Ultrahigh-strength medium-low deformation resistance aluminum alloy profile and preparation and application thereof

Abstract

The invention relates to the technical field of preparation of aluminum alloy profiles, and discloses an ultrahigh-strength medium-low deformation resistance aluminum alloy profile and preparation and application thereof, the ultrahigh-strength medium-low deformation resistance aluminum alloy profile comprises the following alloy components in percentage by weight: 2.0%-3.0% of Mg, 0.8%-1.4% of Si, 3.0%-4.5% of Zn, less than 0.3% of Fe, 0.1%-0.3% of Mn, 0.4%-0.8% of Cu, 0.05%-0.20% of La, 0.05%-0.20% of Sn, 0.05%-0.20% of Zr, 0.3%-0.5% of Mn + La + Zr and the balance of Al. Through double superposition strengthening of ZnMgCu and MgSi, the mechanical property of the material can be greatly improved, and the limitation that traditional 6-series and 7-series alloys only use a single-component strengthening phase is broken through. And meanwhile, the unique aging treatment process avoids corrosion resistance reduction caused by high Zn, the deformation resistance improvement effect caused by solid solution of Mg and Cu elements in the alloy during high-temperature extrusion is reduced, and the extrudable performance of the material is greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of the preparation of aluminum alloy profiles, and particularly relates to an ultra-high-strength aluminum alloy profile with low deformation resistance and its preparation and application. Background Art

[0002] Due to its advantages such as low density, high specific strength, and good corrosion resistance, aluminum alloy has been widely used in the fields of automobiles, rail transit, aerospace, etc. However, the existing 6-series and 7-series aluminum alloys can only improve the strength through a single-component strengthening phase, and the strengthening effect is limited. At the same time, a high Zn content will lead to a decrease in corrosion resistance, while high Mg and Cu contents will lead to an increase in deformation resistance and a decrease in extrudability. Therefore, the existing aluminum alloys cannot achieve the goals of ultra-high strength, good corrosion resistance, and low deformation resistance at the same time, and it is urgent to develop new aluminum alloys to meet the requirements of lightweight automotive parts.

[0003] Some existing 6-series and 7-series aluminum alloys and their preparations can be referred to the Chinese invention patent documents with publication numbers CN118006975A, CN107675048A, and CN114790528A. Summary of the Invention

[0004] Aiming at the problems existing in the prior art, the purpose of the present invention is to provide an aluminum alloy profile and its preparation method that can simultaneously meet the requirements of ultra-high strength, low deformation resistance, and good corrosion resistance, which is beneficial to the production of aluminum alloy profiles with complex cross-sections, and further to solve one or more technical problems existing in the prior art, and at least provide a beneficial choice or create conditions.

[0005] To achieve the above purpose, the present invention adopts the following technical solutions.

[0006] A preparation method of an ultra-high-strength aluminum alloy profile with low deformation resistance, and its preparation steps are as follows:

[0007] 1) Prepare an aluminum rod, and the alloy composition of the aluminum rod is: Mg content 2.0% - 3.0%, Si content 0.8% - 1.4%, Zn content 3.0 - 4.5%, Fe content less than 0.3%, Mn content 0.1% - 0.3%, Cu content 0.4% - 0.8%, La content 0.05% - 0.20%, Sn content 0.05% - 0.20%, Zr content 0.05% - 0.20%, the content range of Mn + La + Zr is 0.3% - 0.5%, and the balance is Al, by weight percentage.

[0008] 2) Homogenization treatment: A three-stage homogenization treatment process is adopted. The temperature of the first-stage homogenization is 420°C - 460°C, and the time of the first-stage homogenization is 8h - 16h; the temperature of the second-stage homogenization is 500°C - 540°C, and the time of the second-stage homogenization is 4h - 12h; the temperature of the third-stage homogenization is 550°C - 570°C, and the time of the third-stage homogenization is 2h - 6h.

[0009] 3) Extrusion molding: The homogenized aluminum rod is extruded into an aluminum alloy profile with the required cross-section. The extrusion outlet temperature is guaranteed to be above 530°C, and the online quenching cooling rate is greater than 400°C / min.

