阅读说明：本技术 一种提高铝合金强韧性的热处理方法 (Heat treatment method for improving toughness of aluminum alloy ) 是由 刘光磊 薛文超 丁冉 孙小轩 陶诚 吕鹏 郭顺 刘海霞 程晓农 于 2021-07-02 设计创作，主要内容包括：本发明一种提高铝合金强韧性的热处理方法,属于铝合金制备技术领域,材料为连续铸造铝合金板材,先要在545～555℃进行均匀化处理,处理时间与板材厚度有密切关系并建立模型；然后进行固溶处理,要求在525～535℃下保温40～50min,立即水冷至室温；接着进行拉伸处理以去除应力,拉伸率控制在2.4～2.6％；最后进行时效处理,在160～170℃保温7.5～8.5h后空冷即可。该方法可以显著提升铝合金板材的力学性能,抗拉强度提升5～10％,屈服强度提升10～15％,伸长率提升在50％以上,有效降低板材厚度对性能的不利影响。(The invention relates to a heat treatment method for improving the strength and toughness of an aluminum alloy, which belongs to the technical field of aluminum alloy preparation, wherein a material is a continuously cast aluminum alloy plate, homogenization treatment is firstly carried out at 545-555 ℃, the treatment time and the plate thickness have a close relation, and a model is established; then carrying out solution treatment, preserving the heat for 40-50 min at the temperature of 525-535 ℃, and immediately cooling to room temperature by water; then, stretching treatment is carried out to remove stress, and the stretching rate is controlled to be 2.4-2.6%; and finally, carrying out aging treatment, and carrying out air cooling after heat preservation for 7.5-8.5 h at 160-170 ℃. The method can obviously improve the mechanical property of the aluminum alloy plate, the tensile strength is improved by 5-10%, the yield strength is improved by 10-15%, the elongation is improved by more than 50%, and the adverse effect of the thickness of the plate on the property is effectively reduced.)

1. A heat treatment method for improving the obdurability of an aluminum alloy is characterized by comprising the following steps:

(1) the material is a continuously cast aluminum alloy plate:

the chemical components of the alloy comprise, by mass, 0.90-0.96% of Si, 0.6-0.8% of Mg, 0.5-0.6% of Mn, 0.15-0.2% of composite rare earth, 0.01-0.03% of Ti, 0.00-0.05% of Ni, 0.00-0.05% of Cr, 0.00-0.05% of Zn, 0.00-0.04% of Cu, 0.001-0.005% of B, 0.15-0.25% of Fe, 0.00-0.15% of other elements and the balance of Al;

(2) homogenizing:

and (3) air cooling after heat preservation is carried out for a certain time at the temperature of 545-555 ℃, wherein the heat preservation time Y and the plate thickness X are in accordance with the following model:

when X belongs to [8,11], Y is 6 XX;

② when X belongs to (11, 13), Y is 5 XX;

(iii) when X ∈ (13, 20), Y ═ 4.5 × X;

when X belongs to (20, 25), Y is 4 XX;

when X belongs to (25, 38), Y is 3.75 XX;

wherein, Y, heat preservation time and unit min; x, the thickness of the plate in mm;

(3) solution treatment:

preserving the heat for 40-50 min at the temperature of 525-535 ℃, and immediately cooling to room temperature by water;

(4) stretching treatment:

the stress is removed, and the tensile rate is controlled to be 2.4-2.6%;

(5) aging treatment:

keeping the temperature at 160-170 ℃ for 7.5-8.5 h, and then air cooling.

2. The heat treatment method for improving the toughness of the aluminum alloy according to claim 1, wherein in the step (1), the chemical components of the composite rare earth comprise, by mass, 22-27% of Ce, 8-12% of Nd, 8-12% of Er, 5-8% of Sc, 5-8% of Y, 2-5% of Pr, 2-5% of Ho, 2-5% of Lu and the balance La.

3. The heat treatment method for improving the toughness of the aluminum alloy according to the claim 1 or 2, wherein in the step (1), the chemical composition of the composite rare earth comprises, by mass, 24% of Ce, 10% of Nd, 10% of Er, 6.5% of Sc, 6.5% of Y, 3% of Pr, 3% of Ho, 3% of Lu and the balance La.

