Aluminum alloy material and preparation method thereof

Abstract

The invention relates to an aluminum alloy material and a preparation method thereof. Based on the total weight of the aluminum alloy material, the aluminum alloy material comprises the following components in percentage by weight: 8.5 wt% to 9.3 wt% of Si; from 0.78 wt% to 0.83 wt% of Fe; from 0.46 wt% to 0.54 wt% of Mg; from 0.025 wt% to 0.04 wt% of Sr; the aluminum alloy material comprises the following components in percentage by weight: 0.01 wt%-0.1 wt% of B, 0.01 wt%-0.1 wt% of La and the balance of Al and inevitable impurity elements, or 0.01 wt% to 0.1 wt% of B and 0.01 wt% to 0.1 wt% of Ce; or 0.01 wt% to 0.1 wt% of Ti, 0.1 wt% to 1 wt% of C, and 0.01 wt% to 0.1 wt% of Sc. The aluminum alloy material has excellent formability, mechanical property and heat-conducting property, the size can be uniformly changed in the interference assembly process, and the maximum deformation is low after interference assembly.

Description

Technical Field

[0001] The present invention relates to the field of casting technology, and in particular to an aluminum alloy material and a preparation method thereof, and more particularly to a high thermal conductivity die-casting aluminum alloy material and a method for preparing the aluminum alloy material. Background Art

[0002] High thermal conductivity die-cast aluminum alloy materials can be widely used in many fields such as 5G communications, 3C electronics, and new energy vehicles. Due to the different structural designs, assembly conditions, and service environments of the corresponding parts, the comprehensive performance requirements of the corresponding parts are also different. For example, when used as a material for the motor housing of new energy vehicles, as the integration of motors and the operating power density become higher and higher, aluminum alloy materials are required to have higher thermal conductivity and mechanical properties while ensuring the smooth forming of parts. At the same time, since the subsequent assembly process of the motor housing is achieved through heating expansion and interference assembly with the stator, in order to ensure that the stator can be installed smoothly, the aluminum alloy material is also required to achieve the expected diameter expansion during the heating process and maintain uniform roundness to minimize deformation behavior. Die-cast aluminum alloy materials such as ADC12 have excellent forming and mechanical properties, but low thermal conductivity, with a thermal conductivity coefficient of only 90-120W / m·K, while conventional high thermal conductivity aluminum alloy materials mainly improve thermal conductivity through melt purification treatment, and have poor forming and mechanical properties. In addition, studies have shown that existing aluminum alloy materials will undergo varying degrees of deformation as the temperature increases during the interference fit process, which will not only increase the assembly cost, but will also generate motor vibration noise during the subsequent motor service life, affecting the motor's service life and driving experience.

[0003] Therefore, it is necessary to develop a new aluminum alloy material and a method for preparing the aluminum alloy material to meet the comprehensive performance requirements such as forming performance, mechanical properties, thermal conductivity, and uniform and controllable dimensional changes during interference fitting. Summary of the invention

[0004] The purpose of the present invention is to provide an aluminum alloy material and a method for preparing the aluminum alloy material, so as to solve the technical problem that the aluminum alloy material in the prior art cannot simultaneously take into account the comprehensive performance requirements such as forming performance, mechanical properties, thermal conductivity, and uniform and controllable dimensional changes during interference fitting.

[0005] To achieve the above-mentioned purpose, according to one aspect of the present invention, there is provided an aluminum alloy material, which comprises, based on the total weight of the aluminum alloy material, the following in weight percentage: 8.5wt% to 9.3wt% Si; 0.78wt% to 0.83wt% Fe; 0.46wt% to 0.54wt% Mg; 0.025wt% to 0.04wt% Sr; and the remainder of Al and unavoidable impurity elements, wherein the aluminum alloy material further comprises: 0.01wt% to 0.1wt% B and 0.01wt% to 0.1wt% La; or 0.01wt% to 0.1wt% B and 0.01wt% to 0.1wt% Ce; or 0.01wt% to 0.1wt% Ti, 0.1wt% to 1wt% C and 0.01wt% to 0.1wt% Sc.

[0006] Furthermore, among the inevitable impurity elements, Cu≤0.005wt%, Zn≤0.01wt%, Mn≤0.01wt%, Cr≤0.01wt% and V≤0.01wt%.

[0007] According to another aspect of the present invention, a method for preparing the aluminum alloy material described above is provided, the method comprising the following steps: step S1: adding pure aluminum and pure silicon or aluminum-silicon master alloy into a smelting furnace, heating to 740° C. to 780° C. to obtain a first melt; step S2: adding aluminum-iron master alloy or iron agent to the first melt, stirring and mixing, to obtain a second melt; step S3: lowering the temperature of the second melt to 720° C. to 740° C., adding pure magnesium, stirring and mixing, to obtain a third melt; step S4: adding aluminum-strontium master alloy to the third melt, stirring and mixing, to obtain a fourth melt; step S5: adding Al-La-B master alloy, Al-Ce-B master alloy or Al-Ti-C to the fourth melt; -Sc intermediate alloy, stirring and mixing to obtain a first aluminum alloy melt; step S6: performing component detection on the first aluminum alloy melt, after the component is qualified, using nitrogen or inert gas as a carrier to blow a refining agent into the first aluminum alloy melt for refining and degassing, and then removing slag and standing to obtain a second aluminum alloy melt; step S7: transferring the second aluminum alloy melt to a machine-side furnace of a die-casting machine, and performing die-casting after standing to obtain a die-casting, wherein the temperature of the machine-side furnace is controlled at 670°C to 685°C, the temperature of the mold during the die-casting process is controlled at 150°C to 200°C, and the die-casting speed is controlled at 4.5m / s to 6.0m / s; and step S8: cooling the die-casting, and then performing aging treatment to obtain the aluminum alloy material.

[0008] Furthermore, in the Al-La-B master alloy, the content of La is 1wt% to 10wt%, and the content of B is 5wt% to 20wt%.

[0009] Furthermore, in the Al-Ce-B master alloy, the content of Ce is 1wt% to 10wt%, and the content of B is 5wt% to 20wt%.

[0010] Furthermore, in the Al-Ti-C-Sc master alloy, the content of Ti is 1wt% to 10wt%, the content of C is 5wt% to 20wt%, and the content of Sc is 1wt% to 10wt%.

[0011] Furthermore, in the step S5, the addition amount of the Al-La-B master alloy, the Al-Ce-B master alloy or the Al-Ti-C-Sc master alloy accounts for 0.1wt% to 1wt% of the total weight of the aluminum alloy material.

[0012] Furthermore, in the step S8, the temperature of the aging treatment is 250° C. to 300° C., and the time of the aging treatment is 0.5 h to 2 h.

[0013] Furthermore, in step S7, vacuum die-casting is used for die-casting, and during the vacuum die-casting process, the vacuum degree is controlled below 100 mbar.

[0014] Furthermore, the bulk yield strength of the aluminum alloy material is ≥190 MPa, the thermal conductivity is ≥165 W / m·K, and the maximum deformation after interference fitting is controlled within the range of 0.1 mm to 0.5 mm.