[0010] 4) Aging treatment: Multi-stage aging treatment is carried out on the extruded aluminum alloy profile to improve the strength. The temperature of the first-stage aging treatment is 80°C - 100°C, and the aging time is 4h - 8h; the temperature of the second-stage aging treatment is 120°C - 140°C, and the aging time is 10h - 20h; the temperature of the third-stage aging treatment is 160°C - 180°C, and the aging time is 2h - 6h.

[0011] In one embodiment, a method for preparing an ultra-high-strength aluminum alloy profile with low deformation resistance is as follows: 1) Preparation of aluminum rod: The alloy composition of the aluminum rod is as follows: the content of Mg is 2.2%, the content of Si is 1.0%, the content of Zn is 3.5%, the content of Fe is 0.19%, the content of Mn is 0.15%, the content of Cu is 0.5%, the content of La is 0.1%, the content of Sn is 0.1%, the content of Zr is 0.15%, the content range of Mn + La + Zr is 0.35%, and the balance is Al, by weight percentage; 2) Homogenization treatment: A three-stage homogenization treatment process is adopted. The temperature of the first-stage homogenization is 440°C, and the time of the first-stage homogenization is 12h; the temperature of the second-stage homogenization is 520°C, and the time of the second-stage homogenization is 8h; the temperature of the third-stage homogenization is 560°C, and the time of the third-stage homogenization is 4h; 3) Extrusion molding: The homogenized aluminum rod is extruded into an aluminum alloy profile with the required cross-section. The extrusion outlet temperature is guaranteed to be above 530°C, and the online quenching cooling rate is greater than 400°C / min; 4) Aging treatment: Multi-stage aging treatment is carried out on the extruded aluminum alloy profile to improve the strength. The temperature of the first-stage aging treatment is 95°C, and the aging time is 5h; the temperature of the second-stage aging treatment is 135°C, and the aging time is 12h; the temperature of the third-stage aging treatment is 175°C, and the aging time is 5h.

[0012] In one embodiment, a method for preparing an ultra-high strength aluminum alloy profile with low deformation resistance is as follows: 1) Prepare an aluminum rod. The alloy composition of the aluminum rod is as follows: Mg content is 2.5%, Si content is 1.2%, Zn content is 4.0%, Fe content is 0.17%, Mn content is 0.2%, Cu content is 0.6%, La content is 0.15%, Sn content is 0.15%, Zr content is 0.10%, the content range of Mn + La + Zr is 0.4%, and the balance is Al, by weight percentage; 2) Homogenization treatment. A three-stage homogenization treatment process is adopted. The first-stage homogenization temperature is 460 °C, and the first-stage homogenization time is 10 h; the second-stage homogenization temperature is 540 °C, and the second-stage homogenization time is 6 h; the third-stage homogenization temperature is 565 °C, and the third-stage homogenization time is 3 h; 3) Extrusion molding. The homogenized aluminum rod is extruded into an aluminum alloy profile with the required cross-section. The extrusion outlet temperature is ensured to be above 530 °C, and the online quenching cooling rate is greater than 400 °C / min; 4) Aging treatment. The extruded aluminum alloy profile is subjected to multi-stage aging treatment to improve the strength. The first-stage aging treatment temperature is 100 °C, and the aging time is 4 h; the second-stage aging treatment temperature is 140 °C, and the aging time is 10 h; the third-stage aging treatment temperature is 180 °C, and the aging time is 4 h.

[0013] In one embodiment, a method for preparing an ultra-high strength aluminum alloy profile with low deformation resistance is as follows: 1) Prepare an aluminum rod. The alloy composition of the aluminum rod is as follows: Mg content is 2.0%, Si content is 0.8%, Zn content is 3.0%, Fe content is 0.2%, Mn content is 0.1%, Cu content is 0.4%, La content is 0.08%, Sn content is 0.08%, Zr content is 0.20%, the content range of Mn + La + Zr is 0.36%, and the balance is Al, by weight percentage; 2) Homogenization treatment. A three-stage homogenization treatment process is adopted. The first-stage homogenization temperature is 420 °C, and the first-stage homogenization time is 14 h; the second-stage homogenization temperature is 500 °C, and the second-stage homogenization time is 10 h; the third-stage homogenization temperature is 555 °C, and the third-stage homogenization time is 5 h; 3) Extrusion molding. The homogenized aluminum rod is extruded into an aluminum alloy profile with the required cross-section. The extrusion outlet temperature is ensured to be above 530 °C, and the online quenching cooling rate is greater than 400 °C / min; 4) Aging treatment. The extruded aluminum alloy profile is subjected to multi-stage aging treatment to improve the strength. The first-stage aging treatment temperature is 85 °C, and the aging time is 7 h; the second-stage aging treatment temperature is 125 °C, and the aging time is 20 h; the third-stage aging treatment temperature is 165 °C, and the aging time is 6 h.

