Preparation method of high-strength and high-toughness aluminum-magnesium-silicon alloy

Abstract

The application discloses a preparation method of high-strength and high-toughness Al-Mg-Si alloy, and belongs to the technical field of aluminum alloy preparation.The process adopts the mode of melting + homogenization treatment + multi-pass asynchronous rolling + three-stage solid solution + pre-strain + aging treatment.The high-strength and high-toughness Al-Mg-Si alloy comprises the following components in percentage by mass: Si: 0.6% to 1.1%, Mg: 0.5% to 1.0%, Mn: 0.2% to 0.5%, Cu: 0.5% to 1.3%, Zr: 0.15% to 0.5%, Ce: 0.15% to 0.5%, and the sum of unavoidable impurity contents is less than 0.2%; and the balance is Al.The application optimizes the design of components and process, and through the mutual synergistic effect of solid solution strengthening, fine-grain strengthening, deformation strengthening and precipitation strengthening on the generated alloy phase, the Al-Mg-Si aluminum alloy with small grains and uniform structure is obtained, so that the strength and toughness of the Al-Mg-Si aluminum alloy are greatly improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of aluminum alloy preparation, and particularly relates to a preparation method of high-strength and high-toughness aluminum-magnesium-silicon alloy. BACKGROUND

[0002] As an alloy with the advantages of low density, high specific strength, good formability, low stress corrosion sensitivity, and high recycling rate, the Al-Mg-Si aluminum alloy has attracted much attention. In addition, the planning of green development of materials by the state makes the application prospect of the Al-Mg-Si aluminum alloy more broad. However, the mechanical properties (strength and toughness) of the aluminum alloy material cannot meet the demand of wide use of the aluminum alloy material, which seriously restricts the development of the aluminum alloy material. How to obtain the Al-Mg-Si aluminum alloy material with higher performance has attracted much attention of researchers. SUMMARY

[0003] In view of the above-mentioned defects of the prior art, the application provides a preparation method of high-strength and high-toughness aluminum-magnesium-silicon alloy.

[0004] To achieve the above-mentioned purpose, the technical scheme adopted by the application is as follows:

[0005] The preparation method of the high-strength and high-toughness aluminum-magnesium-silicon alloy is to optimize the design of the composition of the high-strength and high-toughness aluminum-magnesium-silicon alloy, and combine multi-pass asynchronous rolling, three-stage solid solution, pre-strain, and aging treatment to enhance the mechanical properties of the high-strength and high-toughness aluminum-magnesium-silicon alloy. The method comprises the following steps:

[0006] (1) proportioning raw materials of pure Al ingot, pure Mg ingot, Al-Cu60 intermediate alloy, Al-Si20 intermediate alloy, Al-Mn10 intermediate alloy, Al-Zr10 intermediate alloy, and Al-Ce5 intermediate alloy according to the proportion, and performing melting and pouring to obtain aluminum alloy cast ingot;

[0007] (2) performing homogenization treatment on the aluminum alloy cast ingot to obtain a homogenized cast ingot;

[0008] (3) performing multi-pass asynchronous rolling on the homogenized cast ingot, and then sequentially performing three-stage solid solution, pre-strain, and aging treatment to obtain the high-strength and high-toughness aluminum-magnesium-silicon alloy;

[0009] The high-strength and high-toughness aluminum-magnesium-silicon alloy comprises the following components with the mass percentage: Si: 0.6% to 1.1%, Mg: 0.5% to 1.0%, Mn: 0.2% to 0.5%, Cu: 0.5% to 1.3%, Zr: 0.15% to 0.5%, Ce: 0.15% to 0.5%, and the total content of unavoidable impurities is less than 0.2%; and the balance is Al.

[0010] As a preferred embodiment of the present application, the temperature of the multi-pass asynchronous rolling is 150-200 DEG C, the rolling speed is 0.5-1.2 m / s, the total deformation is 75-95%, the initial rolling reduction is 35-50%, the upper and lower roller speeds of the rolling are different, and the asynchronous speed ratio is 1:1.25-1:1.5.

[0011] As a preferred embodiment of the present application, the three-stage solid solution is as follows: the first-stage solid solution temperature is 500-525 DEG C, and the time is 0.5-2 h; the second-stage solid solution temperature is 540-565 DEG C, and the time is 0.5-2 h; and the third-stage solid solution temperature is 500-525 DEG C, and the time is 0.5-2 h.