4. The heat treatment method for improving the toughness of an aluminum alloy according to claim 1, wherein in the step (1), the chemical composition of the continuously cast aluminum alloy sheet is, in mass percent, 0.93% of Si, 0.7% of Mg, 0.55% of Mn, 0.17% of a rare earth complex, 0.02% of Ti, 0.02% of Ni, 0.02% of Cr, 0.02% of Zn, 0.02% of Cu, 0.002% of B, 0.2% of Fe, 0.00 to 0.15% of other elements, and the balance of Al.

5. The heat treatment method for improving the toughness of the aluminum alloy according to claim 1 or 4, wherein in the step (1), the mass percent of single element in the other elements is 0.00-0.05%.

6. The heat treatment method for improving the toughness of the aluminum alloy according to claim 1, wherein in the step (2), the homogenization treatment temperature is 550 ℃.

7. The heat treatment method for improving the toughness of the aluminum alloy according to claim 1, wherein in the step (3), the solution treatment temperature is 530 ℃ and the holding time is 45 min.

8. The heat treatment method for improving the toughness of an aluminum alloy according to claim 1, wherein in the step (4), the elongation of the stretching treatment is 2.5%.

9. The heat treatment method for improving the toughness of the aluminum alloy according to claim 1, wherein in the step (5), the aging temperature is 165 ℃ and the holding time is 8 h.

Technical Field

The invention belongs to the technical field of aluminum alloy strengthening, and particularly relates to a heat treatment method for improving the strength and toughness of an aluminum alloy.

Background

In order to deal with the increasingly prominent problems of contradiction between fuel supply and demand and environmental pollution, major industrial countries in the world are increasingly deployed and promoted to develop towards light weight. Taking a new energy automobile as an example, the mass of the automobile is reduced by 10%, the corresponding endurance mileage is increased by 5-10%, and 15-20% of battery cost and 20% of daily loss cost are saved. Therefore, the light weight is just an important technical path and development core problem for energy conservation and consumption reduction in the industrial fields of new energy automobiles and the like.

The aluminum and the aluminum alloy have a series of excellent characteristics of light weight, wear resistance, corrosion resistance, good elasticity, high specific strength and specific rigidity, good impact resistance, easy surface coloring, good processing formability, extremely high recycling and regeneration performance and the like. The carbon fiber composite material, the aluminum alloy and the high-strength steel are adopted to replace the low-carbon steel which is the current mainstream material, the weight can be reduced by 60 percent, 40 percent and 25 percent respectively, the weight reduction effect and the production cost are comprehensively evaluated, and the aluminum alloy is the most core, reliable and promising material. However, aluminum alloys are different from steel phase transformation strengthening mechanism materials, so that the performance of aluminum alloy materials can be improved only by solid solution strengthening, precipitation strengthening, excess phase strengthening, fine grain strengthening and deformation strengthening. With the continuous progress of industry, in order to meet the requirements of industrial application on high strength and high toughness of aluminum alloy, the practical production usually adopts T6, namely solid solution and aging heat treatment strengthening or deformation and T6 composite strengthening, so that the problems of uneven aluminum alloy components, coarse grains, large residual stress and the like are easily caused, and the cracking phenomenon occurs in the subsequent production and processing process of the aluminum alloy plate. Based on the method, the invention develops a heat treatment method for improving the obdurability of the aluminum alloy.

Disclosure of Invention

The invention develops a heat treatment method for improving the obdurability of an aluminum alloy, which is carried out according to the following steps:

(1) the material is a continuously cast aluminum alloy plate, and the chemical components of the continuously cast aluminum alloy plate are, by mass, 0.90-0.96% of Si, 0.6-0.8% of Mg, 0.5-0.6% of Mn, 0.15-0.2% of composite rare earth, 0.01-0.03% of Ti, 0.00-0.05% of Ni, 0.00-0.05% of Cr, 0.00-0.05% of Zn, 0.00-0.04% of Cu, 0.001-0.005% of B, 0.15-0.25% of Fe, 0.00-0.15% of other elements (wherein a single element is 0.00-0.05%), and the balance of Al.

Wherein, the chemical components of the composite rare earth are as follows: 22-27% of Ce, 8-12% of Nd, 8-12% of Er, 5-8% of Sc, 5-8% of Y, 2-5% of Pr, 2-5% of Ho, 2-5% of Lu and the balance of La.