[0014] In one embodiment, a method for preparing an ultra-high strength aluminum alloy profile with low deformation resistance is as follows: 1) Prepare an aluminum rod. The alloy composition of the aluminum rod is: 2.8% Mg, 1.4% Si, 4.5% Zn, 0.18% Fe, 0.25% Mn, 0.7% Cu, 0.18% La, 0.18% Sn, 0.12% Zr, and the content range of Mn + La + Zr is 0.48%, with the balance being Al, by weight percentage; 2) Homogenization treatment. A three-stage homogenization treatment process is adopted. The first-stage homogenization temperature is 450°C and the first-stage homogenization time is 11 h; the second-stage homogenization temperature is 530°C and the second-stage homogenization time is 7 h; the third-stage homogenization temperature is 565°C and the third-stage homogenization time is 3 h; 3) Extrusion forming. The homogenized aluminum rod is extruded into an aluminum alloy profile with the required cross-section. The extrusion outlet temperature is ensured to be above 530°C, and the online quenching cooling rate is greater than 400°C / min; 4) Aging treatment. Multistage aging treatment is carried out on the extruded aluminum alloy profile to improve the strength. The first-stage aging treatment temperature is 90°C and the aging time is 6 h; the second-stage aging treatment temperature is 130°C and the aging time is 15 h; the third-stage aging treatment temperature is 170°C and the aging time is 6 h.

[0015] On the other hand, the present invention also provides an ultra-high strength aluminum alloy profile with low deformation resistance, which is prepared by using the method for preparing an ultra-high strength aluminum alloy profile with low deformation resistance as described above.

[0016] On the other hand, the present invention also provides the application of the ultra-high strength aluminum alloy profile with low deformation resistance as described above in automotive profiles with a multi-cavity structure.

[0017] On the other hand, the present invention also provides the application of the ultra-high strength aluminum alloy profile with low deformation resistance as described above in automotive battery trays or automotive sill beams.

[0018] The present invention proposes a new type of ultra-high strength aluminum alloy profile with low deformation resistance. Through the double strengthening of ZnMgCu and MgSi, the mechanical properties of the material can be greatly improved, breaking through the limitation of only using a single component strengthening phase in traditional 6-series and 7-series alloys. At the same time, the unique aging treatment process avoids the decrease in corrosion resistance caused by high Zn and reduces the increase in deformation resistance caused by the solid solution of Mg and Cu elements inside the alloy during high-temperature extrusion, greatly improving the extrudability of the material.

[0019] Compared with the prior art, the present invention has at least the following beneficial effects.

[0020] 1. The present invention breaks through the limitation of using only a single-component strengthening phase in traditional 6xxx and 7xxx alloys through the double overlapping strengthening phases of ZnMgCu and MgSi, greatly improving the mechanical properties of the material and achieving ultra-high strength.

[0021] 2. The present invention adopts a unique multi-stage aging treatment process to avoid the decline in corrosion resistance caused by a high Zn content, ensuring good corrosion resistance of the material.

[0022] 3. The present invention reduces the effect of the increase in deformation resistance caused by the solid solution of Mg and Cu elements inside the alloy during hot extrusion, greatly improving the extrudability of the material. Among alloys with the same strength, the deformation resistance at 500 °C is reduced by about 20%, and the extrusion efficiency can be increased by more than 30%, achieving low deformation resistance.

[0023] 4. The novel aluminum alloy prepared by the present invention simultaneously achieves the goals of ultra-high strength, good corrosion resistance, and low deformation resistance, and is very suitable for producing ultra-high strength profile automotive parts with complex cross-sections.

