A lightweight high-strength high-toughness high-magnesium-content Al-Mg-Zn aluminum alloy and a preparation method thereof

Abstract

The application discloses a kind of light high-strength high-toughness high-magnesium content Al-Mg-Zn aluminum alloy and preparation method thereof.The alloy contains Al 84.84~90.88wt%,Mg 6.01~9.95wt%,Zn 3.01~3.99wt%,Si 0.025~0.099wt%,and total content is not more than 0.75wt% of at least one of Mn,Cu,Zr,Sc,Ti,Be,Sb element;Mg,Zn and Si content satisfy the relationship formula:2.80≤[(5×Mg)+Zn] / [(2×Si)+(3×Zn)]≤5.78.The preparation method includes the following steps: (1) manufacturing aluminum alloy ingot;(2) the obtained ingot is uniformly treated and / or preheated;(3) the ingot is hot worked into the required processing material form or pre-processing material by hot deformation processing method;(4) optionally, the pre-processing material is reheated, and the required processing material form is processed by cold deformation;(5) the processing material is solid solution heat treated;(6) the processing material after solid solution heat treatment is rapidly cooled to room temperature;(7) the processing material is aged to obtain alloy aged processing material.The aluminum alloy material shows low density, high strength and fracture toughness.

Description

[0001] This application is a divisional application of the invention patent application with application number 2026102270633, application date February 26, 2026, entitled "A lightweight, high-strength, high-toughness, high-magnesium-content Al-Mg-Zn aluminum alloy and its preparation method". Technical Field

[0002] This invention belongs to the field of aluminum alloys and their preparation and processing technology, and particularly relates to Al-Mg-Zn series aluminum alloys. More specifically, this invention relates to a lightweight, high-strength, high-toughness, high-magnesium-content Al-Mg-Zn series aluminum alloy and its preparation method. Background Technology

[0003] Aluminum alloys possess advantages such as light weight, high specific strength, ease of processing, and low cost, making them widely used in aerospace, transportation, and weaponry. In recent years, with the increasing demand for lightweight structures in aviation, aerospace, and marine equipment, it is necessary to develop new aluminum alloy materials with comprehensive properties such as low density, ultra-high strength, high fracture toughness, and good strength-toughness matching to better support the weight reduction design of aluminum alloy structural components, in order to meet the requirements of high load-bearing capacity, long service life, and service in extreme environments. Previous studies have found that adding Zn to Al-Mg alloys achieves good strength and toughness while also resulting in significant weight reduction. In recent years, a series of studies have been conducted on high-magnesium-content Al-Mg-Zn aluminum alloys, and related results have emerged.

[0004] Patent document CN116065066A discloses a lightweight, high-strength, and corrosion-resistant aluminum alloy material. The addition of 0.1–1.3 wt% Si element results in the precipitation of a Mg2Si precipitate strengthening phase during aging and reduces the precipitation of the β-Al3Mg2 phase, enabling the alloy to achieve good strength and toughness while maintaining certain corrosion resistance. Furthermore, other studies have also conducted multi-element synergistic optimization of Al-Mg-Zn alloys. For example, patent document CN120158653A proposes an Al-Mg-Zn-Cu-Sc-Zr alloy containing Cu, Sc, and Zr, emphasizing the synergy between weldability and corrosion resistance; patent document CN121109827A introduces Sb element to improve the hot-processing plasticity of high-magnesium alloys; and patent document CN119876704A focuses on marine corrosion resistance by controlling the proportions of Cu, Mn, Sc, and Er to enhance corrosion resistance. However, although the above studies have different focuses on strength, corrosion resistance or processability, in the pursuit of higher strength levels, it is often difficult to achieve both high fracture toughness and a good strength-toughness match. In particular, the fracture toughness is often insufficient under high strength conditions, which limits its application.