(2) And (6) homogenizing. Keeping the temperature of 545-555 ℃ for a certain time, and then carrying out air cooling, wherein the heat preservation time (Y, min) and the plate thickness (X, mm) are in accordance with the following rules:

when X belongs to [8,11], Y is 6 XX;

② when X belongs to (11, 13), Y is 5 XX;

(iii) when X ∈ (13, 20), Y ═ 4.5 × X;

when X belongs to (20, 25), Y is 4 XX;

and when X belongs to (25, 38), Y is 3.75 XX.

(3) And (4) solution treatment. Preserving the heat for 40-50 min at 525-535 ℃, and immediately cooling to room temperature by water.

(4) And (5) stretching treatment. The stress is removed, the tensile rate is controlled to be 2.4-2.6%, and the tensile rate calculation method comprises the following steps:

(5) and (5) aging treatment. Keeping the temperature at 160-170 ℃ for 7.5-8.5 h, and then air cooling.

In the step (1), the preferable chemical components (mass percent) of the continuously cast aluminum alloy plate are as follows: 0.93% of Si, 0.7% of Mg, 0.55% of Mn, 0.17% of composite rare earth, 0.02% of Ti, 0.02% of Ni, 0.02% of Cr, 0.02% of Zn, 0.02% of Cu, 0.002% of B, 0.2% of Fe, 0.00-0.15% of other elements (wherein, the single element is 0.00-0.05%), and the balance of Al.

In the step (1), the preferable chemical components of the composite rare earth are as follows: 24% of Ce, 10% of Nd, 10% of Er, 6.5% of Sc, 6.5% of Y, 3% of Pr, 3% of Ho, 3% of Lu and the balance of La.

Wherein the homogenization treatment temperature in step (2) is preferably 550 ℃.

Wherein the solution treatment temperature in the step (3) is preferably 530 ℃, and the holding time is preferably 45 min.

Wherein the stretching ratio of the stretching treatment described in the step (4) is preferably 2.5%.

Wherein the aging treatment temperature in the step (5) is preferably 165 ℃, and the holding time is preferably 8 h.

Drawings

FIG. 1 tensile specimen shape and size

Detailed Description

The mechanical property test is carried out on a DDL-100 electronic universal tester. As shown in FIG. 1, the tensile specimen was sampled and processed at an intermediate position in the thickness direction of the plate material by wire cutting. The tensile rate in the experiment was 2mm/min and the average was taken 4 times per sample measurement.

Example 1

The material is a continuously cast aluminum alloy plate with the thickness of 10mm, and the material comprises, by mass, 0.90% of Si, 0.6% of Mg, 0.5% of Mn, 0.15% of composite rare earth, 0.01% of Ti, 0% of Ni, 0% of Cr, 0% of Zn, 0% of Cu, 0.001% of B, 0.15% of Fe, 0.00-0.15% of other elements (wherein, the single element is 0.00-0.05%), and the balance of Al. Wherein, the chemical components of the composite rare earth are as follows: 22% of Ce, 8% of Nd, 8% of Er, 5% of Sc, 5% of Y, 2% of Pr, 2% of Ho, 2% of Lu and the balance of La. Homogenizing: keeping the temperature at 545 ℃ for 60min and then cooling in air. Solution treatment: the temperature is kept at 525 ℃ for 40min, and the temperature is immediately cooled to room temperature by water. Stretching treatment: the elongation was controlled to 2.4%. Aging treatment: keeping the temperature at 160-170 ℃ for 7.5h, and then air cooling. The mechanical property of the aluminum alloy prepared by the process method is tested, the method is detailed in a specific embodiment, and the experimental result is shown in table 1.

Example 2

The material is a continuously cast aluminum alloy plate with the thickness of 10mm, and comprises the chemical components of, by mass, 0.96% of Si, 0.8% of Mg, 0.6% of Mn, 0.2% of composite rare earth, 0.03% of Ti, 0.05% of Ni, 0.05% of Cr, 0.05% of Zn, 0.04% of Cu, 0.005% of B, 0.25% of Fe, 0.00-0.15% of other elements (wherein the single element is 0.00-0.05%), and the balance of Al. Wherein, the chemical components of the composite rare earth are as follows: 27% of Ce, 12% of Nd, 12% of Er, 8% of Sc, 8% of Y, 5% of Pr, 5% of Ho, 5% of Lu and the balance of La. Homogenizing: keeping the temperature at 555 ℃ for 60min, and then cooling in air. Solution treatment: the temperature is kept at 535 ℃ for 50min, and the mixture is immediately cooled to room temperature by water. Stretching treatment: the elongation was controlled to 2.6%. Aging treatment: keeping the temperature at 170 ℃ for 8.5h, and then cooling in air. The mechanical property of the aluminum alloy prepared by the process method is tested, the method is detailed in a specific embodiment, and the experimental result is shown in table 1.

