Lightweight, high-strength, corrosion-resistant aluminum alloy material and its manufacturing method

Abstract

This paper discloses a lightweight, high-strength, corrosion-resistant aluminum alloy material containing 6.0-10.0 wt% Mg, 1.0-3.5 wt% Zn, 0.1-1.3 wt% Si, and a total of 0.8 wt% or less of at least one element selected from Mn, Cu, Zr, Sc, and Ti, with the balance being Al and unavoidable impurities. It also discloses a manufacturing method for a wrought aluminum alloy material, a manufacturing method for an aluminum alloy casting, the product, and the final component. This aluminum alloy material exhibits excellent low density, high strength, corrosion resistance, and damage resistance.

Description

[Technical Field]

[0001] This application claims priority to a Chinese patent application filed on March 6, 2023, bearing application number 202310201048.8, the entire disclosure of which is incorporated herein by reference.

[0002] The present invention relates to the field of aluminum alloys and their manufacturing and processing technologies, particularly to Al-Mg-Zn-Si aluminum alloys. More specifically, the present invention relates to lightweight, high-strength, corrosion-resistant Al-Mg-Zn-Si aluminum alloy materials and methods for manufacturing the same. [Background technology]

[0003] Aluminum alloys are characterized by their low specific gravity, high specific strength, ease of processing, and low cost, which makes them widely used in fields such as aerospace and transportation. To better support the lightweight design of aluminum alloy structural parts, there is a need to further develop new aluminum alloys with properties such as low density, high strength, corrosion resistance, and damage resistance.

[0004] Currently available wrought aluminum alloys mainly include the 2xxx series (Al-Cu-Mg), 3xxx series (Al-Mn), 4xxx series (Al-Si), 5xxx series (Al-Mg), 6xxx series (Al-Mg-Si), and 7xxx series (Al-Zn-Mg-Cu) aluminum alloys. Among them, the 5xxx series aluminum alloys (Al-Mg aluminum alloys) contain Mg as the main alloying element and have moderate strength, excellent corrosion resistance, and excellent weldability, making them the second most popular aluminum alloy variety after the 6xxx series. The Al-Mg aluminum alloys commonly used both domestically and internationally include 5052, 5056, 5083, 5182, 5A02, and 5A06, whose magnesium content is generally in the range of 2.5 to 5.5 wt%. These alloys have the highest magnesium content and lowest density of all commercially available wrought aluminum alloys, and the density decreases by nearly 0.4% for every 1 wt% increase in magnesium content.

[0005] The difference in atomic radius between Mg and Al is 13%. Within the normal Mg content range (2.5–5.5 wt%), the main strengthening mechanism for Al-Mg-based aluminum alloys is the dissolution of Mg atoms into the Al matrix, resulting in lattice distortion, which strengthens the alloy and improves work hardening during deformation. However, as the Mg content increases beyond the normal range, the β-Al3Mg2 phase, which is incompatible with the matrix and cannot provide diffusion strengthening, precipitates in large quantities along the grain boundaries in a network-like pattern. Furthermore, because the β-phase has a self-corrosion potential of −1.085 V, which is lower than the self-corrosion potential of the α-Al matrix (−0.812 V), it corrodes faster than the matrix, resulting in severe exfoliation corrosion and intergranular corrosion. Therefore, simply increasing the Mg content in Al-Mg-based aluminum alloys to improve their strength generally results in a significant deterioration of the overall performance of the alloy. On the other hand, if the formation of the β phase that precipitates in a network pattern along the grain boundaries can be effectively suppressed by increasing the Mg content in Al-Mg aluminum alloys and adding appropriate alloying elements to form a precipitation-strengthening phase with the excess Mg, it will be possible to significantly improve the strength of Al-Mg aluminum alloys while maintaining their low density characteristics and avoid serious deterioration in corrosion resistance.