[0015] The present invention introduces Al-La-B master alloy, Al-Ce-B master alloy or Al-Ti-C-Sc master alloy through comprehensive alloy component design, improves the poisoning behavior caused by simultaneous addition of Sr and B or simultaneous addition of Sc and Ti-B, and achieves the balance of forming performance, mechanical properties and thermal conductivity; at the same time, AlSiLa, AlSiCe or Al3(Sc) is precipitated in the alloy microstructure. 1-x Ti x) and other fine compound phases, combined with the adjustment of the die-casting temperature, mold temperature and die-casting speed in the die-casting process, it is possible to achieve uniform size changes during the interference fitting process and control the maximum deformation after the interference fitting. The aluminum alloy material of the present invention has excellent forming properties, mechanical properties and thermal conductivity, and can achieve uniform size changes during the interference fitting process and have a lower maximum deformation after the interference fitting. The method for preparing the aluminum alloy material of the present invention has a simple overall process and controllable production cost. It is suitable for large-scale batch production, and is particularly suitable for the production of aluminum alloy materials with a wall thickness of 1mm to 5mm. The bulk yield strength of the aluminum alloy material is ≥190MPa, the thermal conductivity is ≥165W / m·K, and the maximum deformation after the interference fitting can be controlled within the range of 0.1mm to 0.5mm. DETAILED DESCRIPTION

[0016] It should be noted that, in the absence of conflict, the various embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below in conjunction with the embodiments. The following embodiments are merely exemplary and are not intended to limit the scope of protection of the present invention.

[0017] As described in the background of the present invention, the aluminum alloy materials in the prior art cannot simultaneously meet the comprehensive performance requirements such as forming performance, mechanical properties, thermal conductivity, and uniform and controllable dimensional changes during interference fitting.

[0018] In order to solve the above problems in the prior art, the applicant has conducted a lot of research. From the perspective of materials, aluminum alloy materials need to add sufficient amounts of key elements such as Si and Fe to ensure smooth forming and demolding of parts; on this basis, in order to improve the mechanical properties, Mg elements can be added to form a strengthening phase, or Al-Ti-B, Al-Ti-C, Al-Ti-CB and other substances can be added to achieve fine grain strengthening; and in order to improve thermal conductivity, it is necessary to increase the purity of the matrix as much as possible, and strictly control the addition of each element. At the same time, considering that the silicon phase as the main precipitated phase is a poor conductor of heat and has a coarse lamellar structure, the silicon phase must also be modified. The modification method of eutectic alloys can be Sr modification, which has a long effective period and has a remelting modification effect. In addition, the addition of rare earth elements in aluminum alloy materials can also refine the grains and improve thermal conductivity and mechanical properties.

[0019] However, when the material is required to take into account these comprehensive properties, it is not possible to obtain a beneficial effect of one plus one greater than two simply by adding all the favorable factors. For example, Ti atoms in the melt are easily enriched with B to form TiB2 particles, which can serve as heterogeneous nucleation to refine the grains, but Sr will react with B to form SrB6 compounds, causing Ti atoms to dissolve into the aluminum matrix, increasing the degree of lattice distortion and affecting the thermal conductivity of the material. For another example, when Sc elements and Ti-B exist simultaneously in the melt, poisoning will also occur in the nucleation stage of the grains, and the refining effect of Sc and Ti-B cannot be reflected.

[0020] In addition, it is necessary to ensure that the dimensional changes of the material during the interference fit process are uniform and controllable. It is necessary not only to ensure that the alloy solidification structure is uniform and dense, without quality defects such as shrinkage and shrinkage holes, and reduce the expansion amount generated by filling the pores during the heating process; but also to be able to form a uniformly distributed and finely shaped high-temperature stable phase, hinder dislocation recovery during the heating process of the parts, increase the internal stress of the material, thereby increasing the atomic energy, increasing the thermal expansion coefficient, and reducing the maximum deformation after the interference fit.

[0021] After a large number of experimental studies, the applicant first determined that the aluminum alloy material contains 8.5wt% to 9.3wt% Si, 0.78wt% to 0.83wt% Fe, 0.46wt% to 0.54wt% Mg, and 0.025wt% to 0.04wt% Sr as the main alloy components based on the total weight of the aluminum alloy material. On this basis, in order to further optimize the comprehensive performance and ensure that the dimensional change is uniform and controllable during the interference assembly process, the aluminum alloy material further contains 0.01wt% to 0.1wt% B and 0.01wt% to 0.1wt% La; or 0.01wt% to 0.1wt% B and 0.01wt% to 0.1wt% Ce; or 0.01wt% to 0.1wt% Ti, 0.1wt% to 1wt% C, and 0.01wt% to 0.1wt% Sc. The rest is Al and inevitable impurity elements. The present invention forms AlSiLa, AlSiCe, Al3(Sc 1-x Ti x ) and other fine compound phases, combined with the adjustment of die-casting temperature, mold temperature and die-casting speed in the die-casting process, the size can be uniformly changed during the interference fitting process, and the maximum deformation after interference fitting can be controlled within the range of 0.1mm to 0.5mm.

[0022] That is, in order to solve the problems in the prior art, a typical embodiment of the present invention provides an aluminum alloy material, which, based on the total weight of the aluminum alloy material, contains, by weight percentage: 8.5wt% to 9.3wt% Si; 0.78wt% to 0.83wt% Fe; 0.46wt% to 0.54wt% Mg; 0.025wt% to 0.04wt% Sr; and the remainder of Al and unavoidable impurity elements, wherein the aluminum alloy material also contains: 0.01wt% to 0.1wt% B and 0.01wt% to 0.1wt% La; or 0.01wt% to 0.1wt% B and 0.01wt% to 0.1wt% Ce; or 0.01wt% to 0.1wt% Ti, 0.1wt% to 1wt% C and 0.01wt% to 0.1wt% Sc.

[0023] The present invention introduces Al-La-B master alloy, Al-Ce-B master alloy or Al-Ti-C-Sc master alloy through comprehensive alloy component design, improves the poisoning behavior caused by simultaneous addition of Sr and B or simultaneous addition of Sc and Ti-B, and achieves the balance of forming performance, mechanical properties and thermal conductivity; at the same time, AlSiLa, AlSiCe or Al3(Sc) is precipitated in the alloy microstructure. 1-x Ti x ) and other fine compound phases, which can achieve uniform size change during interference fitting and control the maximum deformation after interference fitting. The aluminum alloy material of the present invention has excellent forming performance, mechanical properties and thermal conductivity, can achieve uniform size change during interference fitting and have a lower maximum deformation after interference fitting.