[0005] Therefore, based on the previous CN116065066A alloy system, further optimization of the alloy composition design, especially by appropriately increasing the Zn content, optimizing the Mg content range, and precisely controlling the Si element content and the ratio of Mg and Zn elements, is expected to further improve the alloy strength and significantly enhance fracture toughness while maintaining low density, achieving comprehensive performance of ultra-high strength, high toughness, and good strength-toughness matching, and meeting the higher requirements of high-end equipment for aluminum alloy materials. Summary of the Invention

[0006] Based on extensive research and industrial practice in patent document CN116065066A, this invention conducts composition optimization and time-aging precipitation behavior studies. Through numerous laboratory studies and industrial verifications, it was discovered that by optimizing the alloy composition, a lightweight, high-strength, high-toughness, and high-magnesium-content Al-Mg-Zn alloy with higher strength and fracture toughness, and a better strength-toughness match, can be obtained. Adding Si as a trace element to this alloy and precisely controlling its content can significantly promote T-Mg precipitation in the matrix. 32 (Al,Zn) 49 Phase nucleation and increasing the number of matrix precipitates during aging can improve the strength of the alloy by maintaining the fine size of the precipitates and achieving a dense distribution. Furthermore, by controlling the Mg and Zn content and their ratio, T-Mg near the grain boundaries can be achieved. 32 (Al,Zn) 49 The precipitation and transformation of the phase and η-MgZn2 phase effectively fill the "grain boundary precipitation-free zone" that is common in traditional alloys, significantly improving the fracture toughness of the alloy and achieving a good strength-toughness match.

[0007] The purpose of this invention is to further improve the strength, fracture toughness, and strength-toughness matching level of the alloy by optimizing the composition design of the existing lightweight, high-strength, and corrosion-resistant aluminum alloy (patent document CN116065066A), and to provide a lightweight, high-strength, and high-fracture-toughness aluminum alloy.

[0008] This invention relates to a lightweight, high-strength, high-toughness, and high-magnesium-content Al-Mg-Zn aluminum alloy, wherein the aluminum alloy contains: Al 84.84~90.88wt%, Mg 6.01~9.95wt%, Zn 3.01~3.99wt%, Si 0.025~0.099wt%, and at least one of Mn, Cu, Zr, Sc, Ti, Be, and Sb with a total content not exceeding 0.75wt%; the contents of Mg, Zn, and Si satisfy the following relationship: 2.80≤[(5×Mg)+Zn] / [(2×Si)+(3×Zn)]≤5.78.

[0009] The alloy of the present invention may also contain other elements that have the same refining and modifying effects as Mn, Cu, Zr, Sc, Ti, Be, Sb, etc.

[0010] The first preferred embodiment of the present invention is that the aluminum alloy contains: Al 85.65~89.88wt%, Mg 7.01~9.19wt%, Zn 3.01~3.99wt%, Si 0.025~0.099wt%, and at least one of Mn, Cu, Zr, Sc, Ti, Be, and Sb in a total content not exceeding 0.7wt%.

[0011] As a second preferred embodiment of the present invention, the aluminum alloy contains: Al 85.65~89.38wt%, Mg 7.01~9.19wt%, Zn 3.51~3.99wt%, Si 0.025~0.099wt%, and at least one of Mn, Cu, Zr, Sc, Ti, Be, and Sb in a total content not exceeding 0.7wt%.

[0012] As a third preferred embodiment of the present invention, the contents of Mg, Zn and Si in the aluminum alloy satisfy the following relationship: 3.21≤[(5×Mg)+Zn] / [(2×Si)+(3×Zn)]≤5.39.

[0013] As a fourth preferred embodiment of the present invention, the contents of Mg, Zn and Si in the aluminum alloy satisfy the following relationship: 3.21≤[(5×Mg)+Zn] / [(2×Si)+(3×Zn)]≤4.67.

[0014] As a fifth preferred embodiment of the present invention, the aluminum alloy contains: Mn 0.03~0.45wt%.

[0015] As a sixth preferred embodiment of the present invention, the aluminum alloy contains: Cu 0.02~0.60wt%.

[0016] As a seventh preferred embodiment of the present invention, the aluminum alloy contains: Zr 0.05~0.25wt%.

[0017] As an eighth preferred embodiment of the present invention, the aluminum alloy contains: 0.02~0.25wt% Sc; preferably, it also contains 0.05~0.25wt% Zr; more preferably, the content of Sc and Zr satisfies: 0.12wt% ≤ (Sc+Zr)wt% ≤ 0.30wt%.

[0018] As a ninth preferred embodiment of the present invention, the aluminum alloy contains: Ti 0.001~0.11wt%; preferably, it also contains Zr 0.05~0.25wt%; more preferably, the content of Ti and Zr satisfies: 0.10wt%≤(Ti+Zr)wt%≤0.30wt%.

[0019] As a tenth preferred embodiment of the present invention, the aluminum alloy contains: Be 0.0002~0.025wt%.

[0020] As the eleventh preferred embodiment of the present invention, the aluminum alloy contains: Sb 0.005~0.025wt%.