Example 3

The material is a continuously cast aluminum alloy plate with the thickness of 10mm, and comprises the chemical components of, by mass, 0.93% of Si, 0.7% of Mg, 0.55% of Mn, 0.17% of composite rare earth, 0.02% of Ti, 0.02% of Ni, 0.02% of Cr, 0.02% of Zn, 0.02% of Cu, 0.002% of B, 0.2% of Fe, 0.00-0.15% of other elements (wherein the single element is 0.00-0.05%), and the balance of Al. Wherein, the chemical components of the composite rare earth are as follows: 24% of Ce, 10% of Nd, 10% of Er, 6.5% of Sc, 6.5% of Y, 3% of Pr, 3% of Ho, 3% of Lu and the balance of La. Homogenizing: keeping the temperature at 550 ℃ for 60min, and then cooling in air. Solution treatment: keeping the temperature at 530 ℃ for 45min, and immediately cooling to room temperature by water. Stretching treatment: the elongation was controlled to 2.5%. Aging treatment: keeping the temperature at 165 ℃ for 8h, and then cooling in air. The mechanical property of the aluminum alloy prepared by the process method is tested, the method is detailed in a specific embodiment, and the experimental result is shown in table 1.

Example 4

The material is a continuously cast aluminum alloy plate with the thickness of 16mm, and comprises the chemical components of, by mass, 0.90% of Si, 0.6% of Mg, 0.5% of Mn, 0.15% of composite rare earth, 0.01% of Ti, 0% of Ni, 0% of Cr, 0% of Zn, 0% of Cu, 0.001% of B, 0.15% of Fe, 0.00-0.15% of other elements (wherein, the single element is 0.00-0.05%), and the balance of Al. Wherein, the chemical components of the composite rare earth are as follows: 22% of Ce, 8% of Nd, 8% of Er, 5% of Sc, 5% of Y, 2% of Pr, 2% of Ho, 2% of Lu and the balance of La. Homogenizing: keeping the temperature at 545 ℃ for 72min, and then cooling in air. Solution treatment: the temperature is kept at 525 ℃ for 40min, and the temperature is immediately cooled to room temperature by water. Stretching treatment: the elongation was controlled to 2.4%. Aging treatment: keeping the temperature at 160-170 ℃ for 7.5h, and then air cooling. The mechanical property of the aluminum alloy prepared by the process method is tested, the method is detailed in a specific embodiment, and the experimental result is shown in table 1.

Example 5

The material is a continuously cast aluminum alloy plate with the thickness of 16mm, and comprises the chemical components of, by mass, 0.96% of Si, 0.8% of Mg, 0.6% of Mn, 0.2% of composite rare earth, 0.03% of Ti, 0.05% of Ni, 0.05% of Cr, 0.05% of Zn, 0.04% of Cu, 0.005% of B, 0.25% of Fe, 0.00-0.15% of other elements (wherein the single element is 0.00-0.05%), and the balance of Al. Wherein, the chemical components of the composite rare earth are as follows: 27% of Ce, 12% of Nd, 12% of Er, 8% of Sc, 8% of Y, 5% of Pr, 5% of Ho, 5% of Lu and the balance of La. Homogenizing: keeping the temperature at 555 ℃ for 72min, and then cooling in air. Solution treatment: the temperature is kept at 535 ℃ for 50min, and the mixture is immediately cooled to room temperature by water. Stretching treatment: the elongation was controlled to 2.6%. Aging treatment: keeping the temperature at 170 ℃ for 8.5h, and then cooling in air. The mechanical property of the aluminum alloy prepared by the process method is tested, the method is detailed in a specific embodiment, and the experimental result is shown in table 1.