[0024] In some embodiments of the present invention, the aluminum alloy material comprises, by weight percentage, 8.5wt%, 8.6wt%, 8.7wt%, 8.8wt%, 8.9wt%, 9.0wt%, 9.1wt%, 9.2wt%, or 9.3wt% Si; 0.78wt%, 0.79wt%, 0.80wt%, 0.81wt%, 0.82wt%, or 0.83wt% Fe; 0.46wt%, 0.47wt%, 0.48wt%, 0.49wt%, 0.50wt%, 0.51wt%, 0.52wt%, 0.53wt%, or 0.54wt% Mg; 0.025wt%, 0.027wt%, 0.030wt%, 0.031wt%, 0.032wt%, 0.033wt%, 0.034wt%, 0.035wt%, 0.036wt%, 0.037wt%, 0.038wt%, 0.039wt%, 0.040wt%, 0.041wt%, 0.042wt%, 0.043wt%, 0.044wt%, 0.045wt%, 0.046wt%, 0.047wt%, 0.048wt%, 0.049wt%, 0.050wt%, 0.051wt%, 0.052wt%, 0.053wt%, 0.054wt%, 0.055wt%, 0.056wt%, 0.057wt%, 0.058wt%, 0.061wt%, 0.062wt%, 0.063wt%, 0.064wt%, 0.065wt%, 0.066wt%, 0.067wt%, 0.068wt%, 0.069wt%, %, 0.02wt%, 0.03wt%, 0.04wt%, 0.05wt%, 0.06wt%, 0.07wt%, 0.08wt%, 0.09wt%, or 0.1wt% of B; 0.01wt%, 0.02wt%, 0.03wt%, 0.04wt%, 0.05wt%, 0.06wt%, 0.07wt%, 0.08wt%, 0.09wt%, or 0.1wt% of La; and the remainder of Al and inevitable impurity elements.

[0025] In some embodiments of the present invention, the aluminum alloy material comprises, by weight percentage, 8.5wt%, 8.6wt%, 8.7wt%, 8.8wt%, 8.9wt%, 9.0wt%, 9.1wt%, 9.2wt%, or 9.3wt% Si; 0.78wt%, 0.79wt%, 0.80wt%, 0.81wt%, 0.82wt%, or 0.83wt% Fe; 0.46wt%, 0.47wt%, 0.48wt%, 0.49wt%, 0.50wt%, 0.51wt%, 0.52wt%, 0.53wt%, or 0.54wt% Mg; 0.025wt%, 0.027wt%, 0.030wt%, 0.031wt%, 0.032wt%, 0.033wt%, 0.034wt%, 0.035wt%, 0.036wt%, 0.037wt%, 0.038wt%, 0.039wt%, 0.040wt%, 0.041wt%, 0.042wt%, 0.043wt%, 0.044wt%, 0.045wt%, 0.046wt%, 0.047wt%, 0.048wt%, 0.049wt%, 0.050wt%, 0.051wt%, 0.052wt%, 0.053wt%, 0.054wt%, 0.055wt%, 0.056wt%, 0.057wt%, 0.058wt%, 0.061wt%, 0.062wt%, 0.063wt%, 0.064wt%, 0.065wt%, 0.066wt%, 0.067wt%, 0.068wt%, 0.069wt%, %, 0.02wt%, 0.03wt%, 0.04wt%, 0.05wt%, 0.06wt%, 0.07wt%, 0.08wt%, 0.09wt%, or 0.1wt% of B; 0.01wt%, 0.02wt%, 0.03wt%, 0.04wt%, 0.05wt%, 0.06wt%, 0.07wt%, 0.08wt%, 0.09wt%, or 0.1wt% of Ce; and the remainder of Al and unavoidable impurity elements.

[0026] In some embodiments of the present invention, the aluminum alloy material comprises, by weight percentage, 8.5wt%, 8.6wt%, 8.7wt%, 8.8wt%, 8.9wt%, 9.0wt%, 9.1wt%, 9.2wt%, or 9.3wt% Si; 0.78wt%, 0.79wt%, 0.80wt%, 0.81wt%, 0.82wt%, or 0.83wt% Fe; 0.46wt%, 0.47wt%, 0.48wt%, 0.49wt%, 0.50wt%, 0.51wt%, 0.52wt%, 0.53wt%, or 0.54wt% Mg; 0.025wt%, 0.027wt%, 0.029wt%, 0.031wt%, 0.033wt%, 0.035wt% %, 0.037wt%, 0.039wt%, or 0.04wt% Sr; 0.01wt%, 0.02wt%, 0.03wt%, 0.04wt%, 0.05wt%, 0.06wt%, 0.07wt%, 0.08wt%, 0.09wt%, or 0.1wt% Ti; 0.1wt%, 0.2wt%, 0.3wt%, 0.4wt%, 0.5wt%, 0.6wt%, 0.7wt%, 0.8wt%, 0.9wt%, or 1wt% C; 0.01wt%, 0.02wt%, 0.03wt%, 0.04wt%, 0.05wt%, 0.06wt%, 0.07wt%, 0.08wt%, 0.09wt%, or 0.1wt% Sc; and the remainder of Al and unavoidable impurity elements.

[0027] In some embodiments of the present invention, among the inevitable impurity elements, the content of each impurity element is ≤0.01wt%, and the total of all impurity elements is ≤0.2wt%. In some embodiments of the present invention, among the inevitable impurity elements, Cu≤0.005wt%, Zn≤0.01wt%, Mn≤0.01wt%, Cr≤0.01wt% and V≤0.01wt%. By controlling the content of impurity elements within the above range, it is helpful to improve the forming performance, mechanical properties and thermal conductivity of aluminum alloy materials.

[0028] Another typical embodiment of the present invention provides a method for preparing the aluminum alloy material described above, the method comprising the following steps: step S1: adding pure aluminum and pure silicon or aluminum-silicon master alloy into a smelting furnace, heating to 740°C to 780°C to obtain a first melt; step S2: adding aluminum-iron master alloy or iron agent to the first melt, stirring and mixing, to obtain a second melt; step S3: lowering the temperature of the second melt to 720°C to 740°C, adding pure magnesium, stirring and mixing, to obtain a third melt; step S4: adding aluminum-strontium master alloy to the third melt, stirring and mixing, to obtain a fourth melt; step S5: adding Al-La-B master alloy, Al-Ce-B master alloy or Al-Ti-C-S to the fourth melt. c intermediate alloy, stirring and mixing to obtain a first aluminum alloy melt; step S6: performing component detection on the first aluminum alloy melt, after the component is qualified, using nitrogen or inert gas as a carrier to blow a refining agent into the first aluminum alloy melt for refining and degassing, and then removing slag and standing to obtain a second aluminum alloy melt; step S7: transferring the second aluminum alloy melt to a machine-side furnace of a die-casting machine, and performing die-casting after standing to obtain a die-casting, wherein the temperature of the machine-side furnace is controlled at 670°C to 685°C, the temperature of the mold during the die-casting process is controlled at 150°C to 200°C, and the die-casting speed is controlled at 4.5m / s to 6.0m / s; and step S8: cooling the die-casting, for example, naturally cooling, and then performing aging treatment to obtain an aluminum alloy material.

