High-thermal-conductivity and high-plasticity aluminum alloy as well as preparation method and application thereof

Abstract

The invention provides a high-thermal-conductivity and high-plasticity aluminum alloy and a preparation method and application thereof. The aluminum alloy is composed of, by mass, 6-8% of Si, 0.5-1% of Fe, 0.001-0.1% of Mg, smaller than or equal to 0.05% of Mn, smaller than or equal to 0.05% of Cr, smaller than or equal to 0.05% of V, smaller than or equal to 0.1% of Ti, 0.01-0.1% of Sr, 0.001-0.1% of rare earth element RE and the balance Al and inevitable impurity elements, the single content of the impurity elements is smaller than or equal to 0.05%, and the total content of the impurity elements is smaller than or equal to 0.1%. The heat conductivity coefficient of the aluminum alloy is larger than or equal to 170 W / m.K, and the ductility is larger than or equal to 10%. The aluminum alloy provided by the invention has high heat conductivity and high plasticity, the safety and reliability of the aluminum alloy in the manufacturing and using processes are ensured while the heat dissipation requirement of a high-power chip is met, and large-scale popularization and application are facilitated.

Description

Technical Field

[0001] The present invention belongs to the technical field of alloy materials and relates to an aluminum alloy, in particular to an aluminum alloy with high thermal conductivity and high plasticity and a preparation method and application thereof. Background Art

[0002] In recent years, with the rapid development of autonomous driving technology, the computing power of chips used in autonomous driving has also been continuously improved. While these high-computing chips provide powerful computing power for autonomous driving systems, they also place higher requirements on the heat dissipation performance of their own hardware. This is because heat dissipation performance is not only directly related to the stability and life of the chip, but is also a key factor in ensuring the safe operation of the entire autonomous driving system.

[0003] In existing autonomous driving hardware, heat dissipation shells are mostly made of ADC12 or A380 aluminum alloy materials. However, the thermal conductivity of these materials is only 90-100W / m·K, and the elongation is as low as 1-3%, which can no longer meet the heat dissipation needs of autonomous driving hardware. Insufficient thermal conductivity will result in the inability to conduct heat quickly and effectively, while low plasticity means that the material is difficult to form complex shapes during the manufacturing process and is prone to rupture when impacted, which undoubtedly increases the safety risks of autonomous driving systems.

[0004] It can be seen that how to provide an aluminum alloy and a preparation method thereof that have both high thermal conductivity and high plasticity, while meeting the heat dissipation requirements of high-power chips and ensuring its safety and reliability during manufacturing and use has become an urgent problem that technical personnel in this field need to solve. Summary of the invention

[0005] The purpose of the present invention is to provide an aluminum alloy with high thermal conductivity and high plasticity, and a preparation method and application thereof. The aluminum alloy has both high thermal conductivity and high plasticity, and while meeting the heat dissipation requirements of high-power chips, ensures its safety and reliability during manufacturing and use, which is conducive to large-scale promotion and application.

[0006] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides an aluminum alloy with high thermal conductivity and high plasticity, wherein the aluminum alloy is composed of the following components in mass percentage: Si 6-8%, Fe 0.5-1%, Mg 0.001-0.1%, Mn≤0.05%, Cr≤0.05%, V≤0.05%, Ti≤0.1%, Sr 0.01-0.1%, rare earth element RE 0.001-0.1%, and the rest are Al and unavoidable impurity elements, and the individual content of the impurity elements is ≤0.05%, and the total content is ≤0.1%.

[0008] The thermal conductivity of the aluminum alloy is ≥170 W / m·K, and the elongation is ≥10%.

[0009] The present invention specially designs the chemical composition of aluminum alloy, takes advantage of the synergistic effect between different elements, and strictly limits the content of impurity elements, ultimately obtaining a cast aluminum alloy material with excellent comprehensive properties such as high thermal conductivity (thermal conductivity ≥ 170W / m·K), easy manufacturing (flowability ≥ 150mm) and high plasticity (elongation ≥ 10%), providing the autonomous driving industry with a new material option with better heat dissipation performance and higher safety performance.