[0006] In order to realize aging precipitation strengthening in Al-Mg based aluminum alloys, previous research has been conducted by adding two alloying elements, Ag and Zn, to form the precipitation strengthening phase, T-Mg. 32 (Al, Ag) 49 and T-Mg 32 (Al, Zn) 49 Since the 1960s, it has been reported that adding trace amounts of Ag to Al-Mg alloys results in the formation of the precipitation-strengthening phase T-Mg. 32 (Al, Ag) 49 The orientation relationship between the T phase and the α-Al matrix becomes (010) T / / (112) α and (001) T / / (110) αIt has been discovered and confirmed that the lattice constant is a = 1.41 nm. The addition of Ag can effectively improve the precipitation strengthening response of Al-Mg alloys, and a reasonable combination of pretreatment and aging treatment can provide Al-Mg-Ag alloys with a good match between strength and plasticity. However, the high cost of Ag makes it difficult to mass-produce in industrial production. Since the beginning of the 21st century, some research has shown that when Zn is added to conventional Al-Mg-based aluminum alloys, a precipitated phase called T-Mg is formed from the alloy grain interior to the grain boundary by toughening heat treatment. 32 (Al, Zn) 49It has been found that this can form a β-phase and suppress the formation of β-phase, thereby effectively improving the strength of Al-Mg aluminum alloys, avoiding serious deterioration of corrosion resistance, and demonstrating its important application value.For example, Patent Document CN104694800A discloses a high-strength, lightweight Al-Mg-Zn alloy, whose basic composition ranges are Mg: 6.0-10.0 wt%, Zn: 3.0-5.0 wt%, Cu<2.0 wt%, Mn<1.2 wt%, Fe<0.3 wt%, Si<0.3 wt%, and at least one element selected from the group consisting of Cr, Ti, Zr, Sc, Hf, La, Ce, Pr, and Nd, with the addition of less than 0.5 wt% of any single element, and the tensile strength of this alloy in the T6 state exceeds 530 mPa. Patent document CN104862551A discloses an Al-Mg-Cu-Zn aluminum alloy and a method for manufacturing the aluminum alloy sheet, whose basic composition ranges are Mg: 4.0-6.0 wt%, Cu: 0.30-1.0 wt%, Zn: 1.0-3.5 wt%, Mn≦0.4 wt%, Fe≦0.4 wt%, Si≦0.4 wt%, Cr≦0.2 wt%, Ti≦0.1 wt%, and the balance being Al and unavoidable impurities. This alloy is a combination of AA5182 and AA5023 alloys, with an increased Cu content and the addition of Zn, thereby making full use of the precipitation strengthening properties of the S-phase transition phase in the Al-Mg-Cu system and the T-phase transition phase in the Al-Mg-Zn system. Its use in automotive interior panels can achieve significant strength improvements after a 30-minute baking process at 180°C. Patent document CN110541096A discloses a high-strength, easily weldable Al-Mg-Zn-Cu alloy and its manufacturing method, in which the ranges of its basic components are Mg: 4.3-7.0 wt%, Zn: 2.5-5.0 wt%, Cu: 0.4-1.2 wt%, Mn≦0.3 wt%, Cr≦0.1 wt%, Ti≦0.2 wt%, Zr≦0.3 wt%, and the balance is Al and unavoidable impurities, with a Zn / Mg mass ratio of 1.0 or less, and the strength of this alloy is approximately equivalent to that of conventional 7xxx series aluminum alloys.Patent document CN103866167A discloses an aluminum alloy, its alloy sheet, and a method for manufacturing the alloy sheet, whose basic components are in the range of Mg: 5.5-6.0 wt%, Zn: 0.6-1.2 wt%, Cu: 0.1-0.2 wt%, Mn: 0.6-1.0 wt%, Zr: 0.05-0.25 wt%, Cr≦0.1 wt%, Ti≦0.15 wt%, Fe≦0.25 wt%, Si≦0.2 wt%, and the balance is Al. The addition of Zn to this alloy significantly reduces the ability of Al3Mg2 to continuously precipitate at grain boundaries, and the alloy exhibits higher strength and corrosion resistance than conventional AA5059-H321 and AA5059-H131 sheets. Patent CN104152759A discloses a high-strength, corrosion-resistant Al-Mg alloy and its manufacturing process, whose basic components are Mg: 5.0-6.5 wt%, Zn: 1.2-2.5 wt%, Mn: 0.4-1.2 wt%, Zr: 0.05-0.25 wt%, Cu≦0.4 wt%, Cr≦0.1 wt%, Ti≦0.15 wt%, Fe≦0.4 wt%, Si≦0.4 wt%, and the remainder is Al and unavoidable impurities. Compared to conventional marine aluminum alloys such as AA5083 and AA5059, this alloy has significantly improved intergranular corrosion resistance while maintaining certain mechanical properties and exfoliation corrosion resistance. Patent document CN114438356A discloses a high-strength, high-toughness, corrosion-resistant Al-Mg-Zn-Ag(-Cu) aluminum alloy, whose basic components are Mg: 4.0-6.5 wt%, Zn: 3.0-5.5 wt%, Ag: 0.05-0.8 wt%, Cu≦1.0 wt%, Mn≦0.15 wt%, Ti≦0.15 wt%, Zr≦0.20 wt%, and the balance is Al and unavoidable impurities. This alloy has improved strength and a grade 3 intergranular corrosion resistance.

[0007] While research and development of Al-Mg-Zn alloys has achieved some success in recent years, there is still room for improvement in achieving a good match between key alloy properties, such as low density, high strength, corrosion resistance, and damage resistance. For example, most research still focuses on adding elements such as Zn to Al-Mg alloys based on normal (or slightly higher) Mg content ranges. While this results in improved alloy strength, the addition of high-density Zn and other elements results in Al-Mg alloys losing their inherent low density, making their strength-to-weight ratio less competitive than traditional 2xxx and 7xxx aluminum alloys. Furthermore, in some studies of high-Mg-content Al-Mg alloys, the types and amounts of added alloying elements have not been rationalized, resulting in the precipitation of a large amount of β-Al3Mg2 phase, distributed in a network pattern along the grain boundaries, resulting in poor corrosion resistance.

[0008] Therefore, further research and development is needed into novel Al-Mg based aluminum alloys that offer an excellent combination of key properties such as low density, high strength, corrosion resistance, and damage tolerance. Summary of the Invention [Problem to be solved by the invention]

[0009] Through extensive research and industrial practice, the present invention has found that existing Al-Mg-Zn aluminum alloys mainly use Mg and Zn as the main strengthening components, while Mg 32 (Al, Zn) 49It has been found that the β-Al3Mg2 phase is the main strengthening phase, and the precipitation sequence and type of the main strengthening phase are relatively uniform, making it difficult to achieve the ideal combination of lightweight, high strength, corrosion resistance, and damage resistance. In existing Al-Mg-Zn aluminum alloys, significantly increasing the Mg content and adding an appropriate amount of Si as a major alloying element can further reduce the alloy's weight while increasing the number of new aging precipitation sequences, significantly improving the alloy's aging strengthening response. Furthermore, the formation of the β-Al3Mg2 phase after a significant increase in Mg content can be further suppressed, effectively preventing the deterioration of the alloy's corrosion resistance. Furthermore, fine-alloying with elements such as Zr, Mn, Sc, and Cu as an auxiliary means contributes to the refinement of the material structure, strengthening the precipitation phase, and improving the material properties. Carefully optimizing the alloy's composition range and the composition ratio of each element is an important measure to ensure an excellent combination of performance. Rational design can ensure the alloy's lightweight while also increasing the Mg content during aging. 32 (Al, Zn) 49 The Al-Mg-Zn-Si alloy of the present invention can be made to have high toughness and good corrosion resistance by synergistically precipitating the precipitation strengthening phases of Al and MgSi structures and reducing the precipitation of excessive β-AlMg phase in the high Mg case.