[0021] As a twelfth preferred embodiment of the present invention, the aluminum alloy contains elements unintentionally introduced as impurities during the manufacturing process of the alloy ingot, which must satisfy Fe ≤ 0.30 wt%, each of the other impurity elements ≤ 0.20 wt%, and the total ≤ 0.45 wt%; preferably, Fe ≤ 0.20 wt%, each of the other impurity elements ≤ 0.10 wt%, and the total ≤ 0.28 wt%; more preferably, Fe ≤ 0.18 wt%.

[0022] This invention also relates to a method for producing the aforementioned aluminum alloy. The process for producing the wrought aluminum alloy can be described as follows: "Alloy preparation and smelting – semi-continuous casting to prepare ingots – homogenization heat treatment of the ingots – hot deformation processing – (intermediate annealing) – (cold deformation processing) – solution treatment – ​​(pre-deformation or straightening) – aging treatment – ​​product supply"; the basic preparation process for the aluminum alloy casting can be described as follows: "Alloy preparation and smelting – casting – solution treatment – ​​aging treatment – ​​product supply". The method for producing this wrought aluminum alloy material includes the following steps: (1) Manufacturing a semi-continuous casting ingot as described in this invention; (2) The resulting ingot is subjected to homogenization heat treatment and / or preheating; (3) The ingot is hot-deformed into the required form of the material by one or more hot deformation processing methods selected from extrusion, rolling and forging, or hot-deformed into a pre-processed material; (4) Optionally, the pre-processed material can be reheated and then cold-deformed into the required material form; (5) Perform solution heat treatment on the processed material; (6) Rapidly cool the solution-treated material to room temperature; and (7) The cooled processed material is subjected to natural aging or artificial aging treatment to obtain alloy aged processed material.

[0023] In step (1), the ingot is manufactured using smelting, degassing, inclusion removal, and semi-continuous casting. During smelting, Mg and Zn are used as the core elements to precisely control the content of the elements. Through online composition analysis, the ratio between alloying elements is quickly adjusted to complete the entire ingot manufacturing process. In one preferred aspect, 0.001~0.11wt% Ti is added in the form of an Al-Ti master alloy during smelting to refine the grains. In another preferred aspect, 0.0002~0.025wt% Be is added in the form of an Al-Be master alloy during smelting to change the oxide film properties and reduce oxidation loss and inclusions. In a third preferred aspect, 0.005~0.025% Sb is added in the form of an Al-Sb master alloy to neutralize alkali metal impurities such as Na in the alloy, improve the surface quality of the ingot, and enhance the hot working plasticity of the alloy. In another preferred aspect, step (1) further includes applying an electromagnetic field, an ultrasonic field, or mechanical stirring at or near the crystallizer.

[0024] In step (2), the homogenization heat treatment is performed by means of the group selected from: (1) a single-stage homogenization heat treatment for a total time of 10 to 80 h in the range of 390 to 480 °C; and (2) a two-stage or multi-stage homogenization heat treatment for a total time of 10 to 60 h in the range of 390 to 500 °C.

[0025] In steps (3) and (4), the preheating temperature and reheating temperature before each hot deformation process are 350~430℃, and the processing time is 1~5h; in a preferred aspect, an intermediate annealing process of 350~420℃ / 0.5~8h is added between cold deformation passes.

[0026] In step (5), the solution heat treatment needs to further adjust the subgrain size, recrystallization size, and ratio in the material according to performance requirements, and is carried out by means selected from the group consisting of: (1) single-stage, double-stage, or multi-stage solution heat treatment with a total time of 0.5 to 8 hours in the range of 420 to 500 °C; and (2) continuous heating solution heat treatment with a total time of 0.5 to 6 hours in the range of 420 to 500 °C. In a preferred aspect, the continuous heating solution heat treatment is used, and the heating rate is ≤60 °C / min.

[0027] In step (6), the workpiece is rapidly cooled to room temperature using a method selected from cooling medium spray quenching, immersion quenching, forced air cooling, and combinations thereof.

[0028] In step (7), the artificial aging heat treatment is carried out by means of the following group: (1) natural aging at room temperature after quenching and cooling for ≥24h; (2) artificial aging treatment within 2h after quenching and cooling in the range of 80~180℃ for a total time of 4~50h; and (3) after quenching and cooling, a combination of natural aging and artificial aging is used, with artificial aging temperature of 80~180℃ and time of 4~60h.