[0010] Preferably, the element content in the aluminum alloy satisfies: (Mn+Cr+V+Ti)≤0.2%.

[0011] Preferably, the rare earth element RE is a mixed rare earth containing La, Ce and Nd.

[0012] In a second aspect, the present invention provides a method for preparing the aluminum alloy as described in the first aspect, the preparation method comprising the following steps:

[0013] (1) melting a pure aluminum ingot to obtain an aluminum melt;

[0014] (2) After heating the aluminum melt to a first temperature, adding silicon and / or Al-Si alloy and performing a first heat preservation treatment;

[0015] (3) After the silicon element is completely melted into the aluminum melt, the temperature is raised to a second temperature, an Al-rare earth alloy is added, and a second heat preservation treatment is performed;

[0016] (4) After the rare earth elements are completely melted into the aluminum melt, slag removal, slag stripping, smelting and refining are performed in sequence to obtain an intermediate melt;

[0017] (5) The intermediate melt is poured into a mold, and an Al-Ti-C grain refiner is added online to obtain an aluminum alloy after solidification and molding.

[0018] The present invention adds an Al-Ti-C grain refiner online during the preparation of the aluminum alloy, fully refines the α-Al grain size in the cast aluminum alloy material, and further improves the plasticity of the material.

[0019] Preferably, the purity of the pure aluminum ingot in step (1) is ≥99.5wt%.

[0020] Preferably, the melting process in step (1) is carried out in a melting furnace, and the melting temperature is ≥ 700°C.

[0021] Preferably, in step (2), the first temperature is 750-780°C.

[0022] Preferably, the time for the first insulation treatment in step (2) is 10-20 minutes.

[0023] Preferably, in step (3), the second temperature is 760-780°C.

[0024] Preferably, the time for the second heat preservation treatment in step (3) is 10-20 minutes.

[0025] Preferably, the slag removal in step (4) comprises: introducing nitrogen and / or argon into the aluminum melt, adding a slag removal agent, and controlling the slag removal temperature to be 730-750°C.

[0026] Preferably, the smelting in step (4) is accompanied by adding metal or alloy, and the smelting temperature is controlled at 720-750°C.

[0027] Preferably, composition detection is also performed between smelting and refining in step (4).

[0028] Preferably, the refining in step (4) comprises: introducing nitrogen and / or argon mixed with a refining agent into the aluminum melt for degassing and refining, while controlling the refining temperature to 720-730° C. and the refining time to 10-20 min.

[0029] Preferably, after the refining in step (4), the composition and slag content are also tested.

[0030] Preferably, the amount of the Al-Ti-C grain refiner added in step (5) accounts for 0.2-1% of the total mass of the intermediate melt.

[0031] As a preferred technical solution of the second aspect of the present invention, the preparation method comprises the following steps:

[0032] (1) melting a pure aluminum ingot with a purity of ≥99.5wt% in a melting furnace, while controlling the melting temperature to ≥700°C, to obtain an aluminum melt;

[0033] (2) After heating the aluminum melt to 750-780°C, add silicon and / or Al-Si alloy and keep the temperature for 10-20 minutes;

[0034] (3) After the silicon element is completely melted into the aluminum melt, the temperature is raised to 760-780°C, and the Al-rare earth alloy is added and kept warm for 10-20 minutes;

[0035] (4) After the rare earth elements are completely melted into the aluminum melt, nitrogen and / or argon are introduced, and a slag remover is added. Slag removal is performed at 730-750° C. After slag removal, the scum on the surface of the aluminum melt is scraped off, and metal or alloy is added and smelted at 720-750° C. After the component test is qualified, it is allowed to stand for 5-15 minutes, and then nitrogen and / or argon mixed with a refining agent are introduced for degassing and refining. At the same time, the refining temperature is controlled at 720-730° C. and the refining time is 10-20 minutes. Then, the component and slag content are tested. After the test is qualified, it is allowed to stand for 5-15 minutes to obtain an intermediate melt;

[0036] (5) pouring the intermediate melt into a mold, and adding an Al-Ti-C grain refiner online, while controlling the amount of the Al-Ti-C grain refiner added to account for 0.2-1% of the total mass of the intermediate melt, and obtaining an aluminum alloy after solidification and molding.

