High-strength high-thermal-conductivity aluminum alloy and preparation method thereof

Abstract

The application relates to a high-strength high-thermal-conductivity aluminum alloy and a preparation method thereof. The high-strength high-thermal-conductivity aluminum alloy comprises the following components: Si 9.0-11.0 wt%, Fe 0.5 wt%, Mg 0.5 wt%, Sc 0.4 wt%, Zn 0.005-0.01 wt%, Mn 0.01 wt%, B 0.02-0.04 wt%, Cu 0.02-0.05 wt%, inevitable impurities and the balance of aluminum. The high-strength high-thermal-conductivity aluminum alloy has the properties of high thermal conductivity and high strength, the tensile strength is greater than or equal to 270 MPa, the yield strength is greater than or equal to 173 MPa, the elongation is greater than or equal to 5.3%, the thermal conductivity is greater than or equal to 183 W / (m*K), the forming flowability is greater than or equal to 1330 mm, and the Brinell hardness is greater than or equal to 119 HB. The high-strength high-thermal-conductivity aluminum alloy can be recycled multiple times, and the high-strength high-thermal-conductivity aluminum alloy can still maintain high thermal conductivity, mechanical properties and flow forming properties after multiple recycling. The aluminum alloy has high-strength high-thermal-conductivity comprehensive performance, and the application of a proper amount of scandium elements is innovative on the basis of traditional high-strength aluminum alloys or high-thermal-conductivity aluminum alloys. The alloy is suitable for 3C electronic products with high requirements for heat dissipation and strength, such as mobile phones and notebooks.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of aluminum alloy materials, in particular to a high-strength and high-thermal-conductivity aluminum alloy and a preparation method thereof. BACKGROUND

[0002] Aluminum alloy is an important industrial raw material, which is widely used in aerospace, machinery, electronic and electrical products, mechanical manufacturing, chemical industry and other fields. In recent years, electronic and electrical products tend to be small in size, and the existing conventional aluminum alloy materials in the market have been difficult to meet the demand of high strength and high thermal conductivity of electronic and electrical products.

[0003] Chinese patent application CN103526082A discloses a high-thermal-conductivity cast aluminum alloy and a preparation method thereof. In the patent, the content of alloying element Si is reduced to 5.0-7.5%, supplemented by adding trace amounts of B, Ti and Zr and other elements, and the thermal conductivity of the alloy in the as-cast state reaches 160 W / (m·K). However, the mechanical properties of the aluminum alloy in the patent are low, and the tensile strength is only 135 MPa. Although the technology obtains an alloy with high thermal conductivity, the mechanical properties are poor, and it cannot meet the demand of high-strength performance of 3C electronic products.

[0004] Chinese patent CN10461971B discloses a high-thermal-conductivity aluminum alloy for die casting. The patent further reduces the content of Si to below 0.5wt%, and adds a certain amount of Fe (1.2-2.6wt.%), and the thermal conductivity of the alloy can reach 192 W / (m·K) at most, but the tensile strength and Brinell hardness of the alloy are only 142 MPa and 34.7 HB. The patent obtains an alloy with excellent thermal conductivity, but the mechanical properties are low; the pursuit of only thermal conductivity leads to low mechanical properties, which does not meet the requirement of high-strength performance of 3C electronic products.

[0005] Chinese patent CN108085541B discloses a thermal-conductivity aluminum alloy and its application. The thermal-conductivity aluminum alloy prepared in the patent has a tensile strength of not less than 250 MPa, a yield strength of not less than 150 MPa, an elongation of not less than 3.5%, and a thermal conductivity of not less than 150 W(m·K), but still faces the problem of insufficient strength of the thermal-conductivity aluminum alloy.

[0006] In addition, the existing high-strength or high-thermal-conductivity aluminum alloys have relatively poor comprehensive thermal conductivity and mechanical properties, and it is difficult to balance the performance of high thermal conductivity and high strength, and it is difficult to meet the performance requirements of 3C electronic products on heat dissipation and strength.