[0029] Between steps (6) and (7), the following steps may also be included: straightening and / or pre-deformation of the cooled processed material, using roller straightening, tension straightening, tension bending straightening and combinations thereof to improve the flatness of the processed material, and using tension, compression and combinations thereof to pre-deform to reduce the residual stress formed by quenching and cooling, so as to facilitate subsequent processing and application.

[0030] The processing material described in the preparation method of this invention is an extruded material, a sheet material, or a forging product.

[0031] The lightweight, high-strength, high-toughness, and high-magnesium-content Al-Mg-Zn alloy of this invention has a density ≤ 2.70 g / cm³. 3 Tensile strength ≥ 450 MPa, fracture toughness ≥ 32.0 MPa·m 1 / 2 Preferably, the density of the aluminum alloy is ≤2.69 g / cm³. 3 Tensile strength ≥ 470 MPa, fracture toughness ≥ 34.0 MPa·m 1 / 2 Further preferably, the density of the aluminum alloy is ≤2.68 g / cm³. 3 Tensile strength ≥ 490 MPa, fracture toughness ≥ 36.0 MPa·m 1 / 2 .

[0032] This invention also relates to a method for preparing the aluminum alloy casting, comprising the following steps: (1) Aluminum alloy castings are prepared by smelting, degassing, removing inclusions and sand casting, metal casting, or die casting. During the smelting process, the content of elements is precisely controlled with Mg and Zn as the core. The ratio between alloy elements is quickly adjusted by online composition detection and analysis, and the entire casting preparation process is completed. (2) Solution heat treatment of the obtained aluminum alloy castings: including single-stage, double-stage or multi-stage solution heat treatment of aluminum alloy castings in the range of 420~500℃ for a total time of 0.5~8h, or continuous heating solution heat treatment of aluminum alloy castings in the range of 420~500℃ for a total time of 0.5~6h. (3) Perform natural aging or artificial aging heat treatment on aluminum alloy castings; natural aging is carried out at room temperature for ≥24h; artificial aging is carried out in the range of 80~180℃ for a total time of 4~50h; or a combination of natural aging and artificial aging is used, with artificial aging temperature of 80~180℃ and time of 4~50h.

[0033] As described in this invention, the aluminum alloy can be welded together with itself or other alloys to form new products; the welding methods include friction stir welding, fusion welding, brazing, electron beam welding, and laser welding. It can also be processed into final components through various surface treatments, stamping, and machining; the final components are load-bearing structural parts.

[0034] The beneficial effects of this invention are as follows: (1) By precisely controlling the content of microalloyed Si, the T-Mg content in the matrix was significantly promoted. 32 (Al,Zn) 49 nucleation of the phase, T-Mg after aging 32 (Al,Zn) 49 The number of phases increased significantly, and they achieved a dense distribution while maintaining a small size, thus improving the strength of the alloy. Compositional optimization design was carried out on Al-Mg-Zn-Si aluminum alloys. By controlling the Mg and Zn content and their ratio, T-Mg near the grain boundaries was achieved. 32 (Al,Zn) 49 The precipitation and transformation of the η-MgZn2 phase effectively fill the "grain boundary precipitation-free zone" commonly found in traditional alloys, significantly improving the fracture toughness of the alloy and achieving a good balance between strength and toughness. The material exhibits excellent comprehensive performance and can meet the stringent requirements of various high-end manufacturing industries for lightweight, high-performance aluminum alloy materials.

[0035] (2) This invention further explores the comprehensive performance potential of the alloy, requires a moderate price, does not contain expensive elements such as Ag and Li, and has a simple and practical preparation method with strong operability. It is easy to promote industrialization and is conducive to promoting the development of lightweighting in aerospace, transportation, automobile and shipbuilding fields. It has important social and economic benefits and has a promising market prospect. Attached Figure Description

[0036] Figure 1 This is a comparison of the specific strength and fracture toughness of the alloy of the present invention with those of typical existing alloys. Detailed Implementation

[0037] The present invention will be further described below with reference to the accompanying drawings and embodiments. It should be emphasized that the following description is merely exemplary and is not intended to limit the scope of the invention or its application.

[0038] Example 1 Alloy extruded sheets and strips were prepared on a laboratory scale to demonstrate the principles of the invention. The composition of the experimental alloys is shown in Table 1.