[0037] In a third aspect, the present invention provides a heat dissipation housing, wherein the heat dissipation housing is made of the aluminum alloy as described in the first aspect.

[0038] In a fourth aspect, the present invention provides a method for preparing the heat dissipation housing as described in the third aspect, the preparation method comprising remelting, casting, heat treatment and cooling performed in sequence.

[0039] The present invention not only eliminates defects such as vacancies and dislocations introduced during the shell casting process by heat treating the heat dissipation shell, but also promotes the dissolution of impurity atoms in a solid solution state in the aluminum matrix at high temperature to form compounds, ultimately further improving the thermal conductivity of the material.

[0040] Preferably, the heat treatment is carried out at a temperature of 200-400° C. and for a time of 2-10 h.

[0041] Preferably, the cooling rate is ≤50°C / h.

[0042] Preferably, the thermal conductivity of the heat dissipation housing is ≥190 W / m·K.

[0043] In a fifth aspect, the present invention provides a vehicle, comprising the heat dissipation housing as described in the third aspect.

[0044] The numerical range described in the present invention not only includes the point values ​​listed above, but also includes any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] (1) The present invention specially designs the chemical composition of aluminum alloy, takes advantage of the synergistic effect between different elements, and strictly limits the content of impurity elements, thereby ultimately obtaining a cast aluminum alloy material with excellent comprehensive properties such as high thermal conductivity (thermal conductivity coefficient ≥ 170 W / m·K), easy manufacturing (flowability ≥ 150 mm), and high plasticity (elongation ≥ 10%), providing the autonomous driving industry with a new material option with better heat dissipation performance and higher safety performance.

[0047] (2) The present invention adds Al-Ti-C grain refiner online during the preparation process of aluminum alloy, which fully refines the α-Al grain size in the cast aluminum alloy material, thereby further improving the plasticity of the material.

[0048] (3) The present invention not only eliminates defects such as vacancies and dislocations introduced during the shell casting process by heat treating the heat dissipation shell, but also promotes the dissolution of impurity atoms in the solid solution state in the aluminum matrix at high temperature to form compounds, ultimately further improving the thermal conductivity of the material. DETAILED DESCRIPTION

[0049] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0050] In order to meet the heat dissipation requirements of high-power chips while ensuring their safety and reliability during manufacturing and use, the present invention provides an aluminum alloy with high thermal conductivity and high plasticity, wherein the aluminum alloy is composed of the following components in mass percentage: Si6-8%, Fe 0.5-1%, Mg 0.001-0.1%, Mn≤0.05%, Cr≤0.05%, V≤0.05%, Ti≤0.1%, Sr 0.01-0.1%, rare earth element RE 0.001-0.1%, and the rest are Al and unavoidable impurity elements, and the individual content of the impurity elements is ≤0.05%, and the total content is ≤0.1%.

[0051] The present invention specially designs the chemical composition of aluminum alloy, takes advantage of the synergistic effect between different elements, and strictly limits the content of impurity elements, ultimately obtaining a cast aluminum alloy material with excellent comprehensive properties such as high thermal conductivity (thermal conductivity ≥ 170W / m·K), easy manufacturing (flowability ≥ 150mm) and high plasticity (elongation ≥ 10%), providing the autonomous driving industry with a new material option with better heat dissipation performance and higher safety performance.