[0007] Therefore, it is urgent to develop a new aluminum alloy which has high thermal conductivity and high strength. SUMMARY

[0008] Based on this, the purpose of the present application is to provide a high-strength high-thermal-conductivity aluminum alloy, which has high strength, high thermal conductivity, high hardness, corrosion resistance, can be used repeatedly and still has high strength, thermal conductivity, hardness and corrosion resistance after repeated use, and is suitable for 3C electronic products with high heat dissipation and strength requirements.

[0009] A high-strength high-thermal-conductivity aluminum alloy comprises the following components: Si 9.0-11.0wt%, Fe 0.5wt%, Mg 0.5wt%, Sc 0.4wt%, Zn 0.005-0.01wt%, Mn 0.01wt%, B 0.02-0.04wt%, Cu 0.02-0.05wt%, inevitable impurities and the balance of aluminum.

[0010] The high-strength high-thermal-conductivity aluminum alloy disclosed by the application comprehensively considers the joint action of Si and other alloy elements. Firstly, Si 9.0-11.0wt% is adopted. The aluminum alloy in the content range is hypoeutectic alloy. In the aluminum alloy, with the increase of the Si content within 9.0-11.0wt%, the Si in the Al matrix gradually changes from fine particles to long needle-shaped distribution in the alpha-Al grain boundary, and then the lamellar eutectic structure gradually appears at the dendrite junction. With the increase of the eutectic structure, the Si phase is distributed in a network and separates the matrix, and the alpha-Al has obvious dendritic characteristics. The aluminum alloy in the content range has stable thermal conductivity. If the Si content is greater than 11.0wt%, the aluminum alloy is easily changed into a hypereutectic alloy, which will precipitate coarse primary silicon during solidification. When Si is dissolved in the Al matrix, it will become an electron scattering point, which will hinder the movement of electrons and reduce the thermal conductivity. The existence of elemental Si will also hinder the movement of electrons. If the Si content is less than 9.0wt%, the thermal conductivity of the aluminum alloy will rapidly decrease with the increase of the Si content. Therefore, the high-strength high-thermal-conductivity aluminum alloy of the application adopts Si 9.0-11.0wt% to make the thermal conductivity of the aluminum alloy stable. Secondly, on the basis of the Si content of 9.0-11.0wt%, the application adds 0.5wt% of Fe to form Al-Fe-Si phase with Si and Al, which can reduce the solid solubility of Si in Al and thus reduce the adverse effect of Si on the thermal conductivity of the aluminum alloy. Compared with the Al matrix, the conductivity of the Fe-rich phase is very low and can be regarded as an insulator. Fe in the alloy will form alpha-Fe (Chinese characters, which improves the strength and toughness) and beta-Fe (long needle-shaped, which destroys the toughness), but the Si content in alpha-Fe is lower and the Si content in beta-Fe is higher. If the Fe content is greater than 0.5wt%, with the increase of the Fe content, a large amount of beta-Fe phase will be formed, which will destroy the toughness of the aluminum alloy. In particular, after adding 0.5wt% of Fe in the aluminum alloy, the thermal conductivity of the aluminum alloy is improved. The reason why Fe can improve the thermal conductivity of the aluminum alloy is that Fe will form Al-Fe-Si ternary metal compound in the aluminum alloy, which can reduce the solid solubility of Si atoms in the aluminum matrix to a certain extent and improve the thermal conductivity of the aluminum alloy. On this basis, by adding 0.5wt% of Sc in the aluminum alloy, on the basis of the improvement of the thermal conductivity of the aluminum alloy by 0.5wt% of Fe, the addition of 0.5wt% of Sc can further improve the thermal conductivity of the aluminum alloy, and also improve the strength, hardness and the like of the aluminum alloy. Sc has a dispersion strengthening effect on aluminum, can promote the grain refinement of the aluminum alloy, improve the recrystallization temperature, can be used as an efficient grain refiner and effective recrystallization inhibitor in the aluminum alloy, and can greatly improve the strength, hardness and the like of the aluminum alloy. In addition, the addition of Sc in the aluminum alloy can also make the aluminum alloy have good superplasticity. The addition of 0.4wt% of Sc in the aluminum alloy can make the elongation rate of the aluminum alloy reach 12% together with other components.In addition, the application can greatly improve the mechanical properties of the aluminum alloy without significantly reducing the thermal conductivity of the aluminum alloy by adding an appropriate amount of Mg element (0.5wt%) in the aluminum alloy with high Si content (9.0-11.0wt%). In addition, there is a large solid solubility difference of alloying elements at high and low temperatures, so the strength of the aluminum alloy is improved by solid solution strengthening and aging strengthening; the application adds 0.005-0.01wt% Zn in the aluminum alloy containing 0.5wt% Mg element, the Zn element and the Mg element generate Mg2Zn strengthening phase, which significantly improves the strength of the aluminum alloy, and at the same time, the Si solid solubility in the aluminum alloy base body is reduced to improve the heat conduction, and the morphology and distribution of Si in the aluminum alloy are affected. In addition, the addition of Zn element in the Al-Si alloy can promote the precipitation of primary Si phase and reduce the solid solubility of Si atoms in the alpha-Al phase. The application adds 0.01wt% Mn, which significantly refines the grains, increases the resistance by easily solidifying in the Al matrix, and reduces the harmful effects of Fe-rich phases in the aluminum alloy. The application adds 0.02-0.04wt% B as a quality modifier to modify the aluminum alloy, reduce the secondary dendrite arm spacing of primary alpha-Al, make alpha-Al round and small, refine eutectic silicon from coarse needle-like to fine fibrous, improve the thermal conductivity and mechanical properties, and at the same time, the size of Fe-rich phase can be reduced. The application adds 0.02-0.05wt% Cu to improve the mechanical properties of the aluminum alloy, and if the Cu content is too high, it will seriously reduce the corrosion resistance of the aluminum alloy material and increase the tendency of thermal cracking.