[0024] Some other beneficial effects of the present invention will become more obvious in the following description or be understood in practice. Detailed Embodiments

[0025] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0026] A method for preparing an ultra-high strength aluminum alloy profile with low to medium deformation resistance, the preparation steps are as follows:

[0027] 1. Prepare an aluminum rod, and the alloy composition of the aluminum rod is: Mg content 2.0% - 3.0%, Si content 0.8% - 1.4%, Zn content 3.0 - 4.5%, Fe content less than 0.3%, Mn content 0.1% - 0.3%, Cu content 0.4% - 0.8%, La content 0.05% - 0.20%, Sn content 0.05% - 0.20%, Zr content 0.05% - 0.20%, the content range of Mn + La + Zr is 0.3% - 0.5%, and the balance is Al.

[0028] In the alloy composition, elements such as Zn, Mg, Si, and Cu are mainly used to form ZnMgCu and MgSi strengthening phases during the solution aging process to significantly improve the material strength; Fe and Mn elements are mainly used to control the structure of the Fe phase formation while avoiding excessive consumption of Si by Fe to reduce the material strength; La is mainly used to purify impurity elements, improve the material plasticity, and reduce the deformation resistance; Sn is mainly used to avoid excessive precipitation of Mg elements in the first-stage low-temperature stage during the multi-stage aging process, which may lead to insufficient Mg and Si to form MgSi precipitation phases in the subsequent high-temperature aging stage.

[0029] II. Homogenization treatment: A three-stage homogenization treatment process is adopted. The first-stage homogenization temperature is 420°C - 460°C, and the first-stage homogenization time is 8h - 16h; the second-stage homogenization temperature is 500°C - 540°C, and the second-stage homogenization time is 4h - 12h; the third-stage homogenization temperature is 550°C - 570°C, and the third-stage homogenization time is 2h - 6h.

[0030] The purpose of the third-stage homogenization is to ensure that most of the Mg and all of the Zn and Cu elements complete solid solution through the first-stage homogenization treatment. The second-stage homogenization is to fully dissolve the eutectic phase to avoid the eutectic overburn defect caused by direct high temperature. Then, through the third-stage homogenization treatment, all of the Mg and Si elements complete solid solution, and it promotes the transformation and uniform distribution of the Fe phase.

[0031] III. Extrusion forming: The homogenized aluminum rod is extruded into an aluminum alloy profile with the required cross-section. Online solution is carried out during the extrusion process, and the extrusion exit temperature is ensured to be above 530°C, and the online quenching cooling rate is greater than 400°C / min.

[0032] IV. Aging treatment: The extruded aluminum alloy profile is subjected to multi-stage aging treatment to improve the strength. The first-stage aging treatment temperature is 80°C - 100°C, and the aging time is 4h - 8h; the second-stage aging treatment temperature is 120°C - 140°C, and the aging time is 10h - 20h; the third-stage aging treatment temperature is 160°C - 180°C, and the aging time is 2h - 6h.

[0033] The purpose of the multi-stage aging treatment is to first promote the precipitation of internal ZnMgCu strengthening phases and MgSi pre-β" phases through the low-temperature first and second-stage aging, and then promote the coarsening and disconnection of ZnMg strengthening phases at the grain boundaries through the third-stage aging to improve the corrosion resistance of the material, and promote the transformation of MgSi pre-β" phases to β" phases, simultaneously increasing the strengthening effect of MgSi strengthening phases.

[0034] To better demonstrate the progressiveness of the present invention, different examples and comparative examples are formed by adjusting the alloy composition and process parameters of the aluminum alloy profile. The comparison of the alloy composition and process parameters of each example and comparative example is shown in Table 1 and Table 2. The process parameter differences not shown in Table 2 are defaulted to be the same.