[0012] As a preferred embodiment of the present application, the pre-strain is drawing, rolling or extrusion, and the strain rate is 1-5%.

[0013] As a preferred embodiment of the present application, the aging treatment temperature is 140-185 DEG C, and the time is 6-24 h.

[0014] As a preferred embodiment of the present application, the homogenization treatment temperature is 450 DEG C-550 DEG C, and the holding time is 3-5 h.

[0015] As a preferred embodiment of the present application, the melting temperature is 800 DEG C-850 DEG C, and the pouring temperature is 650 DEG C-750 DEG C.

[0016] The principle of the present application is as follows:

[0017] The present application can greatly improve the strength and toughness of the aluminum alloy by optimizing the composition of the high-strength high-toughness aluminum magnesium silicon alloy, combining multi-pass asynchronous rolling, three-stage solid solution, pre-strain and aging treatment. When the aluminum alloy is subjected to multi-pass asynchronous rolling, the grains are broken, a large number of dislocations are generated, and the microstructure of the aluminum alloy is further refined, and the uniformity of the structure is improved, due to the large deformation caused by rolling and the shear force specific to asynchronous rolling compared with ordinary rolling. After three-stage solid solution, the insoluble precipitates (Al2Cu, Al3Zr, Al3Ce, etc.) generated by the added Cu, Zr and Ce elements are dissolved into the aluminum matrix, and the solid solution strengthening effect is more obvious. Then, a large number of dislocations are generated in the aluminum alloy by pre-strain, a large number of channels are provided for atomic diffusion during the subsequent aging period, a large number of strengthening phases are precipitated, and the performance of the aluminum alloy is greatly enhanced. The strength and toughness of the aluminum alloy are greatly enhanced by the combined action of fine-grain strengthening, solid solution strengthening, deformation strengthening and precipitation strengthening.

[0018] In addition, the application cooperates with multi-pass asynchronous rolling + three-stage solid solution + pre-strain + aging treatment, so that the Cu-containing phase (QP1, QP2, Q) formed in the alloy improves the peak strength and toughness of the aluminum alloy, the primary Al3Zr particles can act as heterogeneous nucleation cores in the solidification process, and significantly refine the grains; the Ce element is adsorbed on the surface of the eutectic Si phase to form a large number of twins, and the Ce and Si, Cu, Mn and other elements in the alloy form an alloy phase, which hinders the growth of the alpha-Al phase in the solidification process, thereby playing a role in refining the grains and greatly enhancing the strength and toughness of the aluminum alloy.

[0019] Compared with the prior art, the application has the beneficial effects that: the application cooperates the composition of the Al-Mg-Si aluminum alloy with multi-pass asynchronous rolling + three-stage solid solution + pre-strain + aging treatment, and through the mutual cooperation of solid solution strengthening, fine-grain strengthening, deformation strengthening and precipitation strengthening of the generated alloy phase, an Al-Mg-Si aluminum alloy with small grains and uniform structure is obtained, so that the strength and toughness of the Al-Mg-Si aluminum alloy are greatly improved. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 The application discloses a preparation process of a high-strength and high-toughness aluminum magnesium silicon alloy. DETAILED DESCRIPTION

[0021] In order to better illustrate the purposes, technical solutions and advantages of the application, the application will be further described below in combination with specific examples.

[0022] Example 1

[0023] The chemical composition of the high-strength and high-toughness aluminum magnesium silicon alloy in the embodiment is shown in Table 1.

[0024] Table 1 Chemical composition (wt%) of the high-strength and high-toughness aluminum magnesium silicon alloy

[0025]

[0026] The preparation method of the high-strength and high-toughness aluminum magnesium silicon alloy comprises the following steps:

[0027] (1) According to the composition in Table 1, pure Al ingot, pure Mg ingot, Al-Cu60 intermediate alloy, Al-Si20 intermediate alloy, Al-Mn10 intermediate alloy, Al-Zr10 intermediate alloy and Al-Ce5 intermediate alloy are vacuum smelted and poured, the smelting temperature of vacuum smelting is 800 DEG C, and the pouring temperature is 750 DEG C, so as to form an aluminum alloy ingot with a size of 100*100*50.