[0010] The purpose of this invention is to overcome the lack of matching of the overall performance of existing Al-Mg-Zn aluminum alloy materials, and to further improve the matching of the overall performance of existing alloys through the optimal design of the components and manufacturing and processing processes, thereby providing the high-end manufacturing industry with an ideal lightweight Al-Mg-Zn-Si aluminum alloy material that combines strength, toughness, and corrosion resistance.

[0011] The first technical problem to be solved by the present invention is to propose an aluminum alloy material that is lightweight, high-strength, corrosion-resistant, and damage-resistant. The second technical problem to be solved by the present invention is to propose a method for manufacturing the aluminum alloy material. The third technical problem to be solved by the present invention is to propose welding the aluminum alloy material to itself or to other alloys to form new products. The fourth technical problem to be solved by the present invention is to propose processing the aluminum alloy material into final parts by various surface treatments, press forming, and machining methods. The fifth technical problem to be solved by the present invention is to propose uses of the final parts. [Means for solving the problem]

[0012] The present invention relates to a lightweight, high-strength, corrosion-resistant aluminum alloy material containing 6.0 to 10.0 wt% Mg, 1.0 to 3.5 wt% Zn, 0.1 to 1.3 wt% Si, and at least one element selected from Mn, Cu, Zr, Sc, and Ti in total of 0.8 wt% or less, with the balance being Al and unavoidable impurities.

[0013] In a first preferred embodiment of the present invention, the aluminum alloy contains 6.3 to 9.9 wt% Mg, 1.1 to 2.9 wt% Zn, 0.15 to 1.0 wt% Si, and at least one element selected from Mn, Cu, Zr, Sc, and Ti in a total amount of 0.6 wt% or less, with the remainder being Al and inevitable impurities.

[0014] In a second preferred embodiment of the present invention, the aluminum alloy contains 6.6 to 9.0 wt% of Mg, 1.3 to 2.9 wt% of Zn, and 0.15 to 0.8 wt% of Si.

[0015] In a third preferred embodiment of the present invention, the aluminum alloy contains 7.1 to 8.8 wt% of Mg, 1.5 to 2.8 wt% of Zn, and 0.25 to 0.7 wt% of Si.

[0016] In a fourth preferred embodiment of the present invention, the aluminum alloy contains 7.3 to 8.5 wt% of Mg, 1.5 to 2.7 wt% of Zn, and 0.4 to 0.6 wt% of Si.

[0017] In a fifth preferred embodiment of the present invention, the contents of Mg, Zn and Si in the aluminum alloy satisfy the relation 2.5≦(9×Mg) / [(1×Si)+(8×Zn)]≦6.

[0018] In a sixth preferred embodiment of the present invention, the aluminum alloy contains 0.10 to 0.50 wt% of Mn.

[0019] In a seventh preferred embodiment of the present invention, the aluminum alloy contains 0.10 to 0.50 wt % of Cu.

[0020] In an eighth preferred embodiment of the present invention, the aluminum alloy contains 0.01 to 0.15 wt % of Ti.

[0021] In a ninth preferred embodiment of the present invention, the aluminum alloy contains 0.05 to 0.25 wt % of Zr.

[0022] In a tenth preferred embodiment of the present invention, the aluminum alloy contains 0.05 to 0.30 wt% of Sc, and preferably simultaneously contains 0.05 to 0.20 wt% of Zr, and more preferably the total content of Sc and Zr satisfies 0.15 wt%≦(Sc+Zr)wt%≦0.35 wt%.

[0023] In an eleventh preferred embodiment of the present invention, the unavoidable impurities contained in the aluminum alloy include elements unintentionally mixed as impurities during the production of the alloy ingot, and should satisfy the following: Fe≦0.40 wt%, other impurity elements ≦0.20 wt% each, and a total of ≦0.50 wt%, preferably satisfying Fe≦0.20 wt%, other impurity elements ≦0.10 wt% each, and a total of ≦0.25 wt%, and more preferably satisfying Fe≦0.10 wt%.

[0024] The present invention further relates to a method for producing the aluminum alloy material, which can be described as follows: "preparation of alloy and melt smelting - production of ingot by semi-continuous casting - homogenization heat treatment of ingot - hot deformation - (intermediate annealing) - (cold deformation) - solution treatment - (pre-deformation or straightening) - aging treatment - product for shipment," and the basic production process for the aluminum alloy casting can be described as follows: "preparation of alloy and melt smelting - casting of casting - solution treatment - aging treatment - product for shipment."

[0025] The manufacturing method for the forged aluminum alloy material includes the following steps: (1) Producing an ingot by the semi-continuous casting method according to the present invention (2) A step of subjecting the obtained ingot to homogenization heat treatment and / or preheating. (3) hot deforming the ingot into the shape of a desired work material or into a pre-processed material by one or more hot deformation processes selected from extrusion, rolling, and forging; (4) Optionally, reheat treating and cold deforming the pre-treated material into the desired workpiece shape. (5) solution heat treating the processed material (6) Rapidly cooling the solution-heat-treated workpiece to room temperature. (7) Aging the cooled workpiece naturally or artificially to obtain an aged workpiece of the alloy.

[0026] In step (1), ingots are produced by melting, degassing, inclusion removal, and semi-continuous casting. During the melting and refining process, the element contents, primarily Mg and Zn, are precisely controlled, and the alloying element ratios are quickly adjusted through online element detection and analysis. Preferably, 0.0002-0.005 wt% Be is added during the melting and refining process in the form of an Al-Be intermediate alloy to modify the oxide film properties and reduce oxidation burns and inclusions. Also preferably, step (1) includes applying an electromagnetic field, ultrasonic field, or mechanical stirring at or near the crystallization site.