[0011] The high-strength high-thermal-conductivity aluminum alloy has high-strength high-thermal-conductivity comprehensive performance, and innovatively adds an appropriate amount of scandium element on the basis of traditional high-strength aluminum alloy or high-thermal-conductivity aluminum alloy. The aluminum alloy of the application is suitable for 3C electronic products with high heat dissipation and strength requirements, such as mobile phones and laptops.

[0012] The high-strength high-thermal-conductivity aluminum alloy of the application has high thermal conductivity, high strength, high hardness, and corrosion resistance by the joint action of 9.0-11.0wt% Si, 0.5wt% Fe, 0.5wt% Mg, 0.4wt% Sc, 0.005-0.01wt% Zn, 0.01wt% Mn, 0.02-0.04wt% B, 0.02-0.05wt% Cu, and inevitable impurities and the balance of aluminum, so that the high-strength high-thermal-conductivity aluminum alloy has a tensile strength of ≥270MPa, a yield strength of ≥173MPa, an elongation of ≥5.3%, a thermal conductivity of ≥183W / (m·K), a forming flow of ≥1330mm, and a Brinell hardness of ≥119HB.

[0013] The high-strength high-thermal-conductivity aluminum alloy can be recycled multiple times, and the thermal conductivity, mechanical properties, flow forming property, and hardness of the aluminum alloy after multiple recycling can still meet the requirements. After 5 times of recycling, the tensile strength of the aluminum alloy is greater than or equal to 270 MPa, the yield strength is greater than or equal to 173 MPa, the elongation is greater than or equal to 5.3%, the thermal conductivity is greater than or equal to 176 MPa, the forming flow is greater than or equal to 1420 mm, and the Brinell hardness is greater than or equal to 117 HB. After 10 times of recycling, the tensile strength of the aluminum alloy is greater than or equal to 268 MPa, the yield strength is greater than or equal to 170 MPa, the elongation is greater than or equal to 5.2%, the thermal conductivity is greater than or equal to 163 MPa, the forming flow is greater than or equal to 1320 mm, and the Brinell hardness is greater than or equal to 116 HB. After 15 times of recycling, the tensile strength of the aluminum alloy is greater than or equal to 267 MPa, the yield strength is greater than or equal to 168 MPa, the elongation is greater than or equal to 5.1%, the thermal conductivity is greater than or equal to 152 MPa, the forming flow is greater than or equal to 1300 mm, and the Brinell hardness is greater than or equal to 114 HB.

[0014] Further, the Si content is 9.5-10.5wt%.

[0015] Further, the Zn content is 0.007-0.01wt%.