[0028] (2) After completion, the aluminum alloy ingot is heated to 450°C for high-temperature solid solution for 5h, so that all elements are uniformly distributed, and after air cooling to 150°C, multi-pass asynchronous rolling is performed with an initial rolling reduction of 35% and a total deformation of 95% and a non-uniform speed ratio of 1:1.25; after cooling to room temperature, solid solution is performed at 500°C for 30min, and then heating to 560°C for solid solution for 2h, and finally solid solution at 500°C for 30min, and after water cooling, 1% drawing pre-strain is performed, and finally aging treatment is performed at a temperature of 160°C for 6h, and the tensile strength and elongation of the finally obtained aluminum alloy are shown in Table 2.

[0029] Table 2

[0030] Tensile strength / MPa Tensile strength / MPa Tensile strength / MPa 402 451 16.3％

[0031] Example 2

[0032] The chemical composition of the high-strength and high-toughness aluminum-magnesium-silicon alloy in the embodiment is shown in Table 3.

[0033] Table 3 Chemical composition of high-strength and high-toughness aluminum-magnesium-silicon alloy (wt%)

[0034]

[0035] The preparation method of the high-strength and high-toughness aluminum-magnesium-silicon alloy comprises the following steps:

[0036] (1) According to the components in Table 3, pure Al ingot, pure Mg ingot, Al-Cu60 intermediate alloy, Al-Si20 intermediate alloy, Al-Mn10 intermediate alloy, Al-Zr10 intermediate alloy and Al-Ce5 intermediate alloy are vacuum smelted and poured to form an aluminum alloy ingot with a size of 100*100*50.

[0037] (2) After completion, the aluminum alloy ingot is heated to 480°C for high-temperature solid solution for 5h, so that all elements are uniformly distributed, and after air cooling to 170°C, multi-pass asynchronous rolling is performed with an initial rolling reduction of 35% and a total deformation of 90% and a non-uniform speed ratio of 1:1.3; after cooling to room temperature, solid solution is performed at 505°C for 30min, and then heating to 555°C for solid solution for 2h, and finally solid solution at 505°C for 30min, and after water cooling, 2.5% rolling pre-strain is performed, and finally aging treatment is performed at a temperature of 170°C for 6h, and the tensile strength and elongation of the finally obtained aluminum alloy are shown in Table 4.

[0038] Table 4

[0039] Tensile strength / MPa Tensile strength / MPa Tensile strength / MPa 415 467 15.3％

[0040] Example 3

[0041] The chemical composition of the high-strength and high-ductility aluminum-magnesium-silicon alloy in the embodiment is shown in Table 5.

[0042] Table 5 Chemical composition of high-strength and high-ductility aluminum-magnesium-silicon alloy (wt%)

[0043]

[0044]

[0045] The preparation method of the high-strength and high-ductility aluminum-magnesium-silicon alloy includes the following steps:

[0046] (1) According to the components in Table 5, pure Al ingot, pure Mg ingot, Al-Cu60 intermediate alloy, Al-Si20 intermediate alloy, Al-Mn10 intermediate alloy, Al-Zr10 intermediate alloy, and Al-Ce5 intermediate alloy are vacuum melted and poured, the melting temperature of vacuum melting is 800℃, the pouring temperature is 750℃, and a 100*100*50 aluminum alloy ingot is formed.

[0047] (2) After completion, the aluminum alloy ingot is heated to 500℃ for 5h high-temperature solid solution, so that all elements are uniformly distributed, and after air cooling to 185℃, multi-pass asynchronous rolling is performed, the initial rolling reduction is 35%, the total deformation is 85%, and the asynchronous ratio is 1:1.4; after cooling to room temperature, solid solution is performed at 505℃ for 1h, then heated to 555℃ for 2h, and finally solid solution is performed at 505℃ for 30min, after water cooling, 3% extrusion pre-strain is performed, and finally aging treatment is performed at a temperature of 170℃ for 6h, and the tensile strength and elongation of the finally obtained aluminum alloy are shown in Table 6.

[0048] Table 6

[0049] Tensile strength / MPa Tensile strength / MPa Tensile strength / MPa 419 483 15.6％

[0050] Example 4

[0051] The chemical composition of the high-strength and high-ductility aluminum-magnesium-silicon alloy in the embodiment is shown in Table 7.