[0052] In some embodiments, the mass percentage of Si is 6-8%, for example, it can be 6%, 6.2%, 6.4%, 6.6%, 6.8%, 7%, 7.2%, 7.4%, 7.6%, 7.8% or 8%, the mass percentage of Fe is 0.5-1%, for example, it can be 0.5%, 0.55%, 0.6%, 0.65%, 0.7%, 0.75%, 0.8%, 0.85%, 0.9%, 0.95% or 1%, and the mass percentage of Mg is 0.001-0.1%, for example, it can be 0.001%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.10%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15%, 0.16%, 0.17%, 0.18%, 0.19%, 0.20%, 0.21%, 0.22%, 0.23%, 0.24%, 0.25%, 0.26%, 0.27%, 0.28%, 0.29%, 0.30%, 0.31%, 0.32%, 0.33%, 0.34%, 0.35%, 0.36%, 0.37%, 0.38%, 0.39%, 0.40%, 0.41%, 0.42%, 0.43%, 0.44%, 0.45%, 0.46%, 0.47%, 0.48%, 0.49%, 0.50%, 0.51%, 0.5 08%, 0.09% or 0.1%, the mass percentage of Mn ≤0.05%, for example, it can be 0.01%, 0.015%, 0.02%, 0.025%, 0.03%, 0.035%, 0.04%, 0.045% or 0.05%, the mass percentage of Cr ≤0.05%, for example, it can be 0.01%, 0.015%, 0.02%, 0.025%, 0.03%, 0.035%, 0.04%, 0.045% or 0.05%, the mass percentage of V ≤0.05%, for example, it can be 0.01%, 0.015%, 0.02%, 0.025%, 0.03%, 0.035%, 0.04%, 0.045% or 0.05%. The mass percentage of Sr is 0.01-0.1%, for example, it can be 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09% or 0.1%, the mass percentage of rare earth element RE is 0.001-0.1%, for example, it can be 0.001%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09% or 0.1%. %, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09% or 0.1%, the single content of impurity elements is ≤0.05%, for example, it can be 0.01%, 0.015%, 0.02%, 0.025%, 0.03%, 0.035%, 0.04%, 0.045% or 0.05%, the total content of impurity elements is ≤0.1%, for example, it can be 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09% or 0.1%, but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0053] In the present invention, the addition of Si element is to improve the flowability of the material, so as to facilitate the casting of parts. When the Si element content is less than 6%, the material flowability is poor, which is not conducive to the casting of parts; when the Si element content is higher than 8%, the thermal conductivity of the material will be significantly reduced.

[0054] In the present invention, the addition of Fe element is beneficial to the demoulding of parts during the casting process. When the Fe element content is lower than 0.5%, the part casting process is prone to mold sticking, which is not conducive to part manufacturing; when the Fe element content is higher than 1%, the elongation of the material is significantly reduced.

[0055] In the present invention, the addition of Mg element is to form Mg with Si element. 2 Si strengthens the phase, thereby improving the strength of the material. When the Mg content is lower than 0.001%, the material strength is insufficient; when the Mg content is higher than 0.1%, the thermal conductivity of the material is significantly reduced.

[0056] In the present invention, the addition of Sr element is to refine the eutectic Si metal structure in the material. When the Sr element content is lower than 0.01%, the eutectic Si in the material cannot be fully refined, resulting in reduced plasticity of the material; when the Sr element content is higher than 0.1%, the thermal conductivity of the material will be significantly reduced.

[0057] In the present invention, the addition of rare earth element RE is to form intermetallic compounds with impurity elements in aluminum melt, eliminate the negative impact of impurity elements on the thermal conductivity of aluminum alloy materials, and further improve the thermal conductivity of materials. When the content of rare earth element RE is lower than 0.001%, the thermal conductivity of the material is significantly reduced; when the content of rare earth element RE is higher than 0.1%, the rare earth element itself is easy to form intermetallic compounds, resulting in a significant reduction in the plasticity of the material.

[0058] In some embodiments, the thermal conductivity of the aluminum alloy is ≥170 W / m·K, for example, it can be 170 W / m·K, 175 W / m·K, 180 W / m·K, 185 W / m·K, 190 W / m·K or 195 W / m·K, and the elongation is ≥10%, for example, it can be 10%, 12%, 14%, 16%, 18% or 20%, but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0059] In some embodiments, the element content in the aluminum alloy satisfies: (Mn+Cr+V+Ti)≤0.2%, for example, it can be 0.02%, 0.04%, 0.06%, 0.08%, 0.1%, 0.12%, 0.14%, 0.16%, 0.18% or 0.2%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0060] In the present invention, the presence of impurity elements such as Mn, Cr, V, and Ti will significantly reduce the thermal conductivity of the material, so it is necessary not only to strictly control the content of the individual elements, but also to strictly control the total amount of each element. When the total amount of the above four elements exceeds 0.2%, the thermal conductivity of the material will be significantly reduced.