[0027] In step (2), the homogenization heat treatment is carried out by one of the following methods: (1) a single-stage homogenization heat treatment at 360 to 490°C for a total of 12 to 60 hours, and (2) a two-stage or multi-stage homogenization heat treatment at 360 to 500°C for a total of 12 to 60 hours.

[0028] In steps (3) and (4), the preheating temperature and reheating temperature before each hot deformation process are 370-460°C, and the processing time is 1-8 hours. Preferably, an intermediate annealing treatment at 350-450°C / 0.5-6 hours is added between cold deformation passes.

[0029] In step (5), the solution heat treatment is required to further adjust and control the subgrain size and recrystallized structure ratio of the material depending on the performance requirements, and is performed by selecting from the following methods: (1) a one-stage, two-stage, or multi-stage solution heat treatment at 440 to 500°C for a total of 0.5 to 8 hours, or (2) a continuous temperature increase solution heat treatment at 440 to 500°C for a total of 0.5 to 5 hours. Preferably, a continuous temperature increase solution heat treatment is used, with a heating rate of 60°C / min or less.

[0030] In step (6), the workpiece is rapidly cooled to room temperature using a means selected from coolant spray quenching, immersion quenching, air blast cooling, and combinations thereof.

[0031] In step (7), the artificial aging heat treatment is carried out by selecting from the following methods: (1) natural aging at room temperature after quenching is completed, for a time period of ≥ 48 hours; (2) artificial aging at 70-240°C within 2 hours after quenching is completed, for a total time period of ≥ 6-60 hours; (3) a combination of natural aging and artificial aging after quenching is completed, for which the artificial aging temperature is 70-240°C and the time period is 6-60 hours.

[0032] Between steps (6) and (7), a step of straightening and / or pre-deforming the cooled workpiece may be further included, in which straightening is performed using roll straightening, stretch straightening, stretch-bending straightening, or a combination thereof to improve the straightness of the workpiece, and pre-deforming is performed using tension, compression, or a combination thereof to remove residual stress formed by quenching in order to facilitate subsequent processing and use. [Effects of the Invention]

[0033] According to the manufacturing method of the present invention, the workpiece material is a wire, a bar, a tube, a sheet, a thick plate, or a forging.

[0034] The lightweight, high-strength, corrosion-resistant aluminum alloy material of the present invention has a density of ≦2.68 g / cm 3 Preferably, the aluminum alloy material has a density of 2.66 g / cm3 or less, a tensile strength of 400 MPa or more, and an exfoliation corrosion resistance of EA grade or higher. 3 , tensile strength ≧ 410 MPa, and exfoliation corrosion resistance is EA grade or higher. More preferably, the aluminum alloy material has a density ≦ 2.64 g / cm 3 The tensile strength is ≧420MPa, and the exfoliation corrosion resistance is PC grade or higher.

[0035] The present invention relates to a method for manufacturing the aluminum alloy casting, which comprises the following steps: (1) producing aluminum alloy castings by means of melting, degassing, removing inclusions, and sand casting, permanent mold casting, or pressure casting; Furthermore, in the melting and smelting process, Mg and Zn are the core, and the element content is precisely controlled. Through online component detection and analysis, the alloy element ratio can be quickly supplemented or adjusted to complete the entire casting manufacturing process. (2) A step of subjecting the obtained aluminum alloy casting to a solution heat treatment, including subjecting the aluminum alloy casting to a one-stage, two-stage, or multi-stage solution heat treatment at 440 to 500°C for a total of 0.5 to 8 hours, or subjecting the aluminum alloy casting to a continuous temperature-rising solution heat treatment at 440 to 500°C for a total of 0.5 to 5 hours. (3) A step of subjecting the aluminum alloy casting to natural aging at room temperature for 48 hours or more, artificial aging heat treatment at 70 to 240°C for a total of 6 to 60 hours, or a combination of natural aging and artificial aging at 70 to 240°C for 6 to 60 hours.

[0036] The aluminum alloy material described in this invention can be welded with itself or with other alloys to form new products, including friction stir welding, fusion welding, brazing, electron beam welding, and laser welding, and can be processed into final components, which are load-bearing structural components, by various surface treatments, press forming, and machining methods.

[0037] The beneficial effects of the present invention are as follows: (1) By optimizing the composition design of Al-Mg-Zn-Si aluminum alloys and using suitable manufacturing methods, high Mg content and Mg 32 (Al, Zn) 49 The synergistic strengthening of the precipitation sequence of the Mg2Si structural phase and the Mg2Si structural phase during two-stage aging has been achieved, significantly improving the alloy's strengthening response, and the material has high strength and toughness while maintaining light weight and good corrosion resistance. The material exhibits excellent comprehensive performance, making it ideal for all types of load-bearing structural parts and can meet the strict requirements for lightweight, high-performance aluminum alloys in all types of high-end manufacturing.

[0038] (2) By adding the alloying element Si, the present invention not only achieves the introduction of a new aging sequence of the Mg2Si structural phase, but also provides a basis for further increasing the Mg content in Al-Mg-based aluminum alloys, further exploiting the aging strengthening potential of the alloys, and promoting the development of lightweighting in fields such as aerospace, transportation, automobiles and ships, with important social and economic benefits.

[0039] (3) The material of the present invention has excellent performance, reasonable price, simple and practical manufacturing method, strong operability, easy industrialization and popularization, and market prospects.