[0039] Φ210mm round ingots were prepared using well-known alloy smelting, degassing, inclusion removal, and simulated semi-continuous casting conditions. The homogenization heat treatment regime for the ingots was selected as (400±5℃ / 12h) + (465±5℃ / 24h), followed by air cooling. After peeling, milling, and sawing, Φ180mm extruded billets were obtained. The billets were preheated at 380±10℃ for 4h, and then extruded to obtain 16×62mm strips, with the extrusion temperature controlled at around 380℃. The extruded strips were placed in an air furnace at 450℃ and subjected to continuous solution heat treatment at 450~480℃ for a total time of 90min. After water quenching, they were immediately subjected to 2.0~3.0% tensile straightening treatment, followed by a two-stage aging treatment of 90±5℃ / 24h + 140±5℃ / 8~14h, depending on the alloy characteristics.

[0040] Samples were cut according to relevant methods, and the alloy was tested for density (GB / T 1423), tensile properties (GB / T 16865), and fracture toughness (GB / T 4161) according to relevant testing standards, which were used as common performance indicators of the alloy for evaluation. The results are shown in Table 2.

[0041] Table 1. Experimental alloy composition

[0042] Table 2 Performance test results of the experimental alloys

[0043] As can be seen from Table 2, alloys 1#, 2#, 3#, 4#, 5#, 6#, 7#, 8#, 9#, 10#, 11#, 12#, 13#, 14#, 15#, 16#, and 17# all exhibit a good balance of density, strength, plasticity, and fracture toughness: their density does not exceed 2.69 g / cm³. 3 The tensile strength remained above 530 MPa, the elongation after fracture was above 11.5%, and the fracture toughness was above 32.0 MPa·m. 1 / 2The properties of alloys 18#, 19#, 20#, 21#, 22#, and 23# did not meet the desired balance between density, strength, plasticity, and fracture toughness. Specifically, alloy 18# had excessively high Zn content, resulting in low fracture toughness and high density; alloy 19# had excessively high Mg content, leading to low elongation and fracture toughness; alloy 20# had excessively high Zn and Mg content, resulting in low elongation and fracture toughness; alloy 21# had excessively high Zn content, resulting in high density, low elongation, and low fracture toughness; alloy 22# had excessively high Si content, significantly reducing plasticity; and alloy 23# had excessively high Mg content and low Zn and Si content, resulting in low elongation and fracture toughness.

[0044] Example 2 Aluminum alloy rolled sheets were prepared in the laboratory, and the composition of the experimental alloy is shown in Table 3.

[0045] Flat ingots with a thickness of 100 mm were prepared using well-known alloy smelting, degassing, inclusion removal, and simulated semi-continuous casting conditions. All ingots underwent homogenization heat treatment at (400±5℃ / 12h) + (465±5℃ / 24h) followed by air cooling. After peeling, milling, and sawing, rolled billets with a thickness of 80 mm were obtained. The billets were preheated at 390±10℃ for 2 hours, with an initial rolling temperature of 380℃. Rolling was performed 2-3 times along the width of the ingot, followed by reversing the rolling direction and rolling along the length of the ingot to a thickness of approximately 25 mm. The plates were then placed in an air furnace at 450℃ for solution heat treatment at 450℃ / 90 min, followed by water quenching and immediately undergoing a 2.5% pre-stretch deformation treatment. Subsequently, based on the alloy characteristics, a two-stage aging treatment was performed at 90±5℃ / 24h + 140±5℃ / 10h.

[0046] Samples were cut according to relevant methods, and the alloy was tested for density (GB / T 1423), tensile properties (GB / T 16865), and fracture toughness (GB / T 4161) according to relevant testing standards, which were used as common performance indicators of the alloy for evaluation. The results are shown in Table 4.

[0047] Table 3 Experimental alloy composition

[0048] Note: * indicates that the element is an impurity element and is not added as an alloying element.

[0049] Table 4 Performance test results of the experimental alloys

[0050] As can be seen from Table 4, the 24# alloy of the present invention exhibits good strength and fracture toughness, which is significantly better than the 25# alloy without Si.

[0051] Example 3 Small-sized aluminum alloy forgings were prepared on a pilot-scale platform. The alloy composition is shown in Table 5.

[0052] Using well-known industry procedures such as alloy smelting, degassing, and inclusion removal, Ф505mm round ingots were prepared by semi-continuous casting. The homogenization heat treatment regime for the ingots was selected as (400±5℃ / 12h) + (465±5℃ / 24h), followed by air cooling. After peeling, milling, and sawing, a Ф482mm billet was obtained. The billet was preheated at 390±10℃ for 8h, and then forged in multiple directions to obtain small-sized forgings of 160×240×800mm, with the forging deformation temperature controlled at 390~410℃. The forgings were placed in an air furnace at 450℃ for solution heat treatment at 455℃ / 80min, followed by water quenching and immediately undergoing 2.0~2.5% pre-compression deformation treatment, and then a two-stage aging treatment of 90±5℃ / 24h + 140±5℃ / 6h.