[0029] The present invention introduces Al-La-B master alloy, Al-Ce-B master alloy or Al-Ti-C-Sc master alloy through comprehensive alloy component design, improves the poisoning behavior caused by simultaneous addition of Sr and B or simultaneous addition of Sc and Ti-B, and achieves the balance of forming performance, mechanical properties and thermal conductivity; at the same time, AlSiLa, AlSiCe or Al3(Sc) is precipitated in the alloy microstructure. 1-x Ti x ) and other fine compound phases, combined with the adjustment of the die-casting temperature, mold temperature and die-casting speed in the die-casting process, it is possible to achieve uniform size changes during the interference fitting process and control the maximum deformation after the interference fitting. The aluminum alloy material prepared by the method of the present invention has excellent forming properties, mechanical properties and thermal conductivity, and can achieve uniform size changes during the interference fitting process and has a lower maximum deformation after the interference fitting. The method for preparing aluminum alloy materials of the present invention has a simple overall process and controllable production costs. It is suitable for large-scale batch production, and is particularly suitable for the production of aluminum alloy materials with a wall thickness of 1mm to 5mm. The bulk yield strength of the aluminum alloy material is ≥190MPa, the thermal conductivity is ≥165W / m·K, and the maximum deformation after the interference fitting can be controlled within the range of 0.1mm to 0.5mm.

[0030] In some embodiments of the present invention, in the above method for preparing an aluminum alloy material, in the Al-La-B master alloy, the content of La is 1wt% to 10wt%, and the content of B is 5wt% to 20wt%. Specifically, in the Al-La-B master alloy, the content of La can be 2wt% to 9wt%, 3wt% to 8wt%, 4wt% to 7wt%, or 5wt% to 6wt%; the content of B can be 7wt% to 18wt%, 9wt% to 16wt%, 11wt% to 14wt%, or 12wt% to 13wt%. By controlling the contents of La and B in the Al-La-B master alloy within the above range, it is helpful to improve the forming performance, mechanical properties and thermal conductivity of the aluminum alloy material prepared by the method of the present invention, and it is helpful to achieve uniform size change of the aluminum alloy material during the interference fitting process and to control the maximum deformation of the aluminum alloy material after the interference fitting.

[0031] In some embodiments of the present invention, in the above method for preparing an aluminum alloy material, in the Al-Ce-B master alloy, the content of Ce is 1wt% to 10wt%, and the content of B is 5wt% to 20wt%. Specifically, in the Al-Ce-B master alloy, the content of Ce can be 2wt% to 9wt%, 3wt% to 8wt%, 4wt% to 7wt%, or 5wt% to 6wt%; the content of B can be 7wt% to 18wt%, 9wt% to 16wt%, 11wt% to 14wt%, or 12wt% to 13wt%. By controlling the contents of Ce and B in the Al-Ce-B master alloy within the above range, it is helpful to improve the forming performance, mechanical properties and thermal conductivity of the aluminum alloy material prepared by the method of the present invention, and to achieve uniform size change of the aluminum alloy material during interference fitting and to control the maximum deformation of the aluminum alloy material after interference fitting.

[0032] In some embodiments of the present invention, in the above method for preparing an aluminum alloy material, in the Al-Ti-C-Sc master alloy, the content of Ti is 1wt% to 10wt%, the content of C is 5wt% to 20wt%, and the content of Sc is 1wt% to 10wt%. Specifically, in the Al-Ti-C-Sc master alloy, the content of Ti can be 2wt% to 9wt%, 3wt% to 8wt%, 4wt% to 7wt%, or 5wt% to 6wt%; the content of C can be 7wt% to 18wt%, 9wt% to 16wt%, 11wt% to 14wt%, or 12wt% to 13wt%; the content of Sc can be 2wt% to 9wt%, 3wt% to 8wt%, 4wt% to 7wt%, or 5wt% to 6wt%. By controlling the contents of Ti, C and Sc in the Al-Ti-C-Sc master alloy within the above range, it helps to improve the forming performance, mechanical properties and thermal conductivity of the aluminum alloy material prepared by the method of the present invention, helps to achieve uniform dimensional changes of the aluminum alloy material during the interference fitting process, and helps to control the maximum deformation of the aluminum alloy material after interference fitting.

[0033] In some embodiments of the present invention, in the above method for preparing aluminum alloy material, in step S5, the addition amount of Al-La-B master alloy, Al-Ce-B master alloy or Al-Ti-C-Sc master alloy accounts for 0.1wt% to 1wt% of the total weight of the aluminum alloy material, for example, 0.2wt% to 0.9wt%, 0.3wt% to 0.8wt%, 0.4wt% to 0.7wt%, or 0.5wt% to 0.6wt% of the total weight of the aluminum alloy material. By controlling the addition amount of Al-La-B master alloy, Al-Ce-B master alloy or Al-Ti-C-Sc master alloy within the above range, it is helpful to improve the forming performance, mechanical properties and thermal conductivity of the aluminum alloy material prepared by the method of the present invention, and to achieve uniform size change of the aluminum alloy material during interference fitting and to control the maximum deformation of the aluminum alloy material after interference fitting.

[0034] In some embodiments of the present invention, in the above method for preparing an aluminum alloy material, in step S8, the temperature of the aging treatment is 250° C. to 300° C., and the time of the aging treatment is 0.5 h to 2 h. By controlling the temperature and time of the aging treatment in step S8 within the above range, it is helpful to optimize the solidification structure of the aluminum alloy material, improve the dimensional stability of the aluminum alloy material, and improve the mechanical properties and corrosion resistance of the aluminum alloy material.

[0035] In some embodiments of the present invention, in the above method for preparing an aluminum alloy material, vacuum die casting is performed in step S7, and during the vacuum die casting process, the vacuum degree is controlled to be below 100 mbar. The vacuum die casting can improve the filling performance, ensure that there are no defects such as shrinkage and shrinkage cavities inside the aluminum alloy material, and improve the mechanical properties and surface quality of the aluminum alloy material.

[0036] The pure silicon in the present invention can be, for example, quick-dissolving silicon. The aluminum-silicon master alloy in the present invention can be, for example, Al-20Si master alloy or Al-50Si master alloy. In some embodiments of the present invention, the iron content in the aluminum-iron master alloy can be, for example, in the range of 5wt% to 25wt%. The aluminum-iron master alloy in the present invention can be, for example, Al-5Fe master alloy or Al-10Fe master alloy or Al-20Fe master alloy. The aluminum-strontium master alloy in the present invention can be, for example, Al-10Sr master alloy. In some embodiments of the present invention, the iron content in the iron agent can be, for example, in the range of 75wt% to 90wt%.

[0037] In some embodiments of the present invention, in the above method for preparing aluminum alloy material, in step S6, the inert gas may be, for example, argon. In some embodiments of the present invention, in order to improve the degassing and refining effect and improve the performance of the aluminum alloy material, in step S6, the first aluminum alloy melt is subjected to component detection, and after the component is qualified, a refining agent is blown into the first aluminum alloy melt using nitrogen or an inert gas as a carrier for refining and degassing, the degassing time is 5min-15min, and then the slag is removed and left to stand for 5min-15min to obtain a second aluminum alloy melt.

