High-toughness corrosion-resistant aluminum-magnesium composite sheet material, and preparation method and application thereof

Abstract

The application belongs to the technical field of metal composite materials, and provides a high-strength and high-toughness corrosion-resistant aluminum-magnesium composite plate and a preparation method and application thereof. The composite plate comprises a first aluminum alloy layer, a magnesium alloy layer and a second aluminum alloy layer which are sequentially stacked; the aluminum alloy layer comprises the following components: Mg 3.0-5.5%, Mn 0.3-1.2%, Si 0.1-0.4%, Fe 0.15-0.4%, Cu 0.05-0.75%, Sc 0.1-0.3%, and Al as the balance; and the magnesium alloy layer comprises the following components: Al 2.0-4.0%, Ca 1.5-4.0%, Mn 0.2-1.0%, Be 0.1-0.5%, Sn 0.5-2.0%, and Mg as the balance. The application effectively solves the problems of insufficient interface bonding strength and easy generation of brittle and hard second phases in the aluminum-magnesium composite material by reasonably setting alloy components and selecting an asynchronous rolling process.

Description

Technical Field

[0001] This invention relates to the field of metal composite materials technology, and in particular to a high-strength, tough, and corrosion-resistant aluminum-magnesium composite plate, its preparation method, and its application. Background Technology

[0002] Aluminum and magnesium alloys are widely used in aerospace, automotive manufacturing, and marine engineering due to their excellent lightweight properties, high specific strength, and corrosion resistance. Magnesium alloys, in particular, while generally having lower absolute strength than aluminum alloys, have a higher specific strength (strength to weight), making them ideal materials for high-performance applications requiring weight reduction. However, in certain complex operating environments, a single aluminum or magnesium alloy may not be able to simultaneously meet the multiple performance requirements of strength, toughness, corrosion resistance, and formability.

[0003] To address these performance shortcomings, aluminum-magnesium composites have gradually become a research and application hotspot. By combining aluminum and magnesium, it is hoped that the corrosion resistance of aluminum alloys and the high specific strength of magnesium alloys can be simultaneously utilized. However, traditional aluminum-magnesium composite sheet manufacturing methods (such as mechanical lamination and fusion processes) have significant deficiencies in interfacial bonding. In particular, during processing, brittle and hard second phases (such as Mg-Al intermetallic compounds) are easily formed at the aluminum-magnesium interface, which leads to a decrease in interfacial bonding strength and reduces the toughness and formability of the composite material. In addition, the significant differences in the physicochemical properties of aluminum and magnesium make it difficult to achieve good metallurgical bonding under high-temperature processing. Although existing technologies CN109702012, CN109433822, and CN110181227 have attempted to reduce the formation of brittle and hard second phases and improve interfacial bonding strength by adding specific alloying elements, adjusting the structure of the aluminum-magnesium interfacial interface, and optimizing rolling process parameters, they still face technical challenges and cannot simultaneously meet the multiple performance requirements of composite materials, including strength, toughness, corrosion resistance, and formability.

[0004] Therefore, developing an aluminum-magnesium alloy composite plate that can effectively reduce the formation of brittle and hard second phases at the aluminum-magnesium interface, improve the metallurgical bonding strength between the two, and possess good comprehensive performance remains a technical challenge in the field of materials. Summary of the Invention

[0005] The purpose of this invention is to provide a high-strength, tough, and corrosion-resistant aluminum-magnesium composite sheet, its preparation method, and its applications, solving the problems of insufficient interfacial bonding strength and the easy formation of brittle and hard second phases during processing in existing aluminum-magnesium composite materials. Through reasonable alloy composition design and processing technology, this invention significantly improves the metallurgical bonding performance between the aluminum and magnesium layers, enhances the mechanical properties and corrosion resistance of the material, and the resulting high-strength, tough, and corrosion-resistant aluminum-magnesium composite sheet is suitable for fields such as aerospace, automotive manufacturing, and marine engineering that require lightweight, high-strength, and highly corrosion-resistant materials.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0007] This invention provides a high-strength, tough, and corrosion-resistant aluminum-magnesium composite plate, which includes a first aluminum alloy layer, a magnesium alloy layer, and a second aluminum alloy layer stacked sequentially.

[0008] The first aluminum alloy layer and the second aluminum alloy layer independently contain the following components by mass fraction: Mg 3.0–5.5%, Mn 0.3–1.2%, Si 0.1–0.4%, Fe 0.15–0.4%, Cu 0.05–0.75%, Sc 0.1–0.3%, and Al balance;

[0009] The magnesium alloy layer contains the following components by mass fraction: Al 2.0–4.0%, Ca 1.5–4.0%, Mn 0.2–1.0%, Be 0.1–0.5%, Sn 0.5–2.0%, and Mg balance.