Example 6

The material is a continuously cast aluminum alloy plate with the thickness of 16mm, and comprises the chemical components of, by mass, 0.93% of Si, 0.7% of Mg, 0.55% of Mn, 0.17% of composite rare earth, 0.02% of Ti, 0.02% of Ni, 0.02% of Cr, 0.02% of Zn, 0.02% of Cu, 0.002% of B, 0.2% of Fe, 0.00-0.15% of other elements (wherein the single element is 0.00-0.05%), and the balance of Al. Wherein, the chemical components of the composite rare earth are as follows: 24% of Ce, 10% of Nd, 10% of Er, 6.5% of Sc, 6.5% of Y, 3% of Pr, 3% of Ho, 3% of Lu and the balance of La. Homogenizing: keeping the temperature at 550 ℃ for 72min, and then cooling in air. Solution treatment: keeping the temperature at 530 ℃ for 45min, and immediately cooling to room temperature by water. Stretching treatment: the elongation was controlled to 2.5%. Aging treatment: keeping the temperature at 165 ℃ for 8h, and then cooling in air. The mechanical property of the aluminum alloy prepared by the process method is tested, the method is detailed in a specific embodiment, and the experimental result is shown in table 1.

Example 7

The material is a continuously cast aluminum alloy plate with the thickness of 22mm, and the material comprises, by mass, 0.90% of Si, 0.6% of Mg, 0.5% of Mn, 0.15% of composite rare earth, 0.01% of Ti, 0% of Ni, 0% of Cr, 0% of Zn, 0% of Cu, 0.001% of B, 0.15% of Fe, 0.00-0.15% of other elements (wherein, the single element is 0.00-0.05%), and the balance of Al. Wherein, the chemical components of the composite rare earth are as follows: 22% of Ce, 8% of Nd, 8% of Er, 5% of Sc, 5% of Y, 2% of Pr, 2% of Ho, 2% of Lu and the balance of La. Homogenizing: keeping the temperature at 545 ℃ for 88min, and then cooling in air. Solution treatment: the temperature is kept at 525 ℃ for 40min, and the temperature is immediately cooled to room temperature by water. Stretching treatment: the elongation was controlled to 2.4%. Aging treatment: keeping the temperature at 160-170 ℃ for 7.5h, and then air cooling. The mechanical property of the aluminum alloy prepared by the process method is tested, the method is detailed in a specific embodiment, and the experimental result is shown in table 1.

Example 8

The material is a continuously cast aluminum alloy plate with the thickness of 22mm, and comprises the chemical components of, by mass, 0.96% of Si, 0.8% of Mg, 0.6% of Mn, 0.2% of composite rare earth, 0.03% of Ti, 0.05% of Ni, 0.05% of Cr, 0.05% of Zn, 0.04% of Cu, 0.005% of B, 0.25% of Fe, 0.00-0.15% of other elements (wherein the single element is 0.00-0.05%), and the balance of Al. Wherein, the chemical components of the composite rare earth are as follows: 27% of Ce, 12% of Nd, 12% of Er, 8% of Sc, 8% of Y, 5% of Pr, 5% of Ho, 5% of Lu and the balance of La. Homogenizing: keeping the temperature at 555 ℃ for 88min, and then cooling in air. Solution treatment: the temperature is kept at 535 ℃ for 50min, and the mixture is immediately cooled to room temperature by water. Stretching treatment: the elongation was controlled to 2.6%. Aging treatment: keeping the temperature at 170 ℃ for 8.5h, and then cooling in air. The mechanical property of the aluminum alloy prepared by the process method is tested, the method is detailed in a specific embodiment, and the experimental result is shown in table 1.

Example 9

The material is a continuously cast aluminum alloy plate with the thickness of 22mm, and comprises the chemical components of, by mass, 0.93% of Si, 0.7% of Mg, 0.55% of Mn, 0.17% of composite rare earth, 0.02% of Ti, 0.02% of Ni, 0.02% of Cr, 0.02% of Zn, 0.02% of Cu, 0.002% of B, 0.2% of Fe, 0.00-0.15% of other elements (wherein the single element is 0.00-0.05%), and the balance of Al. Wherein, the chemical components of the composite rare earth are as follows: 24% of Ce, 10% of Nd, 10% of Er, 6.5% of Sc, 6.5% of Y, 3% of Pr, 3% of Ho, 3% of Lu and the balance of La. Homogenizing: keeping the temperature at 550 ℃ for 88min, and then cooling in air. Solution treatment: keeping the temperature at 530 ℃ for 45min, and immediately cooling to room temperature by water. Stretching treatment: the elongation was controlled to 2.5%. Aging treatment: keeping the temperature at 165 ℃ for 8h, and then cooling in air. The mechanical property of the aluminum alloy prepared by the process method is tested, the method is detailed in a specific embodiment, and the experimental result is shown in table 1.