[0016] Further, the B content is 0.03wt%.

[0017] Further, the impurities are not more than 0.2wt%.

[0018] The application also provides a preparation method of the high-strength high-thermal-conductivity aluminum alloy.

[0019] The pure aluminum is put into a smelting furnace and is heated to 770-800℃ for melting by inert gas blowing;

[0020] Si is added at 730-760℃, and the mixture is melted and stirred uniformly, and is placed and kept warm for 10-20min;

[0021] Al-Fe, Al-Sc, Al-B, Al-Cu, and Al-Mn intermediate alloys are sequentially added at 730-750℃, and the mixture is melted and stirred uniformly, and is placed and kept warm for 10-20min;

[0022] Zn is added at 700-710℃ for melting and uniform stirring, and then Mg is added for melting and uniform stirring, and the mixture is placed and kept warm for 10-20min;

[0023] A refining agent is added for refining, the mixture is placed and kept warm for 10-20min, the dross is removed, the aluminum alloy melt is obtained, and the high-strength high-thermal-conductivity aluminum alloy is obtained by furnace casting.

[0024] The preparation method of the high-strength high-thermal-conductivity aluminum alloy is simple in operation and easy to control, adopts the intermediate alloy mode, has low melting temperature, can be smoothly melted at a temperature of 730-750 DEG C, saves energy and reduces consumption, and the obtained aluminum alloy has excellent comprehensive performance. DETAILED DESCRIPTION

[0025] The following detailed description of the high-strength high-thermal-conductivity aluminum alloy of the present application is provided, and it should be understood that the following examples are only used to illustrate and explain the present application, and are not used to limit the present application.

[0026] Example 1

[0027] The high-strength high-thermal-conductivity aluminum alloy of the present embodiment comprises the following components: Si 9.0wt%, Fe 0.5wt%, Mg 0.5wt%, Sc 0.4wt%, Zn 0.01wt%, Mn 0.01wt%, B 0.02wt%, Cu 0.05wt%, inevitable impurities and the balance of aluminum.

[0028] The raw materials of the present embodiment are pure aluminum, Si, Zn, Mg, Al-20Fe, Al-2Sc, Al-3B, Al-10Cu and Al-15Mn intermediate alloy, and the aluminum alloy components of the present embodiment are prepared and weighed.

[0029] The preparation method of the high-strength high-thermal-conductivity aluminum alloy of the present embodiment is as follows:

[0030] The pure aluminum is put into a smelting furnace and is blown with inert gas, and is heated to 770-800 DEG C for melting;

[0031] Si is added at 730-760 DEG C, and is melted and stirred uniformly, and is placed and kept for 10-20 min;

[0032] The Al-20Fe, Al-2Sc, Al-3B, Al-10Cu and Al-15Mn intermediate alloys are sequentially added at 730-750 DEG C, and are melted and stirred uniformly, and are placed and kept for 10-20 min;

[0033] Zn is added at 700-710 DEG C and is melted and stirred uniformly, and then Mg is added and is melted and stirred uniformly, and is placed and kept for 10-20 min;

[0034] A refining agent is added for refining, and is placed and kept for 10-20 min, and the dross is removed, and the aluminum alloy melt is obtained, and is poured and formed into the high-strength high-thermal-conductivity aluminum alloy of the present embodiment.

[0035] Example 2

[0036] The high-strength high-thermal-conductivity aluminum alloy of the embodiment comprises the following components: Si 11.0wt%, Fe 0.5wt%, Mg 0.5wt%, Sc 0.4wt%, Zn 0.005wt%, Mn 0.01wt%, B 0.04wt%, Cu 0.05wt%, inevitable impurities and the balance of aluminum.

[0037] The raw materials of the embodiment are pure aluminum, Si, Zn, Mg, Al-20Fe, Al-2Sc, Al-3B, Al-10Cu and Al-15Mn intermediate alloy, and the aluminum alloy components of the embodiment are prepared and weighed.

[0038] The preparation method of the high-strength high-thermal-conductivity aluminum alloy of the embodiment is the same as that of Embodiment 1.

