Re is added together with the AlTiB master alloy in step S3.

[0066] Example 8, an aluminum alloy material for new energy vehicles, is different from Example 1 only in that in step S3, 0.008 wt% of Sc-Zr / TiB prepared in Preparation Example 1 is added together with the AlTiB master alloy. 2 Multiphase composite particles.

[0067] Example 9, an aluminum alloy material for new energy vehicles, is different from Example 8 in that an equal amount of Zr / TiB prepared in Example 2 is used. 2 The multiphase composite particles replace the Sc-Zr / TiB prepared in Preparation Example 1. 2 Multiphase composite particles.

[0068] Example 10, an aluminum alloy material for new energy vehicles, is different from Example 8 in that an equal amount of Sc / TiB prepared in Example 3 is used. 2 The multiphase composite particles replace the Sc-Zr / TiB prepared in Preparation Example 1. 2 Multiphase composite particles.

[0069] Example 11, an aluminum alloy material for new energy vehicles, is different from Example 8 in that an equal amount of TiB prepared in Example 4 is used. 2 The composite particles replace the Sc-Zr / TiB prepared in Preparation Example 1. 2 Multiphase composite particles.

[0070] Example 12, an aluminum alloy material for new energy vehicles, is different from Example 8 only in that the Sc-Zr / TiB prepared in Preparation Example 1 is 2 The added amount of the multi-phase composite particles was 0.002 wt%.

[0071] Example 13, an aluminum alloy material for new energy vehicles, is different from Example 8 only in that the Sc-Zr / TiB prepared in Preparation Example 1 is 2 The added amount of the multi-phase composite particles was 0.012 wt%.

[0072] Example 14, an aluminum alloy material for new energy vehicles, is different from Example 1 only in that in step S3, 0.008wt% of rare earth alloy Al-Re and 0.008wt% of Sc-Zr / TiB prepared in Preparation Example 1 are added together with the AlTiB master alloy. 2 Multiphase composite particles.

[0073] Comparative Example

[0074] Comparative Example 1, an aluminum alloy material for new energy vehicles, is different from Example 1 only in that the obtained aluminum alloy material for new energy vehicles contains 0.65% silicon, 0.9% magnesium, 0.3% copper, 0.15% iron, 0.02% titanium, 0.1% chromium, 0.08% manganese, 0.15% zinc, 0.03% other unavoidable impurity elements and the remainder aluminum.

[0075] Comparative Example 2, an aluminum alloy material for new energy vehicles, differs from Example 1 only in that an equal amount of 6061 aluminum alloy extrusion white material is used to replace a mixture of 99.70% high-purity aluminum and 6061 aluminum alloy extrusion white material in a mass ratio of 0.4:0.6.

[0076] Comparative Example 3, an aluminum alloy material for new energy vehicles, differs from Example 1 only in that an equal amount of 99.70% high-purity aluminum is used to replace a mixture of 99.70% high-purity aluminum and 6061 aluminum alloy extrusion white material in a mass ratio of 0.4:0.6.

[0077] Comparative Example 4 is an aluminum alloy material for new energy vehicles, which is different from Example 1 only in that the cast alloy is directly obtained without homogenization treatment.

[0078] Performance testing

[0079] 1. Conductivity test: Take samples of cast alloy and homogenized alloy respectively, and perform conductivity test on the samples according to the relevant records in GB / T 12966-2022 Eddy Current Test Method for Electrical Conductivity of Aluminum and Aluminum Alloys.

[0080] 2. Strength test: According to the relevant records in GB / T 3191-2019 "Aluminum and aluminum alloy extruded bars", the tensile strength of the aluminum alloys obtained in the embodiments and comparative examples at room temperature was tested.

[0081] A control group was set up in both Experiment 1 and Experiment 2, and the samples in the control group were 6061 aluminum alloy bars.

[0082] The above test results are shown in Table 2:

[0083] Table 2 Performance test results

[0084]

[0085] According to Table 2, in combination with Example 1, Example 5, Example 6 and Comparative Example 4, it can be seen that the electrical conductivity and tensile strength of Example 5, Example 6 and Comparative Example 4 are lower than those of Example 1, indicating that the electrical conductivity and mechanical properties of Example 5, Example 6 and Comparative Example 4 are lower than those of Example 1. The reason is that the difference between Example 5, Example 6 and Comparative Example 4 and Example 1 is only that the homogenization process is adjusted. Specifically, the homogenization temperature is lowered in Example 5, so the eutectic structure of the homogenized alloy is not fully dissolved, and the defect density in the aluminum alloy material is increased compared with Example 1, resulting in performance degradation; the homogenization temperature is increased in Example 6, so the grain boundaries of the aluminum alloy have boundary remelting and overburned remelting balls. Figure 1 The grain boundary changes can also be seen in the figure. However, in Comparative Example 4, which has not been homogenized, there are many eutectic structures, the defect density inside the aluminum alloy material is large, the uniformity and stability of the grains are reduced, which is not conducive to the transfer of electrons, thereby causing the conductivity of the grains to decrease.

[0086] Combining Example 1, Example 7, Example 8 and Example 14, it can be seen that the electrical conductivity and tensile strength of Example 7, Example 8 and Example 14 are increased compared with Example 1. The reason is that the difference between Example 7, Example 8 and Example 14 and Example 1 is that Sc-Zr / TiB is added in the production process of the aluminum alloy material. 2 Multiphase composite particles and / or rare earth alloy Al-Re can reduce the density of defects such as holes and dislocations at the grain boundaries of aluminum alloy materials, optimize the internal structure and electron transfer path, and Sc-Zr / TiB 2 The multi-phase composite particles can also provide an additional conductive path, which can significantly improve the conductivity of the material. In Example 14, the two compounds are added at the same time, and the performance improvement is more obvious.