Example 10

The material is a continuously cast aluminum alloy plate with the thickness of 30mm, and the material comprises, by mass, 0.90% of Si, 0.6% of Mg, 0.5% of Mn, 0.15% of composite rare earth, 0.01% of Ti, 0% of Ni, 0% of Cr, 0% of Zn, 0% of Cu, 0.001% of B, 0.15% of Fe, 0.00-0.15% of other elements (wherein, the single element is 0.00-0.05%), and the balance of Al. Wherein, the chemical components of the composite rare earth are as follows: 22% of Ce, 8% of Nd, 8% of Er, 5% of Sc, 5% of Y, 2% of Pr, 2% of Ho, 2% of Lu and the balance of La. Homogenizing: keeping the temperature at 545 ℃ for 112.5min, and then cooling in air. Solution treatment: the temperature is kept at 525 ℃ for 40min, and the temperature is immediately cooled to room temperature by water. Stretching treatment: the elongation was controlled to 2.4%. Aging treatment: keeping the temperature at 160-170 ℃ for 7.5h, and then air cooling. The mechanical property of the aluminum alloy prepared by the process method is tested, the method is detailed in a specific embodiment, and the experimental result is shown in table 1.

Example 11

The material is a continuously cast aluminum alloy plate with the thickness of 30mm, and comprises the chemical components of, by mass, 0.96% of Si, 0.8% of Mg, 0.6% of Mn, 0.2% of composite rare earth, 0.03% of Ti, 0.05% of Ni, 0.05% of Cr, 0.05% of Zn, 0.04% of Cu, 0.005% of B, 0.25% of Fe, 0.00-0.15% of other elements (wherein the single element is 0.00-0.05%), and the balance of Al. Wherein, the chemical components of the composite rare earth are as follows: 27% of Ce, 12% of Nd, 12% of Er, 8% of Sc, 8% of Y, 5% of Pr, 5% of Ho, 5% of Lu and the balance of La. Homogenizing: keeping the temperature at 555 ℃ for 112.5min, and then cooling in air. Solution treatment: the temperature is kept at 535 ℃ for 50min, and the mixture is immediately cooled to room temperature by water. Stretching treatment: the elongation was controlled to 2.6%. Aging treatment: keeping the temperature at 170 ℃ for 8.5h, and then cooling in air. The mechanical property of the aluminum alloy prepared by the process method is tested, the method is detailed in a specific embodiment, and the experimental result is shown in table 1.

Example 12

The material is a continuously cast aluminum alloy plate with the thickness of 30mm, and comprises the chemical components of, by mass, 0.93% of Si, 0.7% of Mg, 0.55% of Mn, 0.17% of composite rare earth, 0.02% of Ti, 0.02% of Ni, 0.02% of Cr, 0.02% of Zn, 0.02% of Cu, 0.002% of B, 0.2% of Fe, 0.00-0.15% of other elements (wherein the single element is 0.00-0.05%), and the balance of Al. Wherein, the chemical components of the composite rare earth are as follows: 24% of Ce, 10% of Nd, 10% of Er, 6.5% of Sc, 6.5% of Y, 3% of Pr, 3% of Ho, 3% of Lu and the balance of La. Homogenizing: keeping the temperature at 550 ℃ for 112.5min, and then cooling in air. Solution treatment: keeping the temperature at 530 ℃ for 45min, and immediately cooling to room temperature by water. Stretching treatment: the elongation was controlled to 2.5%. Aging treatment: keeping the temperature at 165 ℃ for 8h, and then cooling in air. The mechanical property of the aluminum alloy prepared by the process method is tested, the method is detailed in a specific embodiment, and the experimental result is shown in table 1.

