CN-117926086-B - High-strength high-toughness Al-Mg-Si alloy

Abstract

The invention discloses a high-strength high-toughness Al-Mg-Si alloy, and belongs to the technical field of preparation of high-strength high-toughness aluminum alloys. According to the invention, through adding Cu, mn, sc and Zr elements, the alloy components are optimally designed, and the vacuum smelting, homogenizing treatment, asymmetric hot extrusion, solution treatment, pre-strain treatment and three-stage aging treatment processes are combined, so that the toughness of the aluminum alloy is obviously improved, compared with the conventional high-strength high-toughness aluminum alloy production, cu, sc, zr, mn elements are added to the components, and the aluminum alloy is greatly improved under the synergistic effects of fine grain strengthening, dislocation strengthening, deformation strengthening and second-phase strengthening by adopting the processes of asymmetric hot extrusion, solution treatment, pre-strain and three-stage aging treatment, so that the toughness is improved and the comprehensive performance of a finished product is ensured while the strength of the aluminum alloy is improved.

Inventors

• WEI HE
• LV QITAO
• LI ZULAI
• Chen Suokun
• ZHANG WENGAO
• Peng Mulan

Assignees

• 昆明理工大学

Dates

Publication Date

20260505

Application Date

20240125

Claims (4)

1. 1. The high-strength high-toughness Al-Mg-Si alloy is characterized in that the optimal performance of the strength and toughness of the Al-Mg-Si alloy is realized by adding Cu, mn, sc and Zr elements, optimizing the design of alloy components, and combining vacuum melting, homogenization treatment, asymmetric hot extrusion, solution treatment, pre-strain treatment and three-stage aging treatment processes; The high-strength high-toughness Al-Mg-Si alloy comprises, by mass, 0.6% -1.2% of Si, 0.7% -1.1% of Mg, 0.2% -0.8% of Mn, 0.5% -1.3% of Cu, 0.15% -0.5% of Sc, 0.15% -0.4% of Zr, the total content of unavoidable impurities is less than 0.2%, and the balance of Al; the preparation method of the high-strength high-toughness Al-Mg-Si alloy comprises the following steps: (1) Heating and melting pure Al, pure Mg, pure Cu, al-Si20 intermediate alloy, al-Mn10 intermediate alloy, al-Zr20 intermediate alloy and Al-Sc2 intermediate alloy, and pouring the alloy melt into a preheated die to form an aluminum alloy cast ingot after the alloy is completely melted to obtain alloy melt; (2) Homogenizing an aluminum alloy cast ingot to obtain a homogenized cast ingot; (3) Carrying out asymmetric hot extrusion on the homogeneous cast ingot, and then sequentially carrying out solid solution, prestrain and three-stage aging treatment to obtain a high-strength high-toughness Al-Mg-Si alloy; in the step (3), the temperature of asymmetric hot extrusion is 450-510 ℃, the extrusion deformation is 75-97%, the asymmetric ratio is (3:1) - (5:1), and the extrusion ratio is (20:1) - (25:1); in the step (3), the solid solution temperature is 525-545 ℃ and the solid solution time is 1-3 h; In the step (3), the deformation amount of the pre-strain is 0.5-5%; in the step (3), the three-stage aging treatment is specifically carried out at the first aging temperature of 140-160 ℃ for 4-8 hours, the second aging temperature of 160-185 ℃ for 6-10 hours and the third aging temperature of 140-160 ℃ for 4-8 hours.
2. 2. The high-strength and high-toughness Al-Mg-Si series alloy according to claim 1, wherein the temperature of the heat melting in the step (1) is 750 to 850 ℃.
3. 3. High strength and toughness Al according to claim 1 Mg The Si-based alloy is characterized in that in the step (1), the alloy melt is poured after standing and heat-preserving for 20min at 700-750 ℃.
4. 4. The high-strength and high-toughness Al-Mg-Si alloy according to claim 1, wherein in the step (2), the homogenization treatment is performed at a temperature of 450-520 ℃ and the heat preservation time is 3-6 hours.