[0010] The present invention also provides a method for preparing the high-strength, tough, and corrosion-resistant aluminum-magnesium composite plate, comprising the following steps:

[0011] (1) Mix the components contained in the first aluminum alloy layer and perform a first smelting to obtain a first aluminum alloy; mix the components contained in the second aluminum alloy layer and perform a second smelting to obtain a second aluminum alloy; mix the components contained in the magnesium alloy layer under a protective atmosphere and perform a third smelting to obtain a magnesium alloy.

[0012] (2) The first aluminum alloy is subjected to a first solution treatment to obtain a first aluminum alloy layer; the second aluminum alloy is subjected to a second solution treatment to obtain a second aluminum alloy layer; the magnesium alloy is subjected to a third solution treatment to obtain a magnesium alloy layer.

[0013] (3) The first aluminum alloy layer, the magnesium alloy layer and the second aluminum alloy layer are stacked in sequence. After the stacking is completed, rolling and heat treatment are performed in sequence to obtain the high-strength, tough and corrosion-resistant aluminum-magnesium composite plate.

[0014] Preferably, in step (1), the temperatures of the first and second melting processes are independently 700–770°C, and the temperature of the third melting process is 680–750°C.

[0015] Preferably, in step (2), the temperature of the first solution treatment and the second solution treatment are independently 500-550°C, and the time of the first solution treatment and the second solution treatment is independently 2-12h.

[0016] The temperature of the third solution treatment is 450–500℃, and the time of the third solution treatment is 4–24 hours.

[0017] Preferably, in step (3), the thickness of the first aluminum alloy layer and the second aluminum alloy layer is 4 to 8 mm independently, and the thickness of the magnesium alloy layer is 6 to 10 mm.

[0018] Preferably, the number of rolling passes in step (3) is ≥2; the total rolling reduction is 50-85%;

[0019] The rolling reduction rate of the first pass is 50-75%, and the rolling temperature of the first pass is 400-480℃; the rolling reduction rate of the remaining passes is independently 10-15%, and the rolling temperature of the remaining passes is independently 400-490℃; the rolling temperature of the remaining passes is ≥ the rolling temperature of the first pass.

[0020] Preferably, in step (3), the upper rolling roll speed is 5-10 m / min, the lower rolling roll speed is 3-8 m / min, and the asynchronous ratio is 1.2-1.6.

[0021] Preferably, the heat treatment temperature in step (3) is 200-300℃ and the heat treatment time is 0.5-2h.

[0022] This invention also provides the application of the high-strength, tough, and corrosion-resistant aluminum-magnesium composite sheet in aerospace, automobile manufacturing, or marine engineering.

[0023] The beneficial effects of this invention are:

[0024] This invention provides a high-strength, tough, and corrosion-resistant aluminum-magnesium composite plate, comprising a first aluminum alloy layer, a magnesium alloy layer, and a second aluminum alloy layer stacked sequentially. The first and second aluminum alloy layers independently contain the following mass fractions: Mg 3.0–5.5%, Mn 0.3–1.2%, Si 0.1–0.4%, Fe 0.15–0.4%, Cu 0.05–0.75%, Sc 0.1–0.3%, and Al balance. The magnesium alloy layer contains the following mass fractions: Al 2.0–4.0%, Ca 1.5–4.0%, Mn 0.2–1.0%, Be 0.1–0.5%, Sn 0.5–2.0%, and Mg balance. In the aluminum alloy layer, scandium (Sc) effectively suppresses recrystallization by refining the grains, slows down the formation of brittle intermetallic compounds at the interface, and significantly improves the bonding strength of the aluminum-magnesium interface. Scandium's high-temperature stability ensures uniform interfacial bonding during rolling and heat treatment, reducing interfacial failure caused by stress concentration. The addition of copper (Cu) enhances the stability of the bonding zone through solid solution strengthening and interfacial interdiffusion, reducing the formation of brittle phases and making the interfacial reaction more uniform and controllable. Manganese (Mn) further inhibits the precipitation of undesirable brittle phases at the interface by forming stable Al6Mn compounds, improving overall corrosion resistance and durability. In the magnesium alloy layer, calcium (Ca) reduces interfacial reactivity, decreasing excessive reaction at the magnesium-aluminum interface, inhibiting the formation of brittle phases, and significantly improving the stability of the bonding interface. The addition of beryllium (Be) improves the oxidation resistance and heat resistance of the magnesium alloy, effectively reducing oxide formation during high-temperature processing and further inhibiting the formation of undesirable interfacial phases. Tin (Sn) improves the plasticity and fluidity of the magnesium alloy, resulting in a more uniform stress distribution during rolling, reducing stress concentration-induced cracks, and ensuring the quality and stability of the interfacial bonding.