[0087] Combining Example 8 and Example 9 to Example 11, it can be seen that the conductivity and tensile strength of Example 9 to Example 11 are lower than those of Example 8. The reason is that the difference between Example 9 to Example 11 and Example 8 is only the change of TiB 2 The number of composite elements in the particles. If scandium is added alone, a small amount will lead to insignificant improvement, while a large amount will lead to a significant increase in cost, and it will compete and combine with copper in the system, which is not conducive to the optimization of the conductive path; adding zirconium alone will easily lead to lattice distortion, which is not conducive to the improvement of conductivity and strength. Combining the two can form a denser dispersion strengthening network, further refine the grain size, and thus significantly improve the conductivity and strength of the material.

[0088] Combining Example 1 and Comparative Example 1, it can be seen that the electrical conductivity and tensile strength of Comparative Example 1 are lower than those of Example 1. The reason is that Comparative Example 1 adopts the alloy element content combination of conventional 6061 aluminum alloy, which has a significantly lower effect on the lattice defect density than Example 1, and the conductivity is reduced.

[0089] In combination with Example 1, Comparative Example 2 and Comparative Example 3, it can be seen that the electrical conductivity and tensile strength of Comparative Example 2 and Comparative Example 3 are lower than those of Example 1. The reason is that in Comparative Example 2 and Comparative Example 3, a mixture of high-purity aluminum and aluminum alloy extrusion white material is not used. If high-purity aluminum is added alone, the strength is insufficient, and if aluminum alloy extrusion white material is added alone, the strength of the material is insufficient, and it is difficult to obtain an aluminum alloy material with both conductivity and strength.

[0090] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0091] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An aluminum alloy material for new energy vehicles, characterized in that: The invention comprises the following components in mass fraction: silicon 0.5-0.6%, magnesium 0.95-1.05%, copper 0.15-0.25%, iron 0.1-0.2%, titanium 0.02-0.025%, chromium 0.05-0.15%, manganese ≤0.15%, zinc ≤0.25%, other unavoidable impurity elements ≤0.1% and the balance aluminum.

2. The aluminum alloy material for new energy vehicles according to claim 1, characterized in that: The raw materials of the aluminum alloy material include 99.70% high-purity aluminum, 6061 aluminum alloy extrusion white material, industrial pure magnesium, Al-Si master alloy, Al-Cu master alloy, aluminum type chromium agent, AlTiB master alloy and AlTiB refiner.

3. The aluminum alloy material for new energy vehicles according to claim 2, characterized in that: The mass ratio of the 99.70% high-purity aluminum to the 6061 aluminum alloy extrusion white material is (0.2-0.45): (0.55-0.8).

4. The aluminum alloy material for new energy vehicles according to claim 2, characterized in that: The raw material includes 0.005-0.01wt% of rare earth alloy Al-Re.

5. The aluminum alloy material for new energy vehicles according to claim 2, characterized in that: The raw material includes 0.005-0.01wt% of Sc-Zr / TiB2 multiphase composite particles; the Sc-Zr / TiB2 multiphase composite particles include 1.5-2.5wt% of scandium, 1.5-2.5wt% of zirconium, 45-50wt% of TiB2 and the balance of aluminum.

6. The aluminum alloy material for new energy vehicles according to claim 5, characterized in that: The Sc-Zr / TiB2 multiphase composite particles are prepared according to the following method: Titanium salt and boron salt are mixed with industrial pure aluminum respectively and smelted, and the two melts are mixed after smelting to obtain a mixed melt; scandium oxide and zirconium oxide are added to industrial pure aluminum and mixed and smelted, and then the obtained mixed melt is added, the doping temperature is controlled at 750-850°C, and the mixture is obtained after standing, slag making, degassing and cooling to shape.

7. A method for preparing an aluminum alloy material for new energy vehicles according to any one of claims 1 to 6, characterized in that: The process steps include: S1. Melt 99.70% high purity aluminum and 6061 aluminum alloy extrusion white material in a melting furnace, perform the first refining after slagging, and adjust the melt composition by refining. The refining time is 15 to 20 minutes; S2. Continue to add industrial pure magnesium, Al-Si master alloy, Al-Cu master alloy and aluminum chromium agent, stir for 30 to 40 minutes for the second refining, and the refining time is 15 to 20 minutes; S3. The melt is transferred from the converter to the holding furnace and AlTiB master alloy is added for the third refining, the refining time is 30 to 40 minutes; after the composition is qualified, the fourth refining is continued, the refining time is 15 to 20 minutes; S4. After refining, the melt is slag-stripped and allowed to stand for 40 to 60 minutes, then cast and refined by adding AlTiB refiner; S5. After casting, the obtained cast alloy is homogenized.

8. The method for preparing the aluminum alloy material for new energy vehicles according to claim 7, characterized in that: In the step S3, Sc-Zr / TiB2 multiphase composite particles and / or rare earth alloy Al-Re are added together with the AlTiB master alloy.

9. The method for preparing the aluminum alloy material for new energy vehicles according to claim 7, characterized in that: The refining conditions for the first refining, the second refining and the fourth refining are: refining is carried out under high-purity argon and 0.05-0.075wt% of refining agent is added; the third refining adopts air-permeable brick refining.

10. The method for preparing an aluminum alloy material for new energy vehicles according to claim 7, characterized in that: The homogenization process is: keeping the temperature at 560-580° C. for 6-8 hours.

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