Description

High-strength high-toughness Al-Mg-Si alloy Technical Field The invention belongs to the technical field of high-strength high-toughness aluminum alloy, and particularly relates to a high-strength high-toughness Al-Mg-Si alloy. Background With the development of national economy, the environmental protection performance and the recyclability of materials are increasingly emphasized. The Al-Mg-Si aluminum alloy has the advantages of low density, high specific strength, good formability, low stress corrosion sensitivity, high recycling rate and the like, and has been widely applied to the fields of construction, rail transit, aerospace and the like. However, with the continuous progress of technology, the existing Al-Mg-Si aluminum alloy cannot meet the requirements of manufacturers on the mechanical properties of the aluminum alloy. Currently, the addition of alloying elements to aluminum alloys, the adjustment of heat treatment processes, and the change of processing processes to improve the strength of Al-Mg-Si based aluminum alloys have reached the bottleneck. Therefore, a new mode means is needed to combine the four strengthening modes, and the toughness of the Al-Mg-Si aluminum alloy is improved from the strengthening mechanism of the aluminum alloy. The invention patent CN113621903B introduces a heat treatment method for improving the toughness of an aluminum alloy, which is mainly characterized in that the aluminum alloy is treated through the processes of homogenization treatment, solution treatment, stretching treatment, aging treatment and the like, so that the mechanical property of the aluminum alloy plate can be obviously improved, the tensile strength is improved by 5-10%, the yield strength is improved by 10-15%, and the elongation is improved by more than 50%. But the final toughness still does not meet the requirements of aluminum alloys in production. The invention patent CN111118418B discloses an aging treatment method for improving the toughness of Al-Zn-Mg-Cu aluminum alloy. The Al-Zn-Mg-Cu alloy is subjected to three-stage aging heat treatment. The aluminum alloy can obtain good strength and fracture toughness. However, the three-stage aging time is too long, the required time cost is high, the plasticity of the aluminum alloy is ignored, and the strengthening effect on the plasticity is not reflected. The invention patent CN115011846B discloses a high-strength and high-stability Al-Mg-Si-Cu-Sc aluminum alloy and a preparation method thereof, and an aluminum alloy material with the yield strength of more than or equal to 320MPa and the elongation of more than or equal to 10% is obtained through melting, casting, homogenizing treatment, extrusion, solution treatment, pre-strain treatment and time-efficient treatment. However, the strength of the aluminum alloy obtained by the method is low and is insufficient to meet the production requirements. Disclosure of Invention Aiming at the defects of the prior art, the invention provides a high-strength high-toughness Al-Mg-Si alloy. According to the invention, cu, mn, sc and Zr elements are added, and the purposes of improving the toughness performance of the aluminum-lithium alloy by adopting vacuum melting, homogenization treatment, asymmetric hot extrusion, solution treatment, pre-strain treatment and three-stage aging treatment are adopted. In order to achieve the above purpose, the technical scheme adopted by the invention is as follows: The high-strength high-toughness Al-Mg-Si alloy is optimally designed by adding Cu, mn, sc and Zr elements, and the optimal performance of the strength and toughness of the Al-Mg-Si alloy is realized by combining vacuum melting, homogenization treatment, asymmetric hot extrusion, solution treatment, pre-strain treatment and three-stage aging treatment processes. The high-strength high-toughness Al-Mg-Si alloy comprises, by mass, 0.6% -1.2% of Si, 0.7% -1.1% of Mg, 0.2% -0.8% of Mn, 0.5% -1.3% of Cu, 0.15% -0.5% of Sc, 0.15% -0.4% of Zr, the total content of unavoidable impurities is less than 0.2%, and the balance of Al. The preparation method of the high-strength high-toughness Al-Mg-Si alloy comprises the following steps: (1) Heating and melting pure Al, pure Mg, pure Cu, al-Si20 intermediate alloy, al-Mn10 intermediate alloy, al-Zr20 intermediate alloy and Al-Sc2 intermediate alloy, and pouring the alloy melt into a preheated die to form an aluminum alloy cast ingot after the alloy is completely melted to obtain alloy melt; (2) Homogenizing an aluminum alloy cast ingot to obtain a homogenized cast ingot; (3) And carrying out asymmetric hot extrusion on the homogeneous cast ingot, and then sequentially carrying out solid solution, prestrain and three-stage aging treatment to obtain the high-strength high-toughness Al-Mg-Si alloy. As a preferred embodiment of the present invention, in the step (1), the temperature of the heat melting is 750 to 850 ℃. In the step (1), the alloy melt is poured after being