[0040] In order to more clearly describe the technical solutions of the embodiments of the present application, the drawings of the embodiments will be briefly described below. Of course, the drawings described below only relate to some embodiments of the present application and do not limit the present disclosure. [Brief explanation of the drawings]

[0041] [Figure 1] 1 is a TEM image of the intragranular precipitate phase in the aged state of the 22# alloy in Example 2 of the present invention. [Figure 2] 1 is a TEM image of a grain boundary precipitate phase in an aged state of the 22# alloy in Example 2 of the present invention. [Figure 3] 1 is a comparison of the specific strength and fracture toughness of the alloy of the present invention and a typical conventional alloy. [Figure 4] 1 is a comparison of the specific strength and corrosion resistance of the alloy of the present invention with a typical conventional alloy. DETAILED DESCRIPTION OF THE INVENTION

[0042] The technical solution of the present invention will be further described in detail below with reference to the examples.

[0043] Example 1 To demonstrate the principles of the present invention, alloy extrusion strips were prepared on a laboratory scale. The experimental alloy compositions are shown in Table 1.

[0044] Using industry-known methods such as alloy melting, degassing, and inclusion removal, a 210mm diameter round ingot was produced, simulating the conditions of semi-continuous casting. The ingot was then subjected to a homogenization heat treatment at 400±5°C for 12 hours and 475±5°C for 24 hours, followed by air cooling. After stripping, face milling, and sawing, a 180mm diameter extruded ingot was obtained. This ingot was preheated at 440±10°C for 4 hours and extruded to produce a 25×100mm strip. The extrusion temperature was controlled at approximately 400°C. The extruded strips were placed in an air furnace at 450°C and subjected to continuous solution heat treatment at 450-480°C for a total of 90 minutes. Immediately after water quenching, they were subjected to 1.5-2% tension straightening, and then to two-stage aging treatment at 90±5°C / 24 hours + 140±5°C / 22-26 hours depending on the alloy properties.

[0045] Samples were cut according to the relevant methods, and the alloys were evaluated for density (GB / T 1423), tensile properties (GB / T 16865), fracture toughness (GB / T 4161), fatigue properties (GB / T 3075), exfoliation corrosion (GB / T 22639) and intergranular corrosion according to the relevant test standards to evaluate the alloys as commonly used performance indexes, and the results are shown in Table 2.

[0046] [Table 1]

[0047] [Table 2]

[0048] As can be seen from the above table, alloys 1#, 2#, 3#, 4#, 5#, 6#, 7#, 8#, 9#, 10#, 11#, 12#, 13# and 14# all have good matching in density, strength, plasticity, fracture toughness, fatigue performance and corrosion resistance, with a density of 2.66g / cm 3 The tensile strength was maintained at 430 MPa or more, the elongation at break was over 11.0%, and the fracture toughness was 31.0 MPa m 1 / 2Under a constant stress of 241 MPa and a strain ratio of 0.1, all of the alloys passed a 12,000-cycle fatigue test, with exfoliation corrosion of grade N and intergranular corrosion of grade 3 or higher. The properties of alloys 15#, 16#, 17#, 18#, 19#, and 20# do not achieve a good match in density, strength, plasticity, fracture toughness, fatigue performance, and corrosion resistance. Alloy 15#, with its low Mg content, exhibits relatively low strength and poor corrosion resistance. Alloy 16#, with its low Mg and Zn contents, exhibits the lowest strength. Alloy 17#, with its high Mg content and low Zn content, exhibits severe corrosion resistance degradation. In contrast, alloy 18# has a low Mg content and a high Zn content, resulting in low elongation, reduced plasticity, poor corrosion resistance, and high density. Alloy 19# has a high Mg and Zn content, and although its strength is relatively high, its plasticity and corrosion resistance are severely deteriorated. Alloy 20# has a high Si content, resulting in poor plasticity and fatigue performance, and slightly reduced corrosion resistance.

[0049] Example 2 The aluminum alloy sheets were prepared in the laboratory. The alloy compositions are shown in Table 3.

[0050] Using industry-known methods such as alloy melting, degassing, and inclusion removal, 100mm-thick flat ingots were produced under semi-continuous casting conditions. All ingots underwent a three-stage homogenization heat treatment of (400±5°C / 12h), (475±5°C / 24h), and (500±5°C / 12h), followed by air cooling. After stripping, face milling, and sawing, 80mm-thick rolled ingots were obtained. These ingots were preheated at 450±10°C for 2 hours and bloomed at 440°C. They were first rolled across the width of the flat ingot for 3-4 passes, followed by an intermediate annealing treatment at 400±5°C / 2h. The rolling direction was then reversed and the flat ingots were rolled across the length to a thickness of approximately 20mm. The plates were placed in an air furnace at 450°C and subjected to solution heat treatment at 450°C for 30 minutes and 480°C for 60 minutes. Immediately after water quenching, they were subjected to a 2% pre-stretching treatment, and then to a two-stage aging treatment at 90±5°C for 24 hours and 140±5°C for 24 hours, respectively, according to the alloy properties.

[0051] Samples were cut according to the relevant methods, and the alloys were evaluated for density (GB / T 1423), tensile properties (GB / T 16865), fracture toughness (GB / T 4161), fatigue properties (GB / T 3075), exfoliation corrosion (GB / T 22639) and intergranular corrosion according to the relevant test standards to evaluate the alloys as commonly used performance indexes, and the results are shown in Table 4.

[0052] [Table 3]

[0053] [Table 4]

[0054] As can be seen from Table 4, the 21# and 22# alloys of the present invention both exhibit a good match between toughness and corrosion resistance, and are significantly superior to the 23# alloy without Si addition. Figures 1 and 2 show TEM images of the intragranular and intergranular precipitates of the 22# alloy, respectively. 32 (Al, Zn) 49It is clearly seen that the β′-Mg2Si phase and the β′-Mg2Si phase precipitated simultaneously in the alloy, and the grain boundary precipitated phases were distributed at intervals, which contributed to the alloy's high toughness and good corrosion resistance properties.

[0055] Example 3 Small aluminum alloy forgings were fabricated on a pilot-scale platform, with alloy compositions shown in Table 5.