[0038] In some embodiments of the present invention, the bulk yield strength of the aluminum alloy material is ≥190 MPa, the thermal conductivity is ≥165 W / m·K, and the maximum deformation after interference fitting is controlled within the range of 0.1 mm to 0.5 mm.

[0039] In some embodiments of the present invention, in the above method for preparing an aluminum alloy material, in step S7, the standing time may be 5 min-15 min, preferably 7 min-13 min, more preferably 8 min-12 min, and further preferably 10 min-11 min.

[0040] The aluminum alloy material of the present invention can be used, for example, as heat dissipation parts such as die-cast housings, blind hole housings, and water-cooled housings for new energy vehicles that require interference fitting and have high requirements for thermal conductivity and mechanical properties.

[0041] The present application is further described in detail below in conjunction with specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed in the present application.

[0042] Example 1

[0043] An aluminum alloy material is prepared according to the following steps. The aluminum alloy material comprises, based on the total weight of the aluminum alloy material, 8.5wt% Si, 0.8wt% Fe, 0.46wt% Mg, 0.025wt% Sr, 0.02wt% B, 0.01wt% La, the remainder Al and inevitable impurity elements, wherein the inevitable impurity elements include 0.005wt% Cu, 0.01wt% Zn, 0.002wt% Mn, 0.001wt% Cr and 0.007wt%.

[0044] Step S1: putting an aluminum ingot (99.7%) weighed according to the above alloy composition and quick-dissolving silicon into a smelting furnace, heating to 750° C. until they are completely melted;

[0045] Step S2: adding weighed Al-10Fe master alloy to the melt obtained in step S1, and stirring and mixing;

[0046] Step S3: lowering the temperature of the melt obtained in step S2 to 730° C., adding weighed magnesium ingot (99.9%), and stirring and mixing;

[0047] Step S4: adding weighed Al-10Sr master alloy to the melt obtained in step S3, stirring and mixing, and keeping warm for 10 minutes;

[0048] Step S5: adding weighed Al-La-B master alloy to the melt obtained in step S4 and stirring for 5 minutes;

[0049] Step S6: testing the composition of the aluminum alloy melt obtained in step S5. After the composition is qualified, nitrogen is used as a carrier to blow a sodium-free refining agent into the aluminum alloy melt for refining and degassing. The degassing time is 15 minutes, and then the slag is removed and left to stand for 15 minutes.

[0050] Step S7: The aluminum alloy melt obtained in step S6 is transferred to a side furnace of a die-casting machine, the temperature of the side furnace is controlled at 670° C., and die-casting is started after standing for 10 minutes. During the die-casting process, the temperature of the mold is controlled at 150° C., the die-casting speed is controlled at 4.5 m / s, and the vacuum degree is controlled at about 80 mbar;

[0051] Step S8: The die casting obtained in step S7 is naturally cooled, and then subjected to a short-time aging treatment, wherein the aging treatment temperature is 300° C. and the aging treatment time is 0.5 h.

[0052] The die casting obtained in step S8 is fully filled. After sampling the die casting body, the yield strength of the body is measured to be 195 MPa, the thermal conductivity is 178 W / m·K, the size changes evenly during the interference fit process, and the maximum deformation after the interference fit is 0.45 mm.

[0053] Example 2

[0054] An aluminum alloy material is prepared according to the following steps. The aluminum alloy material comprises, based on the total weight of the aluminum alloy material, 9.0wt% Si, 0.83wt% Fe, 0.5wt% Mg, 0.04wt% Sr, 0.01wt% Ce, 0.02wt% B, the remainder Al and inevitable impurity elements, wherein the inevitable impurity elements include 0.005wt% Cu, 0.01wt% Zn, 0.002wt% Mn, 0.001wt% Cr, 0.007wt% V and 0.001wt% Ti.

[0055] Step S1: putting the aluminum ingot (99.7%) weighed according to the above alloy composition and the Al-20Si master alloy into a melting furnace, heating to 780° C. until they are completely melted;

[0056] Step S2: adding weighed Fe agent to the melt obtained in step S1, stirring and mixing, and keeping warm for 15 minutes;

[0057] Step S3: lowering the temperature of the melt obtained in step S2 to 740° C., adding weighed magnesium ingot (99.9%), and stirring and mixing;

[0058] Step S4: adding weighed Al-10Sr master alloy to the melt obtained in step S3, and stirring and mixing;

[0059] Step S5: adding weighed Al-Ce-B master alloy to the melt obtained in step S4 and stirring for 5 minutes;

[0060] Step S6: testing the composition of the aluminum alloy melt obtained in step S5. After the composition is qualified, using argon as a carrier to blow a sodium-free refining agent into the aluminum alloy melt for refining and degassing. The degassing time is 10 minutes, and then slag is removed and left to stand for 10 minutes.

[0061] Step S7: The aluminum alloy melt obtained in step S6 is transferred to a side furnace of a die casting machine, the temperature of the side furnace is controlled at 685° C., and die casting is started after standing for 10 minutes. During the die casting process, the temperature of the mold is controlled at 200° C., the die casting speed is controlled at 6.0 m / s, and the vacuum degree is controlled at about 90 mbar;

[0062] Step S8: The die casting obtained in step S7 is naturally cooled, and then subjected to a short-time aging treatment, the aging treatment temperature is 250° C., and the aging treatment time is 2 h.

[0063] The die casting obtained in step S8 is fully filled. After sampling the die casting body, the yield strength of the body is measured to be 203 MPa, the thermal conductivity is 174 W / m·K, the size changes evenly during the interference fit process, and the maximum deformation after the interference fit is 0.26 mm.

[0064] Example 3

[0065] An aluminum alloy material is prepared according to the following steps. Based on the total weight of the aluminum alloy material, the aluminum alloy material comprises, by weight percentage: 9.3wt% Si, 0.78wt% Fe, 0.54wt% Mg, 0.036wt% Sr, 0.1wt% Ti, 0.8wt% C, 0.1wt% Sc, the remainder Al and inevitable impurity elements, wherein the inevitable impurity elements include 0.005wt% Cu, 0.01wt% Zn, 0.0006wt% B, 0.002wt% Mn, 0.003wt% Cr and 0.01wt% V.

[0066] Step S1: putting the aluminum ingot (99.9%) weighed according to the above alloy composition and the Al-50Si master alloy into a melting furnace, heating to 740° C. until they are completely melted;

[0067] Step S2: adding weighed Al-20Fe master alloy to the melt obtained in step S1, stirring and mixing, and keeping warm for 15 minutes;

[0068] Step S3: lowering the temperature of the melt obtained in step S2 to 720° C., adding weighed magnesium ingot (99.9%), and stirring and mixing;

[0069] Step S4: adding weighed Al-10Sr master alloy to the melt obtained in step S3, and stirring and mixing;

[0070] Step S5: adding weighed Al-Ti-C-Sc master alloy to the melt obtained in step S4 and stirring for 5 minutes;

[0071] Step S6: testing the composition of the aluminum alloy melt obtained in step S5. After the composition is qualified, using argon as a carrier to blow a sodium-free refining agent into the aluminum alloy melt for refining and degassing. The degassing time is 10 minutes, and then slag is removed and left to stand for 10 minutes.