[0052] Table 7 Chemical composition of high-strength and high-ductility aluminum-magnesium-silicon alloy (wt%)

[0053]

[0054] The preparation method of the high-strength and high-ductility aluminum-magnesium-silicon alloy includes the following steps:

[0055] (1) According to the components in Table 7, first, pure Al ingot, pure Mg ingot, Al-Cu60 intermediate alloy, Al-Si20 intermediate alloy, Al-Mn10 intermediate alloy, Al-Zr10 intermediate alloy and Al-Ce5 intermediate alloy are vacuum smelted and poured, the smelting temperature of vacuum smelting is 800℃, the pouring temperature is 750℃, and a 100*100*50 aluminum alloy ingot is formed.

[0056] (2) After completion, the aluminum alloy ingot is heated to 510℃ for 5h high temperature solid solution, so that all elements are uniformly distributed, and is subjected to multi-pass asynchronous rolling when air-cooled to 200℃, the initial rolling reduction is 35%, the total deformation is 80%, and the asynchronous ratio is 1:1.5; after cooling to room temperature, it is solid-solved at 500℃ for 1h, then heated to 545℃ for 2h, and finally solid-solved at 500℃ for 30min, and after water cooling, 5% drawing pre-strain is carried out, and finally aging treatment is carried out at a temperature of 170℃ for 24h, and the tensile strength and elongation of the finally obtained aluminum alloy are shown in Table 8.

[0057] Table 8

[0058] Tensile strength / MPa Tensile strength / MPa Tensile strength / MPa 423 486 14.7％

[0059] Example 5

[0060] The chemical composition of the high-strength high-toughness aluminum magnesium silicon alloy in the embodiment is shown in Table 9.

[0061] Table 9 Chemical composition of high-strength high-toughness aluminum magnesium silicon alloy (wt%)

[0062]

[0063] The preparation method of the high-strength high-toughness aluminum magnesium silicon alloy comprises the following steps:

[0064] (1) According to the components in Table 9, first, pure Al ingot, pure Mg ingot, Al-Cu60 intermediate alloy, Al-Si20 intermediate alloy, Al-Mn10 intermediate alloy, Al-Zr10 intermediate alloy and Al-Ce5 intermediate alloy are vacuum smelted and poured, the smelting temperature of vacuum smelting is 850℃, the pouring temperature is 650℃, and a 100*100*50 aluminum alloy ingot is formed.

[0065] (2) After completion, the aluminum alloy ingot is heated to 550°C for high-temperature solid solution for 3h, so that all elements are uniformly distributed, and after air cooling to 150°C, multi-pass asynchronous rolling is performed with an initial rolling reduction of 50% and a total deformation of 75% and a asynchronous ratio of 1:1.5; after cooling to room temperature, solid solution is performed at 525°C for 2h, and then solid solution is performed at 565°C for 0.5h, and finally solid solution is performed at 525°C for 2h, and after water cooling, 5% drawing pre-strain is performed, and finally aging treatment is performed at a temperature of 140°C for 12h, and the tensile strength and elongation of the finally obtained aluminum alloy are shown in Table 10.

[0066] Table 10

[0067] Tensile strength / MPa Tensile strength / MPa Tensile strength / MPa 406 459 14.5％

[0068] Comparative Example 1

[0069] The high-strength high-toughness aluminum magnesium silicon alloy of the present comparative example has the chemical composition shown in Table 11.

[0070] Table 11 Chemical composition of high-strength high-toughness aluminum magnesium silicon alloy (wt%)

[0071]

[0072] The preparation method of the high-strength high-toughness aluminum magnesium silicon alloy comprises the following steps:

[0073] (1) According to the components in Table 11, pure Al ingot, pure Mg ingot, Al-Cu60 intermediate alloy, Al-Si20 intermediate alloy, Al-Mn10 intermediate alloy, Al-Zr10 intermediate alloy and Al-Ce5 intermediate alloy are vacuum smelted and poured to form an aluminum alloy ingot with a size of 100*100*50.

[0074] (2) After completion, the aluminum alloy ingot is heated to 500°C for high-temperature solid solution for 5h, so that all elements are uniformly distributed, and after air cooling to 150°C, multi-pass rolling is performed with an initial rolling reduction of 35% and a total deformation of 90%; after cooling to room temperature, solid solution is performed at 545°C for 2h, and finally aging treatment is performed at a temperature of 170°C for 6h, and the tensile strength and elongation of the finally obtained aluminum alloy are shown in Table 12.

[0075] Table 12

[0076] Tensile strength / MPa Tensile strength / MPa Tensile strength / MPa 352 396 12.5％

[0077] Comparative Example 2:

[0078] The high-strength high-toughness aluminum magnesium silicon alloy of the present comparative example has the chemical composition shown in Table 13.