[0039] Example 3

[0040] The high-strength high-thermal-conductivity aluminum alloy of the embodiment comprises the following components: Si 9.5wt%, Fe 0.5wt%, Mg 0.5wt%, Sc 0.4wt%, Zn 0.007wt%, Mn 0.01wt%, B 0.03wt%, Cu 0.02wt%, inevitable impurities and the balance of aluminum.

[0041] The raw materials of the embodiment are pure aluminum, Si, Zn, Mg, Al-20Fe, Al-2Sc, Al-3B, Al-10Cu and Al-15Mn intermediate alloy, and the aluminum alloy components of the embodiment are prepared and weighed.

[0042] The preparation method of the high-strength high-thermal-conductivity aluminum alloy of the embodiment is the same as that of Embodiment 1.

[0043] Example 4

[0044] The high-strength high-thermal-conductivity aluminum alloy of the embodiment comprises the following components: Si 10.5wt%, Fe 0.5wt%, Mg 0.5wt%, Sc 0.4wt%, Zn 0.01wt%, Mn 0.01wt%, B 0.03wt%, Cu 0.05wt%, inevitable impurities and the balance of aluminum.

[0045] The raw materials of the embodiment are pure aluminum, Si, Zn, Mg, Al-20Fe, Al-2Sc, Al-3B, Al-10Cu and Al-15Mn intermediate alloy, and the aluminum alloy components of the embodiment are prepared and weighed.

[0046] The preparation method of the high-strength high-thermal-conductivity aluminum alloy of the embodiment is the same as that of Embodiment 1.

[0047] Example 5

[0048] The high-strength high-thermal-conductivity aluminum alloy of the present embodiment includes the following components: Si 11.0 wt%, Fe 0.5 wt%, Mg 0.5 wt%, Sc 0.4 wt%, Zn 0.01 wt%, Mn 0.01 wt%, B 0.03 wt%, Cu 0.02 wt%, inevitable impurities, and the balance of aluminum.

[0049] The raw materials of the present embodiment include pure aluminum, Si, Zn, Mg, Al-20Fe, Al-2Sc, Al-3B, Al-10Cu, and Al-15Mn intermediate alloy, which are weighed and prepared according to the aluminum alloy components of the present embodiment.

[0050] The preparation method of the high-strength high-thermal-conductivity aluminum alloy of the present embodiment is the same as that of Example 1.

[0051] Comparative Example 1

[0052] The high-strength high-thermal-conductivity aluminum alloy of the present comparative example includes the following components: Si 7 wt%, Fe 1.0 wt%, Mg 1.0 wt%, Sc 0.4 wt%, Zn 0.02 wt%, Mn 0.02 wt%, B 0.08 wt%, Cu 0.03 wt%, inevitable impurities, and the balance of aluminum.

[0053] The raw materials of the present comparative example include pure aluminum, Si, Zn, Mg, Al-20Fe, Al-2Sc, Al-3B, Al-10Cu, and Al-15Mn intermediate alloy, which are weighed and prepared according to the aluminum alloy components of the present comparative example.

[0054] The preparation method of the high-strength high-thermal-conductivity aluminum alloy of the present comparative example is the same as that of Example 1.

[0055] Comparative Example 2

[0056] The high-strength high-thermal-conductivity aluminum alloy of the present comparative example includes the following components: Si 12 wt%, Fe 0.3 wt%, Mg 0.3 wt%, Zn 0.02 wt%, Mn 0.02 wt%, B 0.06 wt%, Cu 0.03 wt%, inevitable impurities, and the balance of aluminum.

[0057] The raw materials of the present comparative example include pure aluminum, Si, Zn, Mg, Al-20Fe, Al-2Sc, Al-3B, Al-10Cu, and Al-15Mn intermediate alloy, which are weighed and prepared according to the aluminum alloy components of the present comparative example.

[0058] The preparation method of the high-strength high-thermal-conductivity aluminum alloy of the present comparative example is the same as that of Example 1, except that Al-Sc intermediate alloy is not added.

[0059] Comparative Example 3

[0060] The high-strength high-thermal-conductivity aluminum alloy of the present comparative example comprises the following components: Si 4wt%, Fe 0.5wt%, Mg 0.5wt%, Sc 1.0wt%, Zn 0.02wt%, Mn 0.02wt%, B 0.06wt%, Cu 0.03wt%, inevitable impurities and the balance of aluminum.