[0053] Samples were cut according to relevant methods, and the alloy was tested for density (GB / T 1423), tensile properties (GB / T 16865), and fracture toughness (GB / T 4161) according to relevant testing standards, which were used as common performance indicators of the alloy for evaluation. The results are shown in Table 6.

[0054] Table 5 Experimental Alloy Composition

[0055] Table 6 Performance test results of the experimental alloys

[0056] As can be seen from Table 6, the 26# alloy of the present invention exhibits good strength and toughness.

[0057] Example 4 Aluminum alloy castings were prepared in the laboratory, and the alloy composition is shown in Table 7.

[0058] The process involves preparing raw materials (high-purity aluminum, pure magnesium, pure zinc, pure copper, Al-Mn master alloy, Al-Si master alloy, Al-Zr master alloy, Al-Sc master alloy, Al-Ti-B master alloy refiner), baking molds, melting high-purity aluminum at 730℃, and then adding pure zinc, pure copper, Al-Si, Al-Mn, Al-Sc, and Al-Zr master alloys in the conventional order, stirring until completely melted; cooling to 720℃ and adding Al-Ti-B master alloy, stirring and letting stand for 4-6 minutes; continuing to cool to 710℃ and then using a bell jar... Pure magnesium wrapped in aluminum foil is pressed into molten aluminum alloy and stirred to ensure complete melting. The mixture is then heated to 720℃ for degassing and slag removal refining, followed by pre-furnace inspection. After standing for 30 minutes at a casting temperature of 690℃, the molten aluminum alloy is poured into a preheated metal mold at a temperature of approximately 180-200℃. The resulting aluminum alloy casting is placed in an air furnace at 470℃ for solution heat treatment at 460±5℃ / 24h. After water cooling, it undergoes natural aging for 48h, followed by a two-stage aging treatment at 95±5℃ / 12h + 140±5℃ / 18h.

[0059] Samples were cut according to relevant methods, and the alloy was tested for density (GB / T 1423) and tensile properties (GB / T 16865) according to relevant testing standards to evaluate the alloy as commonly used performance indicators. The results are shown in Table 8.

[0060] Table 7 Experimental Alloy Composition

[0061] Table 8 Performance test results of the experimental alloys

[0062] As can be seen from Table 8, the 27# alloy of the present invention exhibits higher strength compared with the 28# alloy (Al-Mg-Si cast aluminum alloy) casting.

[0063] Figure 1 A comparison of the specific strength and fracture toughness of the alloys of the present invention (1#, 3#, 5#, 6#, 13#, 14#, 16#, 24#) and the alloys of non-the present invention (18#, 19#, 20#, 21#, 22#) is given. It can be seen that the alloys of the present invention have better mechanical property matching.

Claims

1. A lightweight, high-strength, high-toughness, high-magnesium-content Al-Mg-Zn aluminum alloy, characterized in that, The aluminum alloy contains: Al 84.84~90.88wt%, Mg 6.01~9.95wt%, Zn 3.01~3.99wt%, Si 0.025~0.099wt%, and at least one of Mn, Cu, Zr, Sc, Ti, Be, and Sb with a total content not exceeding 0.75wt%; the contents of Mg, Zn, and Si satisfy the following relationship: 2.80≤[(5×Mg)+Zn] / [(2×Si)+(3×Zn)]≤5.

78.

2. The lightweight, high-strength, high-toughness, high-magnesium-content Al-Mg-Zn aluminum alloy according to claim 1, characterized in that, The aluminum alloy contains: Al 85.65~89.88wt%, Mg 7.01~9.19wt%, Zn 3.01~3.99wt%, Si 0.025~0.099wt%, and at least one of Mn, Cu, Zr, Sc, Ti, Be, and Sb in total content not exceeding 0.7wt%. Preferably, the aluminum alloy contains: Al 85.65~89.38wt%, Mg 7.01~9.19wt%, Zn 3.51~3.99wt%, Si 0.025~0.099wt%, and at least one of Mn, Cu, Zr, Sc, Ti, Be, and Sb in a total content not exceeding 0.7wt%. Preferably, in the aluminum alloy, the contents of Mg, Zn and Si satisfy the following relationship: 3.21≤[(5×Mg)+Zn] / [(2×Si)+(3×Zn)]≤5.