[0061] In certain embodiments, the rare earth element RE is a mixed rare earth element containing La, Ce and Nd.

[0062] The present invention also provides a method for preparing the above aluminum alloy, the preparation method comprising the following steps:

[0063] (1) melting a pure aluminum ingot to obtain an aluminum melt;

[0064] (2) After heating the aluminum melt to a first temperature, adding silicon and / or Al-Si alloy and performing a first heat preservation treatment;

[0065] (3) After the silicon element is completely melted into the aluminum melt, the temperature is raised to a second temperature, an Al-rare earth alloy is added, and a second heat preservation treatment is performed;

[0066] (4) After the rare earth elements are completely melted into the aluminum melt, slag removal, slag stripping, smelting and refining are performed in sequence to obtain an intermediate melt;

[0067] (5) The intermediate melt is poured into a mold, and an Al-Ti-C grain refiner is added online to obtain an aluminum alloy after solidification and molding.

[0068] The present invention adds an Al-Ti-C grain refiner online during the preparation of the aluminum alloy, fully refines the α-Al grain size in the cast aluminum alloy material, and further improves the plasticity of the material.

[0069] In some embodiments, the purity of the pure aluminum ingot in step (1) is ≥99.5wt%, for example, it can be 99.5wt%, 99.55wt%, 99.6wt%, 99.65wt%, 99.7wt%, 99.75wt%, 99.8wt%, 99.85wt% or 99.9wt%, but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0070] In certain embodiments, the melting treatment in step (1) is carried out in a melting furnace, and the melting temperature is ≥ 700°C, for example, it can be 700°C, 705°C, 710°C, 715°C, 720°C, 725°C, 730°C, 735°C, 740°C, 745°C or 750°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0071] In some embodiments, the first temperature in step (2) is 750-780°C, for example, 750°C, 755°C, 760°C, 765°C, 770°C, 775°C or 780°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0072] In some embodiments, the time for the first insulation treatment in step (2) is 10-20 minutes, for example, it can be 10 minutes, 11 minutes, 12 minutes, 13 minutes, 14 minutes, 15 minutes, 16 minutes, 17 minutes, 18 minutes, 19 minutes or 20 minutes, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0073] In the present invention, when the first temperature is lower than 750°C or the time of the first insulation treatment is shorter than 10 minutes, silicon and / or Al-Si alloy is difficult to completely melt; when the first temperature is higher than 780°C or the time of the first insulation treatment is longer than 20 minutes, not only will the aluminum melt experience severe "hydrogen absorption" phenomenon, but also oxidation slag formation will occur, thereby adversely affecting the quality of the resulting aluminum alloy.

[0074] In some embodiments, the second temperature in step (3) is 760-780°C, for example, 760°C, 765°C, 770°C, 775°C or 780°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0075] In some embodiments, the time for the second insulation treatment in step (3) is 10-20 minutes, for example, it can be 10 minutes, 11 minutes, 12 minutes, 13 minutes, 14 minutes, 15 minutes, 16 minutes, 17 minutes, 18 minutes, 19 minutes or 20 minutes, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0076] In certain embodiments, the slag removal in step (4) includes: introducing nitrogen and / or argon into the aluminum melt, adding a slag removal agent, and controlling the slag removal temperature to 730-750°C, for example, it can be 730°C, 732°C, 734°C, 736°C, 738°C, 740°C, 742°C, 744°C, 746°C, 748°C or 750°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0077] In certain embodiments, the smelting in step (4) is accompanied by the addition of metal or alloy, and the smelting temperature is controlled to be 720-750°C, for example, 720°C, 725°C, 730°C, 735°C, 740°C, 745°C or 750°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0078] In certain embodiments, composition testing is performed between the smelting and refining in step (4).