[0061] The raw materials of the present comparative example are pure aluminum, Si, Zn, Mg, Al-20Fe, Al-2Sc, Al-3B, Al-10Cu and Al-15Mn intermediate alloy, which are prepared and weighed according to the aluminum alloy components of the present comparative example.

[0062] The preparation method of the high-strength high-thermal-conductivity aluminum alloy of the present comparative example is the same as that of Example 1.

[0063] The high-strength high-thermal-conductivity aluminum alloys obtained from Examples 1-5 and Comparative Examples 1-3 are tested for mechanical properties, thermal conductivity and flow forming properties.

[0064] Mechanical property determination: The tensile strength, yield strength and elongation of the aluminum alloy are tested according to GB / T 228.1-2010 Metal Materials Tensile Test Part 1: Room Temperature Test Method. The high-strength high-thermal-conductivity aluminum alloys obtained from Examples 1-5 and Comparative Examples 1-3 are extruded to form plates, which are cut into standard tensile specimens by wire cutting. The axial direction of the tensile specimen is consistent with the extrusion direction. The test results are shown in Table 1.

[0065] Thermal conductivity determination: The test is carried out according to ASTM E1461 Standard Method for Determining Thermal Diffusivity by Flash Method. The high-strength high-thermal-conductivity aluminum alloys obtained from Examples 1-5 and Comparative Examples 1-3 are prepared into circular specimens with a diameter of 12.7mm and a thickness of 25.4mm. Graphite coating is uniformly sprayed on both sides of the specimen to be tested. The treated specimen is placed in a laser thermal conductivity instrument for testing. The test results are shown in Table 1.

[0066] Flow forming property determination: The spiral line is used to determine the flowability of the aluminum alloy material. The high-strength high-thermal-conductivity aluminum alloys obtained from Examples 1-5 and Comparative Examples 1-3 are melted at 730℃, and then taken out of the furnace and air-cooled to 690℃ after complete melting. The flowability specimen is poured, and the length of the spiral line aluminum alloy specimen is measured. The results are shown in Table 1.

[0067] Brinell hardness determination: Brinell hardness tester is used for measurement.

[0068] Table 1-Performance test results of high-strength high-thermal-conductivity aluminum alloys of Examples 1-5 and Comparative Examples 1-3

[0069]

[0070]

[0071] As can be seen from the above table, the high-strength high-thermal-conductivity aluminum alloy of the present application not only has high thermal conductivity, strong mechanical properties and good flow forming properties, but also has a tensile strength ≥ 270 MPa, a yield strength ≥ 173 MPa, an elongation ≥ 5.3%, a thermal conductivity ≥ 183 MPa, a forming flow ≥ 1330 mm, and a Brinell hardness ≥ 119 HB. Compared with Comparative Examples 1-3 or the prior art, the high-strength high-thermal-conductivity aluminum alloy of the present application has good comprehensive performance. In Comparative Example 1, the content of some components deviates from the content range of the present application, the thermal conductivity of the obtained aluminum alloy is relatively poor, and the strength is also relatively low. In Comparative Example 2, Sc is not added and the content of some components deviates from the content range of the present application, the strength, thermal conductivity and tensile rate of the aluminum alloy of Comparative Example 2 are far lower than those of the aluminum alloy of the present application. In Comparative Example 3, the obtained aluminum alloy has relatively good comprehensive thermal conductivity and mechanical properties, but it is still difficult to balance, with a tensile strength of only 252 MPa and a yield strength of only 178 MPa, which cannot meet the performance requirements of 3C electronic products for heat dissipation and strength. The aluminum alloy obtained in the present application truly realizes the comprehensive performance balance of high thermal conductivity and high strength, and has obvious advantages compared with existing aluminum alloys.

[0072] In addition, the exfoliation corrosion of Examples 1-5 was tested according to GB / T 22639-2008, and the exfoliation corrosion rating of Examples 1-5 was higher than EA, and the corrosion resistance of the aluminum alloy of the present application was excellent.

[0073] Further, the mechanical properties and thermal conductivity of the high-strength high-thermal-conductivity aluminum alloy obtained from Examples 1-5 and Comparative Examples 1-3 after multiple recycling were tested.