[0079] Table 13 Chemical composition of high-strength and high-ductility aluminum-magnesium-silicon alloy (wt%)

[0080]

[0081] A method for preparing a high-strength and high-ductility aluminum-magnesium-silicon alloy includes the following steps:

[0082] (1) Pure Al ingot, pure Mg ingot, Al-Cu60 intermediate alloy, Al-Si20 intermediate alloy, Al-Mn10 intermediate alloy, Al-Zr10 intermediate alloy, and Al-Ce5 intermediate alloy are first vacuum melted and cast according to the components in Table 13, the melting temperature of vacuum melting is 850°C, the casting temperature is 750°C, and an aluminum alloy ingot with a size of 100*100*50 is formed.

[0083] (2) After completion, the aluminum alloy ingot is heated to 480°C for 5h of high-temperature solid solution, so that all elements are uniformly distributed, and after air cooling to 180°C, multi-pass rolling is performed, the initial rolling reduction is 35%, and the total deformation is 95%; after cooling to room temperature, solid solution is performed at a temperature of 525°C for 2h, and finally aging treatment is performed at a temperature of 170°C for 12h, and the tensile strength and elongation of the finally obtained aluminum alloy are shown in Table 14.

[0084] Table 14

[0085] Tensile strength / MPa Tensile strength / MPa Tensile strength / MPa 343 387 12.3％

[0086] Comparative Example 3

[0087] The chemical composition of the high-strength and high-ductility aluminum-magnesium-silicon alloy of the present comparative example is shown in Table 15.

[0088] Table 15 Chemical composition of high-strength and high-ductility aluminum-magnesium-silicon alloy (wt%)

[0089]

[0090] A method for preparing a high-strength and high-ductility aluminum-magnesium-silicon alloy includes the following steps:

[0091] (1) Pure Al ingot, pure Mg ingot, Al-Cu60 intermediate alloy, Al-Si20 intermediate alloy, Al-Mn10 intermediate alloy, Al-Zr10 intermediate alloy, and Al-Ce5 intermediate alloy are first vacuum melted and cast according to the components in Table 15, the melting temperature of vacuum melting is 800°C, the casting temperature is 750°C, and an aluminum alloy ingot with a size of 100*100*50 is formed.

[0092] (2) After completion, the aluminum alloy ingot is heated to 450°C for high-temperature solid solution for 5h to make all elements uniformly distributed, and then air-cooled to 150°C for multi-pass asynchronous rolling with an initial rolling reduction of 35% and a total deformation of 95% and a non-uniform speed ratio of 1:1.25; after cooling to room temperature, solid solution at 500°C for 30min, then heated to 560°C for solid solution for 2h, and finally solid solution at 500°C for 30min, and finally aging treatment at a temperature of 160°C for 6h, and the tensile strength and elongation of the finally obtained aluminum alloy are shown in Table 18.

[0093] Table 16

[0094] Tensile strength / MPa Tensile strength / MPa Tensile strength / MPa 346 387 13.6％

[0095] Comparative Example 4

[0096] The high-strength and high-toughness aluminum-magnesium-silicon alloy of the present comparative example has the chemical composition shown in Table 17.

[0097] Table 17 Chemical composition of high-strength and high-toughness aluminum-magnesium-silicon alloy (wt%)

[0098]

[0099] The preparation method of the high-strength and high-toughness aluminum-magnesium-silicon alloy comprises the following steps:

[0100] (1) The pure Al ingot, pure Mg ingot, Al-Cu60 intermediate alloy, Al-Si20 intermediate alloy, Al-Mn10 intermediate alloy, Al-Zr10 intermediate alloy and Al-Ce5 intermediate alloy are first vacuum smelted and poured according to the composition in Table 17, the smelting temperature of vacuum smelting is 800°C, and the pouring temperature is 750°C, to form an aluminum alloy ingot with a size of 100*100*50.

[0101] (2) After completion, the aluminum alloy ingot is heated to 450°C for high-temperature solid solution for 5h to make all elements uniformly distributed, and then air-cooled to 150°C for multi-pass asynchronous rolling with an initial rolling reduction of 35% and a total deformation of 95% and a non-uniform speed ratio of 1:1.25; after cooling to room temperature, solid solution at 500°C for 30min, then heated to 560°C for solid solution for 2h, and finally solid solution at 500°C for 30min, and finally aging treatment at a temperature of 160°C for 6h, and the tensile strength and elongation of the finally obtained aluminum alloy are shown in Table 18.