[0072] Step S7: The aluminum alloy melt obtained in step S6 is transferred to a side furnace of a die-casting machine, the temperature of the side furnace is controlled at 675° C., and die-casting is started after standing for 10 minutes. During the die-casting process, the temperature of the mold is controlled at 160° C., the die-casting speed is controlled at 5.0 m / s, and the vacuum degree is controlled at about 80 mbar;

[0073] Step S8: The die casting obtained in step S7 is naturally cooled, and then subjected to a short-time aging treatment, wherein the aging treatment temperature is 250° C. and the aging treatment time is 0.5 h.

[0074] The die casting obtained in step S8 is fully filled. After sampling the die casting body, the yield strength of the body is measured to be 210 MPa, the thermal conductivity is 168 W / m·K, the size changes evenly during the interference fit process, and the maximum deformation after the interference fit is 0.1 mm.

[0075] Comparative Example 1

[0076] An aluminum alloy material is prepared according to the following steps. Based on the total weight of the aluminum alloy material, the aluminum alloy material comprises, by weight percentage: 9.3wt% Si, 0.77wt% Fe, 0.54wt% Mg, 0.035wt% Sr, 0.1wt% Ti, 0.18wt% B, the remainder Al and inevitable impurity elements, wherein the inevitable impurity elements include 0.005wt% Cu, 0.01wt% Zn, 0.002wt% Mn, 0.001wt% Cr and 0.007wt%.

[0077] Step S1: putting the aluminum ingot (99.9%) weighed according to the above alloy composition and the Al-50Si master alloy into a melting furnace, heating to 740° C. until they are completely melted;

[0078] Step S2: adding weighed Al-5Fe master alloy to the melt obtained in step S1, stirring and mixing, and keeping warm for 15 minutes;

[0079] Step S3: lowering the temperature of the melt obtained in step S2 to 720° C., adding weighed magnesium ingot (99.9%), and stirring and mixing;

[0080] Step S4: adding weighed Al-10Sr master alloy to the melt obtained in step S3, and stirring and mixing;

[0081] Step S5: adding weighed Al-Ti-B master alloy to the melt obtained in step S4 and stirring for 5 minutes;

[0082] Step S6: testing the composition of the aluminum alloy melt obtained in step S5. After the composition is qualified, using argon as a carrier to blow a sodium-free refining agent into the aluminum alloy melt for refining and degassing. The degassing time is 10 minutes, and then slag is removed and left to stand for 10 minutes.

[0083] Step S7: The aluminum alloy melt obtained in step S6 is transferred to a side furnace of a die-casting machine, the temperature of the side furnace is controlled at 675° C., and die-casting is started after standing for 10 minutes. During the die-casting process, the temperature of the mold is controlled at 160° C., the die-casting speed is controlled at 5.0 m / s, and the vacuum degree is controlled at about 80 mbar;

[0084] Step S8: The die casting obtained in step S7 is naturally cooled, and then subjected to a short-time aging treatment, wherein the aging treatment temperature is 250° C. and the aging treatment time is 0.5 h.

[0085] The die casting obtained in step S8 is fully filled. After sampling the die casting body, the yield strength of the body is measured to be 185MPa, the thermal conductivity is 123W / m·K, the size changes unevenly during the interference fit process and the maximum deformation after the interference fit is 1.2mm.

[0086] Comparative Example 2

[0087] An aluminum alloy material is prepared according to the following steps. The aluminum alloy material comprises, based on the total weight of the aluminum alloy material, 8.5wt% Si, 0.8wt% Fe, 0.2wt% Mg, 0.025wt% Sr, 0.02wt% B, 0.01wt% La, the remainder Al and inevitable impurity elements, wherein the inevitable impurity elements include 0.005wt% Cu, 0.01wt% Zn, 0.002wt% Mn, 0.001wt% Cr and 0.007wt%.

[0088] Step S1: putting the aluminum ingot (99.9%) weighed according to the above alloy composition and the Al-50Si master alloy into a melting furnace, heating to 740° C. until they are completely melted;

[0089] Step S2: adding weighed Al-10Fe master alloy to the melt obtained in step S1, and stirring and mixing;

[0090] Step S3: lowering the temperature of the melt obtained in step S2 to 730° C., adding weighed magnesium ingot (99.9%), and stirring and mixing;

[0091] Step S4: adding weighed Al-10Sr master alloy to the melt obtained in step S3, stirring and mixing, and keeping warm for 10 minutes;

[0092] Step S5: adding weighed Al-La-B master alloy to the melt obtained in step S4 and stirring for 5 minutes;

[0093] Step S6: testing the composition of the aluminum alloy melt obtained in step S5. After the composition is qualified, nitrogen is used as a carrier to blow a sodium-free refining agent into the aluminum alloy melt for refining and degassing. The degassing time is 15 minutes, and then the slag is removed and left to stand for 15 minutes.

[0094] Step S7: The aluminum alloy melt obtained in step S6 is transferred to a side furnace of a die-casting machine, the temperature of the side furnace is controlled at 670° C., and die-casting is started after standing for 10 minutes. During the die-casting process, the temperature of the mold is controlled at 150° C., the die-casting speed is controlled at 4.5 m / s, and the vacuum degree is controlled at about 80 mbar;

[0095] Step S8: The die casting obtained in step S7 is naturally cooled, and then subjected to a short-time aging treatment, wherein the aging treatment temperature is 300° C. and the aging treatment time is 0.5 h.

[0096] The die casting obtained in step S8 is fully filled. After sampling the die casting body, the yield strength of the body is measured to be 120 MPa, the thermal conductivity is 165 W / m·K, the size changes unevenly during the interference fit process, and the maximum deformation after the interference fit is 1.5 mm.

[0097] Comparative Example 3

[0098] An aluminum alloy material is prepared according to the following steps. Based on the total weight of the aluminum alloy material, the aluminum alloy material comprises, by weight percentage: 8.5wt% Si, 0.8wt% Fe, 0.46wt% Mg, 0.025wt% Sr, 0.02wt% B, 0.2wt% La, the remainder Al and inevitable impurity elements, wherein the inevitable impurity elements include 0.005wt% Cu, 0.01wt% Zn, 0.002wt% Mn, 0.001wt% Cr and 0.007wt%.

[0099] Step S1: putting an aluminum ingot (99.7%) weighed according to the above alloy composition and quick-dissolving silicon into a smelting furnace, heating to 750° C. until they are completely melted;

[0100] Step S2: adding weighed Al-10Fe master alloy to the melt obtained in step S1, and stirring and mixing;

[0101] Step S3: lowering the temperature of the melt obtained in step S2 to 730° C., adding weighed magnesium ingot (99.9%), and stirring and mixing;

[0102] Step S4: adding weighed Al-10Sr master alloy to the melt obtained in step S3, stirring and mixing, and keeping warm for 10 minutes;

[0103] Step S5: adding weighed Al-La master alloy and Al-B master alloy to the melt obtained in step S4, and stirring for 5 minutes;

[0104] Step S6: testing the composition of the aluminum alloy melt obtained in step S5. After the composition is qualified, nitrogen is used as a carrier to blow a sodium-free refining agent into the aluminum alloy melt for refining and degassing. The degassing time is 15 minutes, and then the slag is removed and left to stand for 15 minutes.