[0035] Table 1. Comparison of Alloy Composition of Examples 1-4 and Comparative Examples 1-6 Type Magnesium Silicon Zinc Iron Manganese Copper Lanthanum Tin Zirconium Manganese + Lanthanum + Zirconium Example 1 2.2 1 3.5 0.19 0.15 0.5 0.1 0.1 0.15 0.35 Example 2 2.5 1.2 4 0.17 0.2 0.6 0.15 0.15 0.1 0.4 Example 3 2 0.8 3 0.2 0.1 0.4 0.08 0.08 0.2 0.36 Example 4 2.8 1.4 4.5 0.18 0.25 0.7 0.18 0.18 0.12 0.48 Comparative Example 1 2.5 1.2 4 0.17 0.2 0.6 0.15 0.15 0.1 0.4 Comparative Example 2 2.5 1.2 4 0.17 0.2 0.6 0.15 0.15 0.1 0.4 Comparative Example 3 2.5 1.2 4 0.17 0.2 0.6 0.15 0.15 0.1 0.4 Comparative Example 4 2.5 1.2 4 0.17 0.2 0.6 0.15 0.15 0.1 0.4 Comparative Example 5 2.3 0.05 3.8 0.17 0.18 0.55 0.14 0.13 0.08 0.35 Comparative Example 6 2.7 1 4.2 0.17 0.22 0.65 0 0 0 0

[0036] Table 2. Comparison of Process Parameters of Examples 1-4 and Comparative Examples 1-6 。

[0037] The product performance of the aluminum alloy profiles prepared in each example and comparative example is shown in Table 3.

[0038] Table 3. Comparison of Product Performance of Examples 1-4 and Comparative Examples 1-6 Type Tensile strength (MPa) Yield strength (MPa) Elongation rate (%) Intergranular corrosion grade Example 1 475 440 10.5 3 Example 2 490 455 9.8 3 Example 3 468 432 11.2 3 Example 4 482 448 10.2 3 Comparative Example 1 450 410 10 3 Comparative Example 2 440 390 11 2 Comparative Example 3 445 400 10.5 3 Comparative Example 4 455 415 9.5 4 Comparative Example 5 410 375 11.5 3 Comparative Example 6 460 420 7.5 4

[0039] It can be seen from Table 1 to Table 3 that when the parameters of the homogenization treatment process or the aging treatment process change, the tensile strength and yield strength of the product both decrease significantly; when the silicon content is lower than the lower limit, the tensile strength and yield strength of the product both decrease significantly; when the contents of lanthanum, tin and zirconium are lower than the lower limit, the tensile strength, yield strength and elongation of the product all decrease significantly.

[0040] In the present invention, the decrease in the deformation resistance is shown in Table 4.

[0041] Table 4. Extrusion Deformation Resistance in Examples 1-4 Type Maximum breakthrough pressure Mpa Average extrusion speed m / min Yield strength Mpa after aging Example 1 275 3.1 440 Example 2 283 2.8 455 Example 3 273 3.1 432 Example 4 278 2.9 448 7003 alloy 285 3.3 324 7022 alloy 297 2.1 437 7075 alloy 300 1.1 509

[0042] It can be seen from Table 4 that in alloys of the same strength, the deformation resistance at 500 °C is reduced by more than 20%, and the extrusion efficiency can be increased by more than 30%.

[0043] It should be noted that the technical features of the above examples can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above examples are described. However, as long as the combinations of these technical features do not conflict, they should all be considered as within the scope described in this specification.

[0044] The above embodiments only illustrate several implementation manners of the present invention. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can be made, and these all belong to the protection scope of the present invention. The parts not described in the specific embodiments are all prior art or common general knowledge.

[0045] In addition, it should be noted that in the description of the present invention, the detailed description of the preferred implementation methods of the present invention and the included embodiments can more easily understand the content of the present invention. Unless otherwise defined, all the technologies and scientific terms used in the present invention have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. When there is a contradiction, the definition in this specification shall prevail.

[0046] In the present invention, the term "prepared from" is synonymous with "comprising". The terms "comprising", "including", "having", "containing" or any other variation thereof used in the present invention are intended to cover non-exclusive inclusion. For example, a composition, step, method, article or device comprising the listed elements is not necessarily limited to those elements, but may include other elements not expressly listed or elements inherent to such composition, step, method, article or device.

[0047] In the present invention, when an equivalent, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper preferred values and lower preferred values, it should be understood that all ranges formed by any pairing of any range upper limit or preferred value with any range lower limit or preferred value are specifically disclosed, regardless of whether the ranges are separately disclosed. For example, when the range "1 to 5" is disclosed, the described range should be interpreted as including the ranges "1 to 4", "1 to 3", "1 to 2", "1 to 2 and 4 to 5", "1 to 3 and 5", etc. When a numerical range is described in the present invention, unless otherwise specified, the range is intended to include its end values and all integers and fractions within the range.