[0102] Table 18

[0103] Tensile strength / MPa Tensile strength / MPa Tensile strength / MPa 385 421 14.5％

[0104] Comparative Example 5

[0105] The high-strength and high-toughness aluminum-magnesium-silicon alloy of the present comparative example has the chemical composition shown in Table 19.

[0106] Table 19 Chemical composition of high-strength and high-ductility aluminum-magnesium-silicon alloy (wt%)

[0107]

[0108] A method for preparing a high-strength and high-ductility aluminum-magnesium-silicon alloy includes the following steps:

[0109] (1) Pure Al ingot, pure Mg ingot, Al-Cu60 intermediate alloy, Al-Si20 intermediate alloy, Al-Mn10 intermediate alloy, and Al-Ce5 intermediate alloy are first vacuum smelted and cast according to the components in Table 19, the smelting temperature of vacuum smelting is 800°C, the casting temperature is 750°C, and an aluminum alloy ingot with a size of 100*100*50 is formed.

[0110] (2) After completion, the aluminum alloy ingot is heated to 450°C for 5h of high-temperature solid solution, so that all elements are uniformly distributed, and after air cooling to 150°C, multi-pass asynchronous rolling is performed, the initial rolling reduction is 35%, the total deformation is 95%, and the asynchronous ratio is 1:1.25; after cooling to room temperature, solid solution is performed at 500°C for 30min, then heated to 560°C for 2h of solid solution, and finally solid solution is performed at 500°C for 30min, after water cooling, 1% drawing pre-strain is performed, and finally aging treatment is performed at a temperature of 160°C for 6h, and the tensile strength and elongation of the finally obtained aluminum alloy are shown in Table 20.

[0111] Table 20

[0112] Tensile strength / MPa Tensile strength / MPa Tensile strength / MPa 367 412 13.6％

[0113] Comparative Example 6

[0114] The chemical composition of the high-strength and high-ductility aluminum-magnesium-silicon alloy described in the present comparative example is shown in Table 21.

[0115] Table 21 Chemical composition of high-strength and high-ductility aluminum-magnesium-silicon alloy (wt%)

[0116]

[0117] A method for preparing a high-strength and high-ductility aluminum-magnesium-silicon alloy includes the following steps:

[0118] (1) Pure Al ingot, pure Mg ingot, Al-Cu60 intermediate alloy, Al-Si20 intermediate alloy, Al-Zr10 intermediate alloy, and Al-Ce5 intermediate alloy are first vacuum smelted and cast according to the components in Table 21, the smelting temperature of vacuum smelting is 800°C, the casting temperature is 750°C, and an aluminum alloy ingot with a size of 100*100*50 is formed.

[0119] (2) After completion, the aluminum alloy ingot is heated to 450°C for high-temperature solid solution for 5h, so that all elements are uniformly distributed, and after air cooling to 150°C, multi-pass asynchronous rolling is performed with a primary rolling reduction of 35% and a total deformation of 95% and a non-uniform speed ratio of 1:1.25; after cooling to room temperature, solid solution is performed at 500°C for 30min, then heated to 560°C for solid solution for 2h, finally solid solution at 500°C for 30min, after water cooling, 1% drawing pre-strain is performed, finally aging treatment is performed at a temperature of 160°C for 6h, and the tensile strength and elongation of the finally obtained aluminum alloy are shown in Table 22.

[0120] Table 22

[0121] Tensile strength / MPa Tensile strength / MPa Tensile strength / MPa 351 403 13.1％

[0122] Comparative Example 7

[0123] The high-strength high-toughness aluminum-magnesium-silicon alloy in the present comparative example has the chemical composition shown in Table 23.

[0124] Table 23 Chemical composition of high-strength high-toughness aluminum-magnesium-silicon alloy (wt%)

[0125]

[0126] The preparation method of the high-strength high-toughness aluminum-magnesium-silicon alloy comprises the following steps:

[0127] (1) According to the components in Table 23, pure Al ingot, pure Mg ingot, Al-Si20 intermediate alloy, Al-Mn10 intermediate alloy and Al-Ce5 intermediate alloy are vacuum smelted and cast, the smelting temperature of vacuum smelting is 800°C, and the casting temperature is 750°C, to form an aluminum alloy ingot with a size of 100*100*50.