[0056] Through industry-known methods such as alloy melting, degassing, and inclusion removal, a 530mm diameter round ingot was produced using a semi-continuous casting process. The ingot was then subjected to homogenization heat treatment under the following conditions: (400±5°C / 12h) + (475±5°C / 30h) + (500±5°C / 10h) followed by air cooling. After stripping, face milling, and sawing, a 490mm diameter extrusion blank was obtained. The blank was preheated at 440±10°C for 6 hours and extruded to obtain a 240mm diameter rod-shaped extrusion blank. Further, a 60×500×900mm small forging was obtained by multi-axis forging. The extrusion and forging temperatures were controlled between 400 and 420°C. The forgings were placed in an air furnace at 450°C and subjected to solution heat treatment at 450°C / 30 min + 480°C / 90 min. Immediately after water quenching, they were subjected to preliminary deformation treatment with 1.5-2.5% compression, and then to two-stage aging treatment at 90±5°C / 24 h + 140±5°C / 28 h.

[0057] Samples were cut according to the relevant methods, and the alloys were evaluated for density (GB / T 1423), tensile properties (GB / T 16865), fracture toughness (GB / T 4161), fatigue properties (GB / T 3075), exfoliation corrosion (GB / T 22639) and intergranular corrosion according to the relevant test standards to evaluate the alloys as commonly used performance indicators, and the results are shown in Table 6.

[0058] [Table 5]

[0059] [Table 6]

[0060] As can be seen from Table 6, the 24# alloy of the present invention exhibits a good match between toughness and corrosion resistance.

[0061] Example 4 Aluminum alloy castings were produced in the laboratory. The alloy compositions are shown in Table 7.

[0062] After preparing the raw materials (high-purity aluminum, pure magnesium, pure zinc, Al-Si intermediate alloy, Al-Zr intermediate alloy, Al-Ti-B intermediate alloy refiner), and baking the tools and molds, the high-purity aluminum is melted at 730°C, and the pure zinc, Al-Si intermediate alloy, and Al-Zr intermediate alloy are first added in the usual order and stirred until completely melted. The temperature is then lowered to 720°C, and the Al-Ti-B intermediate alloy is added. After stirring, the mixture is left to stand for 4 to 6 minutes, and the temperature is then lowered to 710°C. The pure magnesium wrapped in aluminum foil is then placed in a bell jar and melted into the aluminum. The alloy is forced into the alloy liquid, stirred until completely melted, and heated to 720°C, where it is refined to remove degassing and slagging, and then inspected before being placed in a furnace. After leaving it to stand for 30 minutes at a casting temperature of 690°C, the molten aluminum alloy is poured into a mold that has been baked to a temperature of approximately 180-200°C. The resulting aluminum alloy casting is placed in an air furnace at 470°C and subjected to solution heat treatment at 470±5°C / 12 hours + 485±5°C / 12 hours. After water cooling, it is left to stand and undergoes natural aging for 48 hours, followed by a two-stage aging treatment at 95±5°C / 12 hours + 150±5°C / 24 hours.

[0063] Samples were cut according to the relevant methods, and the alloys were evaluated for density (GB / T 1423), tensile properties (GB / T 16865), exfoliation corrosion (GB / T 22639) and intergranular corrosion according to the relevant test standards to evaluate the alloys as commonly used performance indicators, and the results are shown in Table 8.

[0064] [Table 7]

[0065] [Table 8]

[0066] As can be seen from Table 8, the 25# alloy of the present invention exhibits high levels of strength and a good match between high plasticity and corrosion resistance compared to the 26# alloy (Al-Mg-Si cast aluminum alloy) castings.

[0067] Example 5 The alloys were produced on an industrial scale, and the alloy compositions are shown in Table 9.

[0068] Through industry-known methods such as alloy melting, degassing, and inclusion removal, 480mm diameter round ingots were produced using a semi-continuous casting process. The 27#, 28#, and 29# alloy ingots were homogenized at 405±5°C for 10 hours, 475±18°C for 18 hours, and 505±5°C for 12 hours. The other alloys were annealed at 470-500°C for 36 hours, followed by air cooling. After stripping, face milling, and sawing, 450mm diameter extrusion blanks were obtained. The blanks were preheated at 430±10°C for 4 hours and then extruded to produce large extruded strips measuring 35×400mm. The extrusion temperature was controlled at approximately 380±10°C. According to the properties of the alloy itself, appropriate process parameters are selected in the range of 475~540℃ to subject the alloy strip to solution heat treatment, followed by 1.5~2% tensile straightening immediately after water quenching, followed by typical aging treatment. 27#, 28#, and 29# alloys are subjected to two-stage aging treatment of 90±3℃ / 24h + 140±3℃ / 24h, 30# alloy is subjected to aging treatment of 121±5℃ / 6h + 163±5℃ / 20h, 31# alloy is subjected to aging treatment of 190±5℃ / 12h, and 32# alloy is subjected to aging treatment of 165±5℃ / 8h, thereby achieving good matching of the alloy materials' comprehensive performance.

[0069] Samples were cut according to the relevant methods, and the alloys were evaluated for density (GB / T 1423), tensile properties (GB / T 16865), fracture toughness (GB / T 4161), fatigue properties (GB / T 3075), exfoliation corrosion (GB / T 22639) and intergranular corrosion according to the relevant test standards to evaluate the alloys as commonly used performance indexes, and the results are shown in Table 10.

[0070] [Table 9]

[0071] [Table 10]

[0072] As can be seen from Table 10, the 27#, 28#, and 29# alloys of the present invention all have low density and good matching of strength, toughness, and corrosion resistance. Compared with the 7050 alloy (30# alloy), 2024 alloy (31# alloy), and 6005A alloy (32# alloy) fabricated under the same conditions, they have clear advantages in terms of overall performance, with low density, high strength levels, and high fracture toughness, fatigue resistance, and corrosion resistance.