39. Preferably, in the aluminum alloy, the contents of Mg, Zn and Si satisfy the following relationship: 3.21≤[(5×Mg)+Zn] / [(2×Si)+(3×Zn)]≤4.

67.

3. The lightweight, high-strength, high-toughness, high-magnesium-content Al-Mg-Zn aluminum alloy according to claim 2, characterized in that, The aluminum alloy contains: Mn 0.03~0.45wt%. Preferably, the aluminum alloy contains: Cu 0.02~0.60wt%. Preferably, the aluminum alloy contains 0.05~0.25wt% Zr. Preferably, the aluminum alloy contains: 0.02~0.25wt% Sc. Preferably, in the aluminum alloy, the contents of Sc and Zr satisfy: 0.12wt% ≤ (Sc+Zr)wt% ≤ 0.30wt%. Preferably, the aluminum alloy contains: Ti 0.001~0.11wt%. Preferably, in the aluminum alloy, the contents of Ti and Zr satisfy: 0.10wt% ≤ (Ti+Zr)wt% ≤ 0.30wt%. Preferably, the aluminum alloy contains: Be 0.0002~0.025wt%. Preferably, the aluminum alloy contains: Sb 0.005~0.025wt%.

4. The lightweight, high-strength, high-toughness, high-magnesium-content Al-Mg-Zn aluminum alloy according to claim 2, characterized in that, The aluminum alloy contains elements that were unintentionally introduced as impurities during the manufacturing process of the alloy ingot, wherein Fe ≤ 0.30 wt%, each of the other impurity elements ≤ 0.20 wt%, and the total ≤ 0.45 wt%. Preferably, the aluminum alloy contains elements that were unintentionally introduced as impurities during the manufacturing process of the alloy ingot, wherein Fe ≤ 0.20 wt%, each of the other impurity elements ≤ 0.10 wt%, and the total ≤ 0.28 wt%. Preferably, in the aluminum alloy, Fe ≤ 0.18 wt%.

5. A method for producing wrought aluminum alloy materials, characterized in that, Includes the following steps: (1) Manufacturing an ingot of the aluminum alloy according to any one of claims 1 to 4; (2) The resulting ingot is subjected to homogenization heat treatment and / or preheating; (3) The ingot is hot-deformed into the required form of the material by one or more hot deformation processing methods selected from extrusion, rolling and forging, or hot-deformed into a pre-processed material; (4) Optionally, the pre-processed material can be reheated and then cold-deformed into the required material form; (5) Perform solution heat treatment on the processed material; (6) Rapidly cool the solution-treated material to room temperature; and (7) The cooled processed material is subjected to natural aging or artificial aging treatment to obtain aged processed material.