[0128] (2) After completion, the aluminum alloy ingot is heated to 450°C for high-temperature solid solution for 5h, so that all elements are uniformly distributed, and after air cooling to 150°C, multi-pass asynchronous rolling is performed with a primary rolling reduction of 35% and a total deformation of 95% and a non-uniform speed ratio of 1:1.25; after cooling to room temperature, solid solution is performed at 500°C for 30min, then heated to 560°C for solid solution for 2h, finally solid solution at 500°C for 30min, after water cooling, 1% drawing pre-strain is performed, finally aging treatment is performed at a temperature of 160°C for 6h, and the tensile strength and elongation of the finally obtained aluminum alloy are shown in Table 24.

[0129] Table 24

[0130] Tensile strength / MPa Tensile strength / MPa Tensile strength / MPa Tensile strength / MPa Tensile strength / MPa Tensile strength / MPa Tensile strength / MPa Tensile strength / MPa Tensile strength / MPa Tensile strength / MPa Tensile strength / MPa Tensile strength / MPa Tensile strength / MPa Tensile strength / MPa Tensile strength / MPa Tensile strength / MPa Tensile strength / MPa Tensile strength / MPa Tensile strength / MPa Tensile strength / MPa Tensile strength / MPa Tensile strength / MPa Tensile strength / MPa Tensile strength / MPa Tensile strength / MPa Tensile strength / MPa Tensile strength / MPa Tensile strength / MPa Tensile strength / MPa Tensile strength / MPa Tensile strength 343 376 12.1％

[0131] As can be seen from the comparative examples 1-5 and the comparative examples 1-2, the yield strength, the tensile strength and the elongation of the Al-Mg-Si series aluminum alloy after the multi-pass asynchronous rolling + three-stage solid solution + pre-strain + aging treatment are all improved, especially the strength is most obviously improved. Compared with the aluminum alloy without adding the rare earth Ce and Zr elements or the aluminum alloy obtained by the traditional rolling and heat treatment, the yield strength, the tensile strength and the elongation of the Al-Mg-Si series aluminum alloy after the multi-pass asynchronous rolling + three-stage solid solution + pre-strain + aging treatment are all greatly improved.

[0132] As can be seen from the example 1 and the comparative example 3, the performance of the aluminum alloy obtained by the three-stage solid solution heat treatment is greatly improved than that of the alloy obtained by only one-stage solid solution. In the three-stage solid solution process, the precipitated phase containing Mg and Si elements and having a low solid solution temperature is firstly solid-solved into the matrix at a low temperature, when the temperature is increased, the precipitated phase containing Cu, Ce and Zr elements and having a high solid solution temperature is solid-solved into the matrix at a high temperature, and then the low-temperature solid solution is performed again to make the structure and composition of the alloy more uniform. Through the three-stage solid solution, the rare earth element Ce and the alloy element Zr can better form the dispersed phase to pin the dislocation and the grain boundary, the subgrain boundary, and better dispersion strengthening and substructure strengthening effects are achieved.

[0133] As can be seen from the example and the comparative example 4, the strength of the material can be improved by applying a certain pre-strain to the material after the solid solution. This is mainly because after the pre-strain is applied, a certain dislocation is generated in the material, and in the subsequent aging process, the dislocation and the dispersed phase pinning the grain boundary together act to make the grain growth and the precipitation and growth of the precipitated phase difficult, and at the same time, more nucleation sites are provided for the precipitation of the precipitated phase, the content of the precipitated phase is increased, and the strength of the aluminum alloy is enhanced.

[0134] As can be seen from the example and the comparative examples 5-7, when the alloy lacks the elements such as Cu, Ce or Zr, even if the preparation method of “multi-pass asynchronous rolling + three-stage solid solution + pre-strain + aging treatment” is used, the mechanical properties of the material cannot be improved. This is because the addition of the Cu element can form the Cu-containing phase (QP1, QP2, Q) in the alloy, and these new precipitated phases can improve the peak strength and toughness of the aluminum alloy; the addition of the Zr element can generate the primary Al3Zr particles in the alloy, which can act as the heterogeneous nucleation core in the solidification process and can significantly refine the grains; the addition of the Ce rare earth element can make the Ce element adsorbed on the surface of the eutectic Si phase to form a large number of twins, and the presence of the Ce element can also form the alloy phase with the Si, Cu and Mn elements in the alloy to hinder the growth of the α-Al phase in the solidification process; thereby the grains are refined. Moreover, after the treatment of the multi-pass asynchronous rolling + three-stage solid solution + pre-strain + aging treatment, the strengthening effect caused by the alloy elements is further improved.