[0048] Furthermore, the indefinite articles "a" and "an" before the elements or components of the present invention do not limit the quantity requirement (i.e., the number of occurrences) of the elements or components. Therefore, "a" or "an" should be interpreted as including one or at least one, and the singular form of the elements or components also includes the plural form, unless the quantity clearly refers to the singular form.

Claims

1. A method for preparing an ultra-high strength medium-low deformation resistance aluminum alloy profile, characterized in that: The preparation steps are as follows: 1) Prepare an aluminum rod, the alloy composition of the aluminum rod is: Mg content 2.0%-3.0%, Si content 0.8%-1.4%, Zn content 3.0-4.5%, Fe content less than 0.3%, Mn content 0.1%-0.3%, Cu content 0.4%-0.8%, La content 0.05%-0.20%, Sn content 0.05%-0.20%, Zr content 0.05%-0.20%, Mn+La+Zr content range 0.3%-0.5%, and the balance is Al, calculated by weight percentage; 2) Homogenization treatment, adopting a three-stage homogenization process, the first-stage homogenization temperature is 420℃-460℃, the first-stage homogenization time is 8h-16h; the second-stage homogenization temperature is 500℃-540℃, the second-stage homogenization time is 4h-12h; the third-stage homogenization temperature is 550℃-570℃, and the third-stage homogenization time is 2h-6h; 3) Extrusion molding: the homogenized aluminum rod is extruded to obtain the aluminum alloy profile with the required cross section. The extrusion outlet temperature is guaranteed to be above 530℃, and the online quenching cooling rate is greater than 400℃ / min; 4) Aging treatment: The extruded aluminum alloy profiles are subjected to multi-stage aging treatment to improve their strength. The first-stage aging treatment temperature is 80℃-100℃, and the aging time is 4h-8h; the second-stage aging treatment temperature is 120℃-140℃, and the aging time is 10h-20h; the third-stage aging treatment temperature is 160℃-180℃, and the aging time is 2h-6h.

2. The method for preparing an ultra-high strength medium-low deformation resistance aluminum alloy profile according to claim 1, characterized in that: The preparation steps are as follows: 1) Prepare an aluminum rod, the alloy composition of the aluminum rod is: Mg content 2.2%, Si content 1.0%, Zn content 3.5%, Fe content 0.19%, Mn content 0.15%, Cu content 0.5%, La content 0.1%, Sn content 0.1%, Zr content 0.15%, Mn+La+Zr content range 0.35%, and the balance is Al, calculated by weight percentage; 2) Homogenization treatment: a three-stage homogenization treatment process is adopted, the first-stage homogenization temperature is 440°C, the first-stage homogenization time is 12h; the second-stage homogenization temperature is 520°C, the second-stage homogenization time is 8h; the third-stage homogenization temperature is 560°C, and the third-stage homogenization time is 4h; 3) Extrusion molding: the homogenized aluminum rod is extruded to obtain the aluminum alloy profile with the required cross section. The extrusion outlet temperature is guaranteed to be above 530℃, and the online quenching cooling rate is greater than 400℃ / min; 4) Aging treatment: The extruded aluminum alloy profiles are subjected to multi-stage aging treatment to improve their strength. The first-stage aging treatment temperature is 95°C and the aging time is 5h; the second-stage aging treatment temperature is 135°C and the aging time is 12h; the third-stage aging treatment temperature is 175°C and the aging time is 5h.