[0079] In certain embodiments, the refining in step (4) includes: introducing nitrogen and / or argon mixed with a refining agent into the aluminum melt for degassing and refining, and controlling the refining temperature to 720-730°C, for example, 720°C, 721°C, 722°C, 723°C, 724°C, 725°C, 726°C, 727°C, 728°C, 729°C or 730°C, and the refining time to 10-20 min, for example, 10 min, 11 min, 12 min, 13 min, 14 min, 15 min, 16 min, 17 min, 18 min, 19 min or 20 min, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0080] In certain embodiments, the composition and slag content are also tested after the refining in step (4).

[0081] In some embodiments, the amount of the Al-Ti-C grain refiner added in step (5) is 0.2-1% of the total mass of the intermediate melt, for example, it can be 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9% or 1%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0082] In the present invention, the amount of the Al-Ti-C grain refiner added is crucial to taking into account both the grain refinement effect and the material plasticity. When the amount of the Al-Ti-C grain refiner added is less than 0.2%, the grain refinement effect cannot be achieved; when the amount of the Al-Ti-C grain refiner added is greater than 1%, the refiner itself is prone to form intermetallic compounds, thereby reducing the material plasticity.

[0083] The present invention also provides a heat dissipation housing, which is made of the above aluminum alloy.

[0084] The present invention also provides a method for preparing the heat dissipation housing, which comprises remelting, casting, heat treatment and cooling performed in sequence.

[0085] The present invention not only eliminates defects such as vacancies and dislocations introduced during the shell casting process by heat treating the heat dissipation shell, but also promotes the dissolution of impurity atoms in a solid solution state in the aluminum matrix at high temperature to form compounds, ultimately further improving the thermal conductivity of the material.

[0086] In some embodiments, the heat treatment temperature is 200-400°C, for example, it can be 200°C, 220°C, 240°C, 260°C, 280°C, 300°C, 320°C, 340°C, 360°C, 380°C or 400°C, and the time is 2-10h, for example, it can be 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h or 10h, but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0087] In the present invention, when the heat treatment temperature is lower than 200°C or the time is shorter than 2 hours, the purpose of the heat treatment cannot be fully achieved; when the heat treatment temperature is higher than 400°C or the time is longer than 10 hours, the thermal conductivity of the material will not be further improved, but will cause unnecessary waste of energy.

[0088] In some embodiments, the cooling rate is ≤50°C / h, for example, it can be 5°C / h, 10°C / h, 15°C / h, 20°C / h, 25°C / h, 30°C / h, 35°C / h, 40°C / h, 45°C / h or 50°C / h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0089] In the present invention, the cooling rate should not be too fast. When the cooling rate exceeds 50°C / h, it is impossible to promote the complete dissolution of impurity atoms, which is not conducive to further improving the thermal conductivity of the material.

[0090] In some embodiments, the thermal conductivity of the heat dissipation housing is ≥190 W / m·K, for example, it may be 190 W / m·K, 192 W / m·K, 194 W / m·K, 196 W / m·K, 198 W / m·K, 200 W / m·K, 202 W / m·K, 204 W / m·K, 206 W / m·K, 208 W / m·K or 210 W / m·K, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0091] Examples 1-9

[0092] This group of embodiments respectively provides an aluminum alloy with high thermal conductivity and high plasticity and a preparation method thereof. The chemical composition of the aluminum alloy provided in each embodiment is shown in Table 1 below.

[0093] Table 1

[0094]

[0095] In the above table, the rare earth element RE is a mixed rare earth containing La, Ce and Nd. Since the ratio of the three rare earth elements has no obvious effect on the performance of aluminum alloy, the specific content of each element is not determined in detail.