[0073] Figures 3 and 4 show comparisons of the specific strength, fracture toughness, and corrosion resistance of the alloys of the present invention, 27#, 28#, 29#, 7050 alloy (30# alloy), and 2024 alloy (31# alloy), with 6005A alloy (32# alloy). As can be seen from the figures, the alloy products of the present invention exhibit good matching of mechanical properties and corrosion properties.

[0074] The above descriptions are merely exemplary embodiments of the present disclosure and are not intended to limit the protection scope of the present disclosure, which is determined by the appended claims.

Claims

1. A lightweight, high-strength, corrosion-resistant aluminum alloy material characterized by containing 6.0 to 10.0 wt% Mg, 1.0 to 3.5 wt% Zn, 0.1 to 1.3 wt% Si, and at least one element selected from Mn, Cu, Zr, Sc, and Ti in a total amount of 0.8 wt% or less, with the balance being Al and inevitable impurities.

2. 2. The lightweight, high-strength, corrosion-resistant aluminum alloy material according to claim 1, characterized in that the aluminum alloy contains 6.3 to 9.9 wt% Mg, 1.1 to 2.9 wt% Zn, 0.15 to 1.0 wt% Si, and at least one element selected from Mn, Cu, Zr, Sc, and Ti in a total amount of 0.6 wt% or less, with the remainder being Al and unavoidable impurities.

3. 3. The lightweight, high-strength, corrosion-resistant aluminum alloy material according to claim 2, characterized in that the aluminum alloy contains 6.6 to 9.0 wt% Mg, 1.3 to 2.9 wt% Zn, and 0.15 to 0.8 wt% Si.

4. 3. The lightweight, high-strength, corrosion-resistant aluminum alloy material according to claim 2, characterized in that the aluminum alloy contains 7.1 to 8.8 wt% Mg, 1.5 to 2.8 wt% Zn, and 0.25 to 0.7 wt% Si.

5. 3. The lightweight, high-strength, corrosion-resistant aluminum alloy material according to claim 2, wherein the aluminum alloy contains 7.3 to 8.5 wt% Mg, 1.5 to 2.7 wt% Zn, and 0.4 to 0.6 wt% Si.

6. 3. The lightweight, high-strength, corrosion-resistant aluminum alloy material according to claim 2, wherein the contents of Mg, Zn, and Si in the aluminum alloy satisfy the relational expression 2.5≦(9×Mg) / [(1×Si)+(8×Zn)]≦6.

7. 3. The lightweight, high-strength, corrosion-resistant aluminum alloy material according to claim 2, wherein the aluminum alloy contains 0.10 to 0.50 wt % of Mn.

8. 3. The lightweight, high-strength, corrosion-resistant aluminum alloy material according to claim 2, wherein the aluminum alloy contains 0.10 to 0.50 wt % of Cu.

9. 3. The lightweight, high-strength, corrosion-resistant aluminum alloy material according to claim 2, wherein the aluminum alloy contains 0.01 to 0.15 wt % of Ti.

10. 3. The lightweight, high-strength, corrosion-resistant aluminum alloy material according to claim 2, wherein the aluminum alloy contains 0.05 to 0.25 wt % of Zr.

11. 3. The lightweight, high-strength, corrosion-resistant aluminum alloy material according to claim 2, wherein the aluminum alloy contains 0.05 to 0.30 wt % of Sc.

12. 12. The lightweight, high-strength, corrosion-resistant aluminum alloy material according to claim 11, wherein the aluminum alloy contains 0.05 to 0.20 wt % of Sc.

13. 13. The lightweight, high-strength, and corrosion-resistant aluminum alloy material according to claim 12, wherein the total content of Sc and Zr in the aluminum alloy satisfies the relationship 0.15 wt%≦(Sc+Zr) wt%≦0.35 wt%.

14. 3. The lightweight, high-strength, corrosion-resistant aluminum alloy material according to claim 2, wherein the inevitable impurities include elements unintentionally mixed as impurities during the production of an alloy ingot, and in the aluminum alloy, Fe≦0.40 wt%, other impurity elements each≦0.20 wt%, and a total of≦0.50 wt%.

15. The lightweight, high-strength, and corrosion-resistant aluminum alloy material according to claim 14, characterized in that the inevitable impurities include elements unintentionally mixed as impurities during the production of an alloy ingot, and in the aluminum alloy, Fe≦0.20 wt%, other impurity elements each≦0.10 wt%, and a total of≦0.25 wt%.

16. 16. The lightweight, high-strength, corrosion-resistant aluminum alloy material according to claim 15, wherein the aluminum alloy contains Fe≦0.10 wt%.

17. A method for producing a forged aluminum alloy material, comprising: (1) A step of producing an ingot of the aluminum alloy according to any one of claims 1 to 16; (2) subjecting the obtained ingot to homogenization heat treatment and / or preheating; (3) hot deforming the ingot into the shape of a desired work material or into a pre-processed material by one or more hot deformation processing methods selected from extrusion, rolling, and forging; (4) optionally reheat treating and cold deforming the pre-treated material into the desired workpiece shape; (5) subjecting the processed material to a solution heat treatment; (6) quenching the solution heat treated workpiece to room temperature; (7) A method for producing a forged aluminum alloy material, comprising the step of naturally or artificially aging the cooled workpiece to obtain an aged alloy workpiece.

18. 18. The method according to claim 17, characterized in that in step (1), the ingot is produced by means of melting, degassing, inclusion removal, and semi-continuous casting, and in the melting and refining process, the content of elements is precisely controlled, with Mg and Zn as the core, and the blending ratio between alloy elements is quickly supplemented and adjusted through online component detection and analysis, thereby completing the entire ingot production process.