3. The method for preparing an ultra-high strength medium-low deformation resistance aluminum alloy profile according to claim 1, characterized in that: The preparation steps are as follows: 1) Prepare an aluminum rod, the alloy composition of the aluminum rod is: Mg content 2.5%, Si content 1.2%, Zn content 4.0%, Fe content 0.17%, Mn content 0.2%, Cu content 0.6%, La content 0.15%, Sn content 0.15%, Zr content 0.10%, Mn+La+Zr content range 0.4%, and the balance is Al, calculated by weight percentage; 2) Homogenization treatment: a three-stage homogenization process is adopted, with the first-stage homogenization temperature being 460°C and the first-stage homogenization time being 10 hours; the second-stage homogenization temperature being 540°C and the second-stage homogenization time being 6 hours; the third-stage homogenization temperature being 565°C and the third-stage homogenization time being 3 hours; 3) Extrusion molding: the homogenized aluminum rod is extruded to obtain the aluminum alloy profile with the required cross section. The extrusion outlet temperature is guaranteed to be above 530℃, and the online quenching cooling rate is greater than 400℃ / min; 4) Aging treatment: The extruded aluminum alloy profiles are subjected to multi-stage aging treatment to improve their strength. The first-stage aging treatment temperature is 100°C and the aging time is 4h; the second-stage aging treatment temperature is 140°C and the aging time is 10h; the third-stage aging treatment temperature is 180°C and the aging time is 4h.

4. The method for preparing an ultra-high strength medium-low deformation resistance aluminum alloy profile according to claim 1, characterized in that: The preparation steps are as follows: 1) Prepare an aluminum rod, the alloy composition of the aluminum rod is: Mg content 2.0%, Si content 0.8%, Zn content 3.0%, Fe content 0.2%, Mn content 0.1%, Cu content 0.4%-, La content 0.08%, Sn content 0.08%, Zr content 0.20%, Mn+La+Zr content range 0.36%, and the balance is Al, calculated by weight percentage; 2) Homogenization treatment: a three-stage homogenization treatment process is adopted, with the first-stage homogenization temperature being 420°C and the first-stage homogenization time being 14 hours; the second-stage homogenization temperature being 500°C and the second-stage homogenization time being 10 hours; the third-stage homogenization temperature being 555°C and the third-stage homogenization time being 5 hours; 3) Extrusion molding: the homogenized aluminum rod is extruded to obtain the aluminum alloy profile with the required cross section. The extrusion outlet temperature is guaranteed to be above 530℃, and the online quenching cooling rate is greater than 400℃ / min; 4) Aging treatment: The extruded aluminum alloy profiles are subjected to multi-stage aging treatment to improve their strength. The first-stage aging treatment temperature is 85°C and the aging time is 7h; the second-stage aging treatment temperature is 125°C and the aging time is 20h; the third-stage aging treatment temperature is 165°C and the aging time is 6h.

5. The method for preparing an ultra-high strength medium-low deformation resistance aluminum alloy profile according to claim 1, characterized in that: The preparation steps are as follows: 1) preparing an aluminum rod, the alloy composition of the aluminum rod is: Mg content 2.8%, Si content 1.4%, Zn content 4.5%, Fe content 0.18%, Mn content 0.25%, Cu content 0.7%, La content 0.18%, Sn content 0.18%, Zr content 0.12%, Mn+La+Zr content range 0.48%, and the balance is Al, calculated by weight percentage; 2) Homogenization treatment: a three-stage homogenization process is adopted, with the first-stage homogenization temperature being 450°C and the first-stage homogenization time being 11 hours; the second-stage homogenization temperature being 530°C and the second-stage homogenization time being 7 hours; the third-stage homogenization temperature being 565°C and the third-stage homogenization time being 3 hours; 3) Extrusion molding: the homogenized aluminum rod is extruded to obtain the aluminum alloy profile with the required cross section. The extrusion outlet temperature is guaranteed to be above 530℃, and the online quenching cooling rate is greater than 400℃ / min; 4) Aging treatment: The extruded aluminum alloy profiles are subjected to multi-stage aging treatment to improve their strength. The first-stage aging treatment temperature is 90°C and the aging time is 6h; the second-stage aging treatment temperature is 130°C and the aging time is 15h; the third-stage aging treatment temperature is 170°C and the aging time is 6h.

6. An ultra-high strength low deformation resistance aluminum alloy profile, characterized in that: The aluminum alloy profile is prepared by the method for preparing an ultra-high strength medium-low deformation resistance aluminum alloy profile as described in any one of claims 1 to 5.

7. Application of the ultra-high strength and medium-low deformation resistance aluminum alloy profile as claimed in claim 6 to automobile profiles with a multi-cavity structure.

8. Application of the ultra-high strength, medium-low deformation resistance aluminum alloy profile as claimed in claim 6 to an automobile battery tray or an automobile door sill beam.