[0105] Step S7: The aluminum alloy melt obtained in step S6 is transferred to a side furnace of a die-casting machine, the temperature of the side furnace is controlled at 670° C., and die-casting is started after standing for 10 minutes. During the die-casting process, the temperature of the mold is controlled at 150° C., the die-casting speed is controlled at 4.5 m / s, and the vacuum degree is controlled at about 80 mbar;

[0106] Step S8: The die casting obtained in step S7 is naturally cooled, and then subjected to a short-time aging treatment, wherein the aging treatment temperature is 300° C. and the aging treatment time is 0.5 h.

[0107] The die casting obtained in step S8 is fully filled. After sampling the die casting body, the yield strength of the body is measured to be 175MPa, the thermal conductivity is 156W / m·K, the size changes unevenly during the interference fit process and the maximum deformation after the interference fit is 0.8mm.

[0108] Comparative Example 4

[0109] An aluminum alloy material is prepared according to the following steps. The aluminum alloy material comprises, based on the total weight of the aluminum alloy material, 9.0wt% Si, 0.83wt% Fe, 0.5wt% Mg, 0.04wt% Sr, 0.2wt% Ce, 0.02wt% B, the remainder Al and inevitable impurity elements, wherein the inevitable impurity elements include 0.005wt% Cu, 0.01wt% Zn, 0.002wt% Mn, 0.001wt% Cr, 0.007wt% V and 0.001wt% Ti.

[0110] Step S1: putting the aluminum ingot (99.7%) weighed according to the above alloy composition and the Al-20Si master alloy into a melting furnace, heating to 780° C. until they are completely melted;

[0111] Step S2: adding weighed Fe agent to the melt obtained in step S1, stirring and mixing, and keeping warm for 15 minutes;

[0112] Step S3: lowering the temperature of the melt obtained in step S2 to 740° C., adding weighed magnesium ingot (99.9%), and stirring and mixing;

[0113] Step S4: adding weighed Al-10Sr master alloy to the melt obtained in step S3, and stirring and mixing;

[0114] Step S5: adding weighed Al-Ce master alloy and Al-B master alloy to the melt obtained in step S4, and stirring for 5 minutes;

[0115] Step S6: testing the composition of the aluminum alloy melt obtained in step S5. After the composition is qualified, using argon as a carrier to blow a sodium-free refining agent into the aluminum alloy melt for refining and degassing. The degassing time is 10 minutes, and then slag is removed and left to stand for 10 minutes.

[0116] Step S7: The aluminum alloy melt obtained in step S6 is transferred to a side furnace of a die casting machine, the temperature of the side furnace is controlled at 685° C., and die casting is started after standing for 10 minutes. During the die casting process, the temperature of the mold is controlled at 200° C., the die casting speed is controlled at 6.0 m / s, and the vacuum degree is controlled at about 90 mbar;

[0117] Step S8: The die casting obtained in step S7 is naturally cooled, and then subjected to a short-time aging treatment, the aging treatment temperature is 250° C., and the aging treatment time is 2 h.

[0118] The die casting obtained in step S8 is fully filled. After sampling the die casting body, the yield strength of the body is measured to be 170MPa, the thermal conductivity is 150W / m·K, the size changes unevenly during the interference fit process and the maximum deformation after the interference fit is 1.0mm.

[0119] Comparative Example 5

[0120] An aluminum alloy material is prepared according to the following steps. Based on the total weight of the aluminum alloy material, the aluminum alloy material comprises, by weight percentage: 9.3wt% Si, 0.78wt% Fe, 0.54wt% Mg, 0.036wt% Sr, 0.1wt% Ti, 0.8wt% C, 0.2wt% Sc, the remainder Al and inevitable impurity elements, wherein the inevitable impurity elements include 0.005wt% Cu, 0.01wt% Zn, 0.0006wt% B, 0.002wt% Mn, 0.003wt% Cr and 0.01wt% V.

[0121] Step S1: putting the aluminum ingot (99.9%) weighed according to the above alloy composition and the Al-50Si master alloy into a melting furnace, heating to 740° C. until they are completely melted;

[0122] Step S2: adding weighed Al-20Fe master alloy to the melt obtained in step S1, stirring and mixing, and keeping warm for 15 minutes;

[0123] Step S3: lowering the temperature of the melt obtained in step S2 to 720° C., adding weighed magnesium ingot (99.9%), and stirring and mixing;

[0124] Step S4: adding weighed Al-10Sr master alloy to the melt obtained in step S3, and stirring and mixing;

[0125] Step S5: adding weighed Al-Ti-C master alloy and Al-Sc master alloy to the melt obtained in step S4, and stirring for 5 minutes;

[0126] Step S6: testing the composition of the aluminum alloy melt obtained in step S5. After the composition is qualified, using argon as a carrier to blow a sodium-free refining agent into the aluminum alloy melt for refining and degassing. The degassing time is 10 minutes, and then slag is removed and left to stand for 10 minutes.

[0127] Step S7: The aluminum alloy melt obtained in step S6 is transferred to a side furnace of a die-casting machine, the temperature of the side furnace is controlled at 675° C., and die-casting is started after standing for 10 minutes. During the die-casting process, the temperature of the mold is controlled at 160° C., the die-casting speed is controlled at 5.0 m / s, and the vacuum degree is controlled at about 80 mbar;

[0128] Step S8: The die casting obtained in step S7 is naturally cooled, and then subjected to a short-time aging treatment, wherein the aging treatment temperature is 250° C. and the aging treatment time is 0.5 h.

[0129] The die casting obtained in step S8 is fully filled. After sampling the die casting body, the yield strength of the body is measured to be 165MPa, the thermal conductivity is 148W / m·K, the size changes unevenly during the interference fit process and the maximum deformation after the interference fit is 1.2mm.

[0130] It can be seen from the above results that the above embodiments of the present invention achieve the following technical effects:

[0131] By comparing the results of Examples 1-3 with Comparative Example 1, it can be seen that, compared with Comparative Example 1 in which the composition and content of the elements are not completely within the scope of the present invention, the aluminum alloy materials in Examples 1-3 in which the composition and content of the elements are within the scope of the present invention have higher bulk yield strength, higher thermal conductivity and lower maximum deformation after interference fitting and are able to achieve uniform dimensional changes during the interference fitting process.

[0132] By comparing the results of Example 1 with those of Comparative Example 2, it can be seen that, compared with Comparative Example 2 in which the Mg content is outside the scope of the present invention, the aluminum alloy material in Example 1 in which the Mg content is within the scope of the present invention has a higher bulk yield strength, a higher thermal conductivity and a lower maximum deformation after interference fitting and is able to achieve uniform dimensional changes during the interference fitting process.