19. 19. The method according to claim 18, wherein in step (1), 0.0002 to 0.005 wt % of Be is added in the form of an Al-Be intermediate alloy during smelting, thereby changing the properties of the oxide film and reducing oxidation burns and inclusions.

20. 20. The method of claim 18, further comprising applying an electromagnetic field, an ultrasonic field, or mechanical agitation at or near the crystallization site in step (1).

21. In step (2), the homogenization heat treatment is (1) A method of performing a single-stage homogenization heat treatment at 360 to 490°C for a total of 12 to 60 hours; (2) A two-stage or multi-stage homogenization heat treatment method at 360 to 500°C for a total of 12 to 60 hours. The method according to claim 17, characterized in that the method is performed by selecting from the following:

22. 18. The method according to claim 17, wherein in steps (3) and (4), the preheating temperature and reheating temperature before each hot deformation process are 370-460°C, and the treatment time is 1-8 hours.

23. The method according to claim 17, characterized in that in step (4), an intermediate annealing treatment of 350-450°C / 0.5-6h is added between passes of cold deformation.

24. In step (5), the solution heat treatment needs to further adjust and control the subcrystal size and recrystallized structure ratio of the material according to performance requirements; and (1) A method of performing a one-stage, two-stage, or multi-stage solution heat treatment at 440 to 500°C for a total of 0.5 to 8 hours; (2) A solution heat treatment method in which the temperature is continuously raised to 440-500°C for a total of 0.5-5 hours. The method according to claim 17, characterized in that the method is performed by selecting from the following:

25. 24. The method according to claim 23, characterized in that a solution heat treatment is used with a continuous temperature increase, the temperature increase rate being ≦60° C. / min.

26. 18. The method of claim 17, wherein in step (6), the workpiece is rapidly cooled to room temperature using a means selected from coolant spray quenching, immersion quenching, air blast cooling, and combinations thereof.

27. In step (7), the artificial aging heat treatment is (1) After quenching, natural aging is performed at room temperature for a time period of ≥ 48 h; (2) within 2 hours after the completion of quenching, artificial aging treatment is performed at 70 to 240 ° C for a total time of 6 to 60 h; (3) After hardening, natural aging and artificial aging are combined, with the artificial aging temperature being 70 to 240°C and the time being 6 to 60 hours. The method according to claim 17, characterized in that the method is performed by selecting from the following:

28. 18. The method according to claim 17, further comprising a step of straightening and / or pre-deforming the cooled workpiece between steps (6) and (7), wherein the straightening is performed using roll straightening, stretch straightening, stretch-bending straightening, or a combination thereof to improve the straightness of the workpiece, and the pre-deformation is performed using tension, compression, or a combination thereof to remove residual stresses formed by quenching in order to facilitate subsequent processing and use.

29. 18. The method of claim 17, wherein the workpiece is wire, bar, tube, sheet, plate, or forging.

30. The aluminum alloy material has a density of ≦2.68 g / cm ３ 30. A lightweight, high-strength, corrosion-resistant aluminum alloy material according to any one of claims 1 to 16, or a lightweight, high-strength, corrosion-resistant aluminum alloy material produced by the method according to any one of claims 17 to 29, wherein the aluminum alloy has a tensile strength of 400 MPa or more and an exfoliation corrosion performance of EA class or higher.

31. The aluminum alloy material has a density of ≦2.66 g / cm ３ 31. The lightweight, high-strength, corrosion-resistant aluminum alloy material according to claim 30, characterized in that it has a tensile strength of ≥ 410 MPa and exfoliation corrosion resistance of EA grade or above.

32. The aluminum alloy material has a density of ≦2.64 g / cm ３ 32. The lightweight, high-strength, corrosion-resistant aluminum alloy material of claim 31, characterized in that it has a tensile strength of ≥ 420 MPa and exfoliation corrosion resistance of PC grade or higher.

33. A method for manufacturing an aluminum alloy casting, comprising: (1) manufacturing an aluminum alloy casting of the aluminum alloy according to any one of claims 1 to 16 by means of melting, degassing, removing inclusions, and sand casting, metal mold casting, or pressure casting, in which in the melting and refining process, the content of elements is precisely controlled, with Mg and Zn as the core, and the compounding ratio between alloy elements is quickly supplemented or adjusted through online component detection and analysis, thereby completing the entire manufacturing process of the casting; (2) subjecting the obtained aluminum alloy casting to a solution heat treatment including one-stage, two-stage, or multi-stage solution heat treatment at 440 to 500°C for a total of 0.5 to 8 hours, or continuous temperature-rising solution heat treatment at 440 to 500°C for a total of 0.5 to 5 hours; (3) subjecting the aluminum alloy casting to natural aging at room temperature for 48 hours or more, artificial aging at 70 to 240°C for a total of 6 to 60 hours, or a combination of natural aging and artificial aging at 70 to 240°C for 6 to 60 hours; A method for producing an aluminum alloy casting, comprising:

34. A product characterized in that it is a product obtained by welding the lightweight, high-strength, corrosion-resistant aluminum alloy material according to any one of claims 1 to 16 and 30 to 32, or the lightweight, high-strength, corrosion-resistant aluminum alloy material produced by the method according to any one of claims 17 to 29 and 33, with itself or with other alloys, by welding such as friction stir welding, fusion welding, brazing, electron beam welding or laser welding.

35. A final part, characterized in that the lightweight, high-strength, corrosion-resistant aluminum alloy material according to any one of claims 1 to 16, 30 to 32, or the lightweight, high-strength, corrosion-resistant aluminum alloy material produced by the method according to any one of claims 17 to 29, 33, is processed into a final part by various surface treatments, press forming, and machining methods.

36. 36. A final member according to claim 35, wherein the final member is a load-bearing structural member.

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