[0096] The aluminum alloys provided in this group of embodiments are prepared by the following methods, respectively, and the specific steps are as follows:

[0097] (1) melting a pure aluminum ingot with a purity of 99.8 wt% in a melting furnace while controlling the melting temperature to 720° C. to obtain an aluminum melt;

[0098] (2) After heating the aluminum melt to 760°C, add the Al-Si alloy and keep the temperature for 15 minutes;

[0099] (3) After the silicon element is completely melted into the aluminum melt, the temperature is raised to 770°C, and the Al-rare earth alloy is added and kept at this temperature for 15 minutes;

[0100] (4) After the rare earth elements are completely melted into the aluminum melt, nitrogen is introduced, and a slag remover (NaF) is added. Slag removal is performed at 740°C. After slag removal, the slag on the surface of the aluminum melt is removed. Mg and Sr raw materials are added and smelted at 740°C. After the composition test is qualified, the mixture is allowed to stand for 10 minutes, and then a mixture of a refining agent (AlCl 3 ) for degassing and refining with nitrogen, and at the same time controlling the refining temperature to 725°C for 15 minutes, and then testing the composition and slag content. After the test is qualified, it is allowed to stand for 10 minutes to obtain an intermediate melt;

[0101] (5) The intermediate melt is poured into a mold, and an Al-5Ti-0.8C grain refiner is added online. Meanwhile, the ratio of the amount of the Al-5Ti-0.8C grain refiner added to the total mass of the intermediate melt is controlled by referring to Table 1 above, and an aluminum alloy is obtained after solidification and molding.

[0102] Comparative Examples 1-6

[0103] This group of comparative examples respectively provides an aluminum alloy and a preparation method thereof. The chemical composition of the aluminum alloy provided by each comparative example is shown in Table 2 below.

[0104] Table 2

[0105]

[0106] In the above table, the rare earth element RE is a mixed rare earth containing La, Ce and Nd. Since the ratio of the three rare earth elements has no obvious effect on the performance of aluminum alloy, the specific content of each element is not determined in detail.

[0107] The aluminum alloy preparation method provided in this group of comparative examples is the same as that of Examples 1-9, except that the addition amounts of various metals and alloys are adjusted accordingly according to the chemical composition of the obtained aluminum alloy, so it will not be described in detail here.

[0108] Performance Testing

[0109] After testing, the performance parameters and determination results of the aluminum alloys obtained in Examples 1-9 and Comparative Examples 1-6 are shown in Table 3 below.

[0110] Table 3

[0111]

[0112]

[0113] In the above table, the fluidity of aluminum alloy is determined by spiral casting specimens and characterized by casting specimen length data; the casting temperature of aluminum liquid is 700°C and the mold temperature is 200°C. The qualified judgment standard requires that the aluminum alloy simultaneously meets the following requirements: elongation ≥10%, thermal conductivity ≥170W / (m·K), and fluidity ≥150mm.

[0114] It can be seen that the present invention specially designs the chemical composition of the aluminum alloy, takes advantage of the synergistic effect between different elements, and strictly limits the content of impurity elements, and finally obtains a cast aluminum alloy material with excellent comprehensive properties such as high thermal conductivity (thermal conductivity coefficient ≥ 170W / m·K), easy manufacturing (flowability ≥ 150mm) and high plasticity (elongation ≥ 10%), providing the autonomous driving industry with a new material option with better heat dissipation performance and higher safety performance.

[0115] In addition, the present invention adds an Al-Ti-C grain refiner online during the preparation of the aluminum alloy, which fully refines the α-Al grain size in the cast aluminum alloy material, thereby further improving the plasticity of the material.

[0116] Application Examples 1-3

[0117] This group of application examples uses the aluminum alloy obtained in Example 2 to prepare the heat dissipation shell. The specific preparation method includes remelting, casting, heat treatment and cooling in sequence, and the remelting temperature is 800°C, the casting time is 30 minutes, and the process parameters of heat treatment and cooling and the thermal conductivity of the obtained heat dissipation shell are shown in Table 4 below.

[0118] Table 4

[0119]

[0120] In the above table, the qualified judgment standard requires that the thermal conductivity of the heat dissipation shell is ≥190W / (m·K).

[0121] Comparative Application Examples 1-3

[0122] This group of comparative application examples respectively uses the aluminum alloy obtained in Example 2 to prepare the heat dissipation shell. The specific preparation method includes remelting, casting, heat treatment and cooling in sequence (only comparative application example 3 is not subjected to heat treatment and cooling), and the remelting temperature is 800°C, the casting time is 30 minutes, and the process parameters of heat treatment and cooling and the thermal conductivity of the obtained heat dissipation shell are shown in Table 5 below.