Comparative example 1

The material is a continuously cast aluminum alloy plate with the thickness of 10mm, and comprises the chemical components of, by mass, 0.93% of Si, 0.7% of Mg, 0.55% of Mn, 0.17% of composite rare earth, 0.02% of Ti, 0.02% of Ni, 0.02% of Cr, 0.02% of Zn, 0.02% of Cu, 0.002% of B, 0.2% of Fe, 0.00-0.15% of other elements (wherein the single element is 0.00-0.05%), and the balance of Al. Wherein, the chemical components of the composite rare earth are as follows: 24% of Ce, 10% of Nd, 10% of Er, 6.5% of Sc, 6.5% of Y, 3% of Pr, 3% of Ho, 3% of Lu and the balance of La. Solution treatment: keeping the temperature at 530 ℃ for 45min, and immediately cooling to room temperature by water. Aging treatment: keeping the temperature at 165 ℃ for 8h, and then cooling in air. The mechanical property of the aluminum alloy prepared by the process method is tested, the method is detailed in a specific embodiment, and the experimental result is shown in table 1.

Comparative example 2

The material is a continuously cast aluminum alloy plate with the thickness of 16mm, and comprises the chemical components of, by mass, 0.93% of Si, 0.7% of Mg, 0.55% of Mn, 0.17% of composite rare earth, 0.02% of Ti, 0.02% of Ni, 0.02% of Cr, 0.02% of Zn, 0.02% of Cu, 0.002% of B, 0.2% of Fe, 0.00-0.15% of other elements (wherein the single element is 0.00-0.05%), and the balance of Al. Wherein, the chemical components of the composite rare earth are as follows: 24% of Ce, 10% of Nd, 10% of Er, 6.5% of Sc, 6.5% of Y, 3% of Pr, 3% of Ho, 3% of Lu and the balance of La. Solution treatment: keeping the temperature at 530 ℃ for 45min, and immediately cooling to room temperature by water. Aging treatment: keeping the temperature at 165 ℃ for 8h, and then cooling in air. The mechanical property of the aluminum alloy prepared by the process method is tested, the method is detailed in a specific embodiment, and the experimental result is shown in table 1.

Comparative example 3

The material is a continuously cast aluminum alloy plate with the thickness of 22mm, and comprises the chemical components of, by mass, 0.93% of Si, 0.7% of Mg, 0.55% of Mn, 0.17% of composite rare earth, 0.02% of Ti, 0.02% of Ni, 0.02% of Cr, 0.02% of Zn, 0.02% of Cu, 0.002% of B, 0.2% of Fe, 0.00-0.15% of other elements (wherein the single element is 0.00-0.05%), and the balance of Al. Wherein, the chemical components of the composite rare earth are as follows: 24% of Ce, 10% of Nd, 10% of Er, 6.5% of Sc, 6.5% of Y, 3% of Pr, 3% of Ho, 3% of Lu and the balance of La. Solution treatment: keeping the temperature at 530 ℃ for 45min, and immediately cooling to room temperature by water. Aging treatment: keeping the temperature at 165 ℃ for 8h, and then cooling in air. The mechanical property of the aluminum alloy prepared by the process method is tested, the method is detailed in a specific embodiment, and the experimental result is shown in table 1.

Comparative example 4

The material is a continuously cast aluminum alloy plate with the thickness of 30mm, and comprises the chemical components of, by mass, 0.93% of Si, 0.7% of Mg, 0.55% of Mn, 0.17% of composite rare earth, 0.02% of Ti, 0.02% of Ni, 0.02% of Cr, 0.02% of Zn, 0.02% of Cu, 0.002% of B, 0.2% of Fe, 0.00-0.15% of other elements (wherein the single element is 0.00-0.05%), and the balance of Al. Wherein, the chemical components of the composite rare earth are as follows: 24% of Ce, 10% of Nd, 10% of Er, 6.5% of Sc, 6.5% of Y, 3% of Pr, 3% of Ho, 3% of Lu and the balance of La. Solution treatment: keeping the temperature at 530 ℃ for 45min, and immediately cooling to room temperature by water. Aging treatment: keeping the temperature at 165 ℃ for 8h, and then cooling in air. The mechanical property of the aluminum alloy prepared by the process method is tested, the method is detailed in a specific embodiment, and the experimental result is shown in table 1.

The experimental result is shown in table 1, compared with the solid solution and aging heat treatment adopted by enterprises currently, the mechanical property of the aluminum alloy plate can be effectively improved by adopting the method provided by the invention, the tensile strength is improved by 5-10%, the yield strength is improved by 10-15%, the elongation is improved by more than 50%, and the stability of the performance is better and more reliable no matter the thickness of the plate is changed.

TABLE 1 mechanical Properties of aluminum alloy sheets of different thicknesses