[0133] By comparing the results of Example 1 with those of Comparative Example 3, it can be seen that, compared with Comparative Example 3 in which the La content is outside the scope of the present invention, the aluminum alloy material in Example 1 in which the La content is within the scope of the present invention has a higher bulk yield strength, a higher thermal conductivity and a lower maximum deformation after interference fitting and is able to achieve uniform dimensional changes during the interference fitting process.

[0134] By comparing the results of Example 2 with those of Comparative Example 4, it can be seen that, compared with Comparative Example 4 in which the Ce content is outside the scope of the present invention, the aluminum alloy material in Example 2 in which the Ce content is within the scope of the present invention has higher bulk yield strength, higher thermal conductivity and lower maximum deformation after interference fitting and can achieve uniform dimensional changes during interference fitting.

[0135] By comparing the results of Example 3 with those of Comparative Example 5, it can be seen that, compared with Comparative Example 5 in which the Sc content is outside the scope of the present invention, the aluminum alloy material in Example 3 in which the Sc content is within the scope of the present invention has a higher bulk yield strength, a higher thermal conductivity and a lower maximum deformation after interference fitting and is able to achieve uniform dimensional changes during the interference fitting process.

[0136] It can be seen from the above results that compared with the aluminum alloy materials in Comparative Examples 1-5 in which the composition and content of elements are not completely within the scope of the present invention, the aluminum alloy materials in Examples 1-3 in which the composition and content of elements are within the scope of the present invention have higher bulk yield strength, higher thermal conductivity and lower maximum deformation after interference fitting and can achieve uniform dimensional changes during interference fitting.

[0137] The present invention introduces Al-La-B master alloy, Al-Ce-B master alloy or Al-Ti-C-Sc master alloy through comprehensive alloy component design, improves the poisoning behavior caused by simultaneous addition of Sr and B or simultaneous addition of Sc and Ti-B, and achieves the balance of forming performance, mechanical properties and thermal conductivity; at the same time, AlSiLa, AlSiCe or Al3(Sc) is precipitated in the alloy microstructure. 1-x Ti x) and other fine compound phases, combined with the adjustment of the die-casting temperature, mold temperature and die-casting speed in the die-casting process, it is possible to achieve uniform size changes during the interference fitting process and control the maximum deformation after the interference fitting. The aluminum alloy material of the present invention has excellent forming properties, mechanical properties and thermal conductivity, and can achieve uniform size changes during the interference fitting process and have a lower maximum deformation after the interference fitting. The method for preparing the aluminum alloy material of the present invention has a simple overall process and controllable production cost. It is suitable for large-scale batch production, and is particularly suitable for the production of aluminum alloy materials with a wall thickness of 1mm to 5mm. The bulk yield strength of the aluminum alloy material is ≥190MPa, the thermal conductivity is ≥165W / m·K, and the maximum deformation after the interference fitting can be controlled within the range of 0.1mm to 0.5mm.

[0138] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An aluminum alloy material, characterized in that: Based on the total weight of the aluminum alloy material, the aluminum alloy material comprises, by weight percentage: 8.5 to 9.3 wt% Si; 0.78 wt% to 0.83 wt% Fe; 0.46 wt% to 0.54 wt% Mg; 0.025 wt % to 0.04 wt % of Sr; and The balance of Al and unavoidable impurity elements, Wherein, the aluminum alloy material further comprises: 0.01wt% to 0.1wt% of B and 0.01wt% to 0.1wt% of La; or 0.01 wt% to 0.1 wt% of B and 0.01 wt% to 0.1 wt% of Ce; or 0.01 wt% to 0.1 wt% Ti, 0.1 wt% to 1 wt% C, and 0.01 wt% to 0.1 wt% Sc.

2. The aluminum alloy material according to claim 1, characterized in that: Among the inevitable impurity elements, Cu≤0.005wt%, Zn≤0.01wt%, Mn≤0.01wt%, Cr≤0.01wt%, and V≤0.01wt%.

3. A method for preparing the aluminum alloy material according to claim 1 or 2, characterized in that: The method comprises the following steps: Step S1: adding pure aluminum and pure silicon or aluminum-silicon master alloy into a smelting furnace, heating to 740° C. to 780° C., to obtain a first melt; Step S2: adding aluminum-iron master alloy or iron agent to the first melt, stirring and mixing, to obtain a second melt; Step S3: lowering the temperature of the second melt to 720° C. to 740° C., adding pure magnesium, and stirring and mixing to obtain a third melt; Step S4: adding aluminum strontium master alloy to the third melt, stirring and mixing, to obtain a fourth melt; Step S5: adding Al-La-B master alloy, Al-Ce-B master alloy or Al-Ti-C-Sc master alloy to the fourth melt, stirring and mixing, to obtain a first aluminum alloy melt; Step S6: testing the composition of the first aluminum alloy melt. After the composition is qualified, using nitrogen or an inert gas as a carrier to blow a refining agent into the first aluminum alloy melt for refining and degassing, then removing slag and standing to obtain a second aluminum alloy melt; Step S7: transferring the second aluminum alloy melt to a machine-side furnace of a die-casting machine, and performing die-casting after standing to obtain a die-casting part, wherein the temperature of the machine-side furnace is controlled at 670° C. to 685° C., the temperature of the mold during the die-casting process is controlled at 150° C. to 200° C., and the die-casting speed is controlled at 4.5 m / s to 6.0 m / s; and Step S8: Cooling the die casting and then performing aging treatment to obtain the aluminum alloy material.

4. The method according to claim 3, characterized in that In the Al-La-B master alloy, the content of La is 1 wt % to 10 wt %, and the content of B is 5 wt % to 20 wt %.

5. The method according to claim 3, characterized in that: In the Al-Ce-B master alloy, the content of Ce is 1wt% to 10wt%, and the content of B is 5wt% to 20wt%.

6. The method according to claim 3, characterized in that In the Al-Ti-C-Sc master alloy, the content of Ti is 1wt% to 10wt%, the content of C is 5wt% to 20wt%, and the content of Sc is 1wt% to 10wt%.

7. The method according to claim 3, characterized in that In the step S5, the addition amount of the Al-La-B master alloy, the Al-Ce-B master alloy or the Al-Ti-C-Sc master alloy accounts for 0.1wt% to 1wt% of the total weight of the aluminum alloy material.

8. The method according to any one of claims 3 to 7, characterized in that In the step S8, the temperature of the aging treatment is 250° C. to 300° C., and the time of the aging treatment is 0.5 h to 2 h.

9. The method according to any one of claims 3 to 7, characterized in that In the step S7, vacuum die casting is performed, and during the vacuum die casting process, the vacuum degree is controlled below 100 mbar.

10. The method according to any one of claims 3 to 7, characterized in that The bulk yield strength of the aluminum alloy material is ≥190 MPa, the thermal conductivity is ≥165 W / m·K, and the maximum deformation after interference fitting is controlled within the range of 0.1 mm to 0.5 mm.