[0123] Table 5

[0124]

[0125] In the above table, the qualified judgment standard requires that the thermal conductivity of the heat dissipation shell is ≥190W / (m·K).

[0126] It can be seen that the present invention not only eliminates defects such as vacancies and dislocations introduced during the shell casting process by heat treating the heat dissipation shell, but also promotes the dissolution of impurity atoms in the solid solution state in the aluminum matrix at high temperature to form compounds, ultimately further improving the thermal conductivity of the material.

[0127] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A high thermal conductivity and high plasticity aluminum alloy, characterized in that: The aluminum alloy is composed of the following components in mass percentage: Si 6-8%, Fe 0.5-1%, Mg 0.001-0.1%, Mn≤0.05%, Cr≤0.05%, V≤0.05%, Ti≤0.1%, Sr 0.01-0.1%, rare earth element RE 0.001-0.1%, and the rest are Al and unavoidable impurity elements, and the individual content of the impurity elements is ≤0.05%, and the total content is ≤0.1%; The thermal conductivity of the aluminum alloy is ≥170W / m . K, elongation ≥ 10%.

2. The aluminum alloy according to claim 1, characterized in that The element content in the aluminum alloy satisfies: (Mn+Cr+V+Ti)≤0.2%.

3. The aluminum alloy according to claim 1 or 2, characterized in that: The rare earth element RE is a mixed rare earth containing La, Ce and Nd.

4. A method for preparing the aluminum alloy according to any one of claims 1 to 3, characterized in that: The preparation method comprises the following steps: (1) melting a pure aluminum ingot to obtain an aluminum melt; (2) After heating the aluminum melt to a first temperature, adding silicon and / or Al-Si alloy and performing a first heat preservation treatment; (3) After the silicon element is completely melted into the aluminum melt, the temperature is raised to a second temperature, an Al-rare earth alloy is added, and a second heat preservation treatment is performed; (4) After the rare earth elements are completely melted into the aluminum melt, slag removal, slag stripping, smelting and refining are performed in sequence to obtain an intermediate melt; (5) The intermediate melt is poured into a mold, and an Al-Ti-C grain refiner is added online to obtain an aluminum alloy after solidification and molding.

5. The preparation method according to claim 4, characterized in that: The purity of the pure aluminum ingot in step (1) is ≥ 99.5wt%; The melting process in step (1) is carried out in a melting furnace, and the melting temperature is ≥ 700°C; Step (2) the first temperature is 750-780° C.; Step (2) The first heat preservation treatment time is 10-20 minutes; Step (3) the second temperature is 760-780° C.; The time of the second heat preservation treatment in step (3) is 10-20 minutes.

6. The preparation method according to claim 4 or 5, characterized in that: The slag removal in step (4) comprises: introducing nitrogen and / or argon into the aluminum melt, adding a slag removal agent, and controlling the slag removal temperature to be 730-750° C.; The smelting in step (4) is accompanied by adding metal or alloy, and the smelting temperature is controlled to be 720-750° C.; In step (4), composition detection is also performed between smelting and refining; The refining in step (4) comprises: introducing nitrogen and / or argon mixed with a refining agent into the aluminum melt for degassing and refining, while controlling the refining temperature to be 720-730° C. and the refining time to be 10-20 min; After the refining in step (4), the composition and slag content are also tested; The amount of the Al-Ti-C grain refiner added in step (5) accounts for 0.2-1% of the total mass of the intermediate melt.

7. A heat dissipation housing, characterized in that: The heat dissipation housing is made of the aluminum alloy as described in any one of claims 1 to 3.

8. A method for preparing the heat dissipation housing according to claim 7, characterized in that: The preparation method comprises remelting, casting, heat treatment and cooling performed in sequence.

9. The preparation method according to claim 8, characterized in that: The heat treatment temperature is 200-400°C and the time is 2-10h; The cooling rate is ≤50°C / h; The thermal conductivity of the heat dissipation housing is ≥190W / m . K.

10. A vehicle, characterized in that: The vehicle comprises the heat dissipation housing according to claim 7.

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