[0074] Recycling of aluminum alloy: the high-strength high-thermal-conductivity aluminum alloy obtained from Examples 1-5 and Comparative Examples 1-3 was collected and melted at 760℃ for 1h, the molten material was placed in a crucible and mechanically stirred at a rate of 1200r / min for 30min, and the recycled thermal conductivity aluminum alloy was obtained after cooling. The tensile strength, yield strength, elongation, thermal conductivity and Brinell hardness of the aluminum alloy after 5, 10 and 15 times of recycling were determined according to the above-mentioned mechanical property, thermal conductivity and Brinell hardness determination methods, and the test results are shown in Table 2.

[0075] Table 2-Performance test results of high-strength high-thermal-conductivity aluminum alloy of Examples 1-5 and Comparative Examples 1-3 after multiple recycling

[0076]

[0077]

[0078] As can be seen from the comparison results of the comparative examples 1-5 and the comparative example 1-3, the high-strength high-thermal-conductivity aluminum alloy of the present application can be recycled for use for multiple times, and the thermal conductivity, mechanical properties, flow forming property and Brinell hardness can still meet the requirements after multiple recycling, the tensile strength of the aluminum alloy after 5 times of recycling is ≥270MPa, the yield strength is ≥173MPa, the elongation is ≥5.3%, the thermal conductivity is ≥176MPa, the forming flow property is ≥1420mm, and the Brinell hardness is ≥117HB; the tensile strength of the aluminum alloy after 10 times of recycling is ≥268MPa, the yield strength is ≥170MPa, the elongation is ≥5.2%, the thermal conductivity is ≥163MPa, the forming flow property is ≥1320mm, and the Brinell hardness is ≥116HB; the tensile strength of the aluminum alloy after 15 times of recycling is ≥267MPa, the yield strength is ≥168MPa, the elongation is ≥5.1%, the thermal conductivity is ≥152MPa, the forming flow property is ≥1300mm, and the Brinell hardness is ≥114HB.

[0079] Compared with the prior art, the high-strength high-thermal-conductivity aluminum alloy of the present application adds a proper amount of scandium element on the basis of the traditional high-strength aluminum alloy or high-thermal-conductivity aluminum alloy, and truly realizes the comprehensive performance of high thermal conductivity and high strength of the aluminum alloy, and has obvious advantages compared with the existing aluminum alloy. The aluminum alloy of the present application is suitable for 3C electronic products with high requirements for heat dissipation and strength, such as mobile phones and laptops.

[0080] The above-described embodiments only express several embodiments of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the patent. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, and the present application also intends to include these modifications and improvements.

Claims

1. A high-strength, high-thermal-conductivity aluminum alloy characterized by: The composition comprises: Si 9.0-11.0wt%, Fe 0.5wt%, Mg 0.5wt%, Sc 0.4wt%, Zn 0.007-0.01wt%, Mn 0.01wt%, B 0.03wt%, Cu 0.02-0.05wt%, inevitable impurities and the balance of aluminum; The preparation method of the high-strength high-thermal-conductivity aluminum alloy comprises the following steps: Purified aluminum is put into a smelting furnace and is heated to 770-800 DEG C for melting by inert gas blowing; Si is added at 730-760 DEG C, and is melted and stirred uniformly, and is kept for 10-20 min; Al-Fe, Al-Sc, Al-B, Al-Cu and Al-Mn intermediate alloys are added at 730-750 DEG C in sequence, and are melted and stirred uniformly, and are kept for 10-20 min; Zn is added at 700-710 DEG C for melting and stirring uniformly, and then Mg is added for melting and stirring uniformly, and is kept for 10-20 min; A refining agent is added for refining, and is kept for 10-20 min, and the dross is removed, so that the aluminum alloy melt is obtained, and the high-strength high-thermal-conductivity aluminum alloy is obtained by furnace casting.

2. The high strength, high thermal conductivity aluminum alloy of claim 1, wherein: The Si content is 9.5-10.5wt%.

3. The high strength, high thermal conductivity aluminum alloy of claim 1, wherein: The impurities are not more than 0.2wt%.

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