[0135] In summary, the aluminum alloy of the present application adds Cu, Zr, Ce and other elements in composition, and adopts a processing method of multi-pass asynchronous rolling + three-stage solid solution + pre-strain + aging treatment. The addition of Cu element forms Cu-containing phases (QP1, QP2, Q) in the alloy, the addition of Zr element generates primary Al3Zr particles in the alloy, which can act as heterogeneous nucleation cores in the solidification process, the addition of Ce rare earth element makes the Ce element adsorb on the surface of eutectic Si phase to form a large number of twin crystals, and the presence of Ce element also forms alloy phases with Si, Cu, Mn and other elements in the alloy to hinder the growth of α-Al phase in the solidification process. After asynchronous rolling + three-stage solid solution + pre-aging treatment, the Cu, Zr and Ce-containing precipitates are more uniformly distributed and the number is more, which can provide a large number of nucleation sites for the formation of strengthening phases (Mg2Si) in the aluminum alloy, reduce the nucleation work of Mg2Si, and hinder the further growth of grains in the aluminum alloy. The alloy composition and preparation method jointly refine the grains and increase the precipitates, so that the strength and toughness of the aluminum alloy are greatly improved.

[0136] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application and not to limit the scope of protection of the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present application.

Claims

1. A method for producing a high-strength high-ductility aluminum-magnesium-silicon alloy, characterized by comprising: The mechanical properties of the high-strength and high-toughness aluminum magnesium silicon alloy are enhanced by optimizing the composition of the high-strength and high-toughness aluminum magnesium silicon alloy, combining multi-pass asynchronous rolling, three-stage solid solution, pre-strain and aging treatment, including the following steps: ​ (1) proportioning raw materials according to the proportion of pure Al ingot, pure Mg ingot, Al-60Cu intermediate alloy, Al-20Si intermediate alloy, Al-10Mn intermediate alloy, Al-10Zr intermediate alloy and Al-5Ce intermediate alloy, melting and pouring to obtain an aluminum alloy ingot; (2) homogenizing the aluminum alloy ingot to obtain a homogenized ingot; (3) multi-pass asynchronous rolling of the homogenized ingot, followed by three-stage solid solution, pre-strain and aging treatment to obtain a high-strength and high-toughness aluminum magnesium silicon alloy; The temperature of the multi-pass asynchronous rolling is 150-200 DEG C, the rolling speed is 0.5-1.2 m / s, the total deformation is 75-95%, the initial rolling reduction is 35-50%, and the asynchronous ratio is 1:1.25-1:1.5; The three-stage solid solution is as follows: the first-stage solid solution temperature is 500-525 DEG C, the time is 0.5-2 h; the second-stage solid solution temperature is 540-565 DEG C, the time is 0.5-2 h; and the third-stage solid solution temperature is 500-525 DEG C, the time is 0.5-2 h; The high-strength and high-toughness aluminum magnesium silicon alloy comprises the following components by mass percentage: Si: 0.6-1.1%, Mg: 0.5-1.0%, Mn: 0.2-0.5%, Cu: 0.5-1.3%, Zr: 0.15-0.5%, Ce: 0.15-0.5%, and the total content of unavoidable impurities is less than 0.2%; and the balance is Al.

2. The method of producing a high-strength high-ductility Al-Mg-Si alloy according to claim 1, wherein The pre-strain is drawing, rolling or extrusion, and the strain rate is 1-5%.

3. The preparation method of the high-strength, high-toughness aluminum-magnesium-silicon alloy as described in claim 1, characterized in that, The aging treatment temperature is 140-185 DEG C, and the time is 6-24 h.

4. The method of producing a high-strength high-ductility Al-Mg-Si alloy according to claim 1, wherein The homogenization treatment temperature is 450-550 DEG C, and the holding time is 3-5 h.

5. The method for preparing the high-strength, high-toughness aluminum-magnesium-silicon alloy as described in claim 1, characterized in that, The melting temperature is 800-850 DEG C, and the pouring temperature is 650-750 DEG C.

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