6. The method according to claim 5, characterized in that, In step (1), the ingot is manufactured by smelting, degassing, removing inclusions and semi-continuous casting. During the smelting process, the content of elements is precisely controlled with Mg and Zn as the core. Through online component detection and analysis, the ratio between alloying elements is quickly supplemented and adjusted, and the entire ingot manufacturing process is completed. Preferably, in step (1), 0.001~0.11wt% of Ti is added in the form of an Al-Ti master alloy during smelting to refine the grain size. Preferably, in step (1), 0.0002~0.025wt% Be is added in the form of an Al-Be master alloy during smelting to change the properties of the oxide film and reduce oxidation loss and inclusions. Preferably, in step (1), 0.005~0.025% Sb is added in the form of an Al-Sb master alloy during smelting to neutralize alkali metal impurities such as Na in the alloy, improve the surface quality of the ingot, and enhance the hot working plasticity of the alloy. Preferably, step (1) further includes applying an electromagnetic field, an ultrasonic field, or mechanical stirring to or near the crystallizer. Preferably, in step (2), the homogenization heat treatment is performed by means selected from the group consisting of: (1) A single-stage homogenization heat treatment with a total time of 10 to 80 hours was performed in the range of 390 to 480℃; and (2) Perform two-stage or multi-stage homogenization heat treatment for a total time of 10 to 60 hours in the range of 390 to 500℃. Preferably, in steps (3) and (4), the preheating temperature and reheating temperature before each hot deformation process are 350~430℃, and the processing time is 1~5h. Preferably, in step (4), an intermediate annealing treatment of 350~420℃ / 0.5~8h is added between cold deformation passes. Preferably, in step (5), the solution heat treatment needs to further adjust the subgrain size, recrystallization size, and ratio in the material according to performance requirements, and is carried out by means selected from the following group: (1) Perform single-stage, double-stage or multi-stage solution heat treatment with a total time of 0.5 to 8 hours in the range of 420 to 500℃; and (2) A continuous heating solution heat treatment with a total time of 0.5 to 6 hours is carried out in the range of 420 to 500℃. Preferably, continuous heating solution heat treatment is used, with a heating rate ≤60℃ / min. Preferably, in step (6), the workpiece is rapidly cooled to room temperature using a method selected from cooling medium spray quenching, immersion quenching, forced air cooling, and combinations thereof. Preferably, in step (7), the artificial aging heat treatment is performed by means selected from the group consisting of: (1) After quenching and cooling, allow the material to age naturally at room temperature for ≥24 hours; (2) Within 2 hours after quenching and cooling, perform artificial aging treatment at 80~180℃ for a total time of 4~50 hours; and (3) After quenching and cooling, natural aging and artificial aging are combined. The artificial aging temperature is 90~180℃ and the time is 4~50h. Preferably, between steps (6) and (7), the following steps are also included: straightening and / or pre-deformation of the cooled processed material, using roller straightening, tension straightening, tension bending straightening and combinations thereof to straighten the material to improve its flatness, and using tension, compression and combinations thereof to pre-deform the material to reduce the residual stress formed by quenching and cooling, so as to facilitate subsequent processing and application. Preferably, the processed material is an extruded material, a sheet material, or a forging product.

7. The lightweight, high-strength, high-toughness, high-magnesium-content Al-Mg-Zn aluminum alloy according to any one of claims 1 to 4, or the lightweight, high-strength, high-toughness, high-magnesium-content Al-Mg-Zn aluminum alloy manufactured by the method according to any one of claims 5 to 6, characterized in that, The density of the aluminum alloy is ≤2.70 g / cm³. 3 Tensile strength ≥ 450 MPa, fracture toughness ≥ 32.0 MPa·m 1 / 2 . Preferably, the density of the aluminum alloy is ≤2.69 g / cm³. 3 Tensile strength ≥ 470 MPa, fracture toughness ≥ 34.0 MPa·m 1 / 2 . Preferably, the density of the aluminum alloy is ≤2.68 g / cm³. 3 Tensile strength ≥ 490 MPa, fracture toughness ≥ 36.0 MPa·m 1 / 2 .

8. A method for producing cast aluminum alloy, characterized in that, Includes the following steps: (1) The aluminum alloy castings of any one of the aluminum alloys described in claims 1 to 4 are prepared by smelting, degassing, removing inclusions and casting with sand molds, metal molds or die casting. During the smelting process, the element content is precisely controlled with Mg and Zn as the core. The ratio between alloy elements is quickly supplemented and adjusted through online component detection and analysis, and the entire casting preparation process is completed. (2) Solution heat treatment of the obtained aluminum alloy castings: including single-stage, double-stage or multi-stage solution heat treatment of aluminum alloy castings in the range of 420~500℃ for a total time of 0.5~8h, or continuous heating solution heat treatment of aluminum alloy castings in the range of 420~500℃ for a total time of 0.5~6h. (3) Perform natural aging or artificial aging heat treatment on aluminum alloy castings; natural aging is carried out at room temperature for ≥24h; artificial aging is carried out in the range of 80~180℃ for a total time of 4~50h; or a combination of natural aging and artificial aging is used, with artificial aging temperature of 80~180℃ and time of 4~50h.

9. A product characterized in that, It is a product formed by bonding together the lightweight, high-strength, high-toughness, high-magnesium-content Al-Mg-Zn aluminum alloy manufactured according to any one of claims 1 to 4 and 7 or the lightweight, high-strength, high-toughness, high-magnesium-content Al-Mg-Zn aluminum alloy manufactured by the method according to any one of claims 5 to 6 and 8 with itself or other alloys.

10. A final component, characterized in that, The lightweight, high-strength, high-toughness, and high-magnesium-content Al-Mg-Zn aluminum alloy manufactured according to any one of claims 1 to 4 and 7, or the lightweight, high-strength, high-toughness, and high-magnesium-content Al-Mg-Zn aluminum alloy manufactured by the method according to any one of claims 5 to 6 and 8, is processed into a final component. Preferably, the final component is a load-bearing structural member.

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