[0025] Furthermore, this invention employs an asynchronous rolling process, adjusting the roll speed difference between the aluminum alloy layer and the magnesium alloy layer to generate shear strain, thereby promoting metallurgical bonding between the aluminum and magnesium layers. Shear strain introduces transverse plastic flow at the interface, increasing deformation compatibility and reducing interlayer slippage and stress concentration, thus effectively improving interfacial bonding strength. On the other hand, the high reduction rate in the initial pass is beneficial for the plastic deformation of the magnesium alloy layer, enabling more thorough alteration of its microstructure and promoting a tighter bond between it and the aluminum alloy layer at the interface. Through the high deformation during asynchronous rolling, the interfacial reaction proceeds more uniformly, reducing the formation of brittle and hard intermetallic compounds (such as Al3Mg2). This interfacial bonding achieved through plastic flow and strain regulation ensures that the composite material effectively weakens the formation of brittle phases while improving bonding strength, thus enhancing the material's toughness and corrosion resistance. This invention, through precise alloy composition design and optimized rolling process, effectively solves the problems of insufficient interfacial bonding strength and the easy formation of brittle and hard second phases in aluminum-magnesium composite materials. Detailed Implementation

[0026] This invention provides a high-strength, tough, and corrosion-resistant aluminum-magnesium composite plate, which includes a first aluminum alloy layer, a magnesium alloy layer, and a second aluminum alloy layer stacked sequentially.

[0027] The first aluminum alloy layer and the second aluminum alloy layer independently contain the following components by mass fraction: Mg 3.0–5.5%, Mn 0.3–1.2%, Si 0.1–0.4%, Fe 0.15–0.4%, Cu 0.05–0.75%, Sc 0.1–0.3%, and Al balance;

[0028] The magnesium alloy layer contains the following components by mass fraction: Al 2.0–4.0%, Ca 1.5–4.0%, Mn 0.2–1.0%, Be 0.1–0.5%, Sn 0.5–2.0%, and Mg balance.

[0029] In this invention, scandium (Sc) and copper (Cu) elements in the first and second aluminum alloy layers effectively promote the metallurgical bonding of the aluminum-magnesium layers and enhance the bonding strength during the rolling process of the aluminum-magnesium composite sheet by refining the grains and improving high-temperature stability. Scandium (Sc) refines the grains, reduces interfacial stress concentration and the formation of brittle intermetallic compounds, while manganese (Mn) inhibits the precipitation of brittle and hard phases by forming stabilizing compounds. The rational combination of these elements effectively weakens the formation of brittle and hard phases, ensuring that the composite sheet possesses excellent mechanical properties and corrosion resistance.

[0030] In this invention, in the magnesium alloy layer, calcium (Ca) reduces the formation of brittle phases by lowering interfacial reactivity, beryllium (Be) enhances the oxidation resistance of the magnesium alloy and stabilizes the interfacial bonding, while tin (Sn) improves plasticity, reduces stress concentration, enhances the plastic forming properties of the magnesium alloy, and inhibits the formation of brittle and hard phases at the interface. This rational combination of elements ensures that the composite material possesses high bonding strength and good mechanical properties.

[0031] In this invention, preferably, the first aluminum alloy layer and the second aluminum alloy layer independently contain the following components by mass fraction: Mg 3.5-5.0%, Mn 0.5-1.0%, Si 0.15-0.35%, Fe 0.2-0.35%, Cu 0.10-0.65%, Sc 0.15-0.25%, and Al balance.

[0032] In this invention, more preferably, the first aluminum alloy layer and the second aluminum alloy layer independently contain the following components by mass fraction: Mg 4.0-4.5%, Mn 0.6-0.9%, Si 0.2-0.3%, Fe 0.25-0.3%, Cu 0.20-0.55%, Sc 0.17-0.23%, and Al balance.

[0033] In this invention, more preferably, the first aluminum alloy layer and the second aluminum alloy layer independently contain the following components by mass fraction: Mg 4.2-4.3%, Mn 0.7-0.8%, Si 0.25%, Fe 0.26-0.28%, Cu 0.30-0.40%, Sc 0.2%, and Al balance.

[0034] In this invention, preferably, the magnesium alloy layer comprises the following components by mass fraction: Al 2.5-3.5%, Ca 2.0-3.5%, Mn 0.4-0.8%, Be 0.2-0.4%, Sn 0.7-1.8%, and Mg balance.

[0035] In this invention, more preferably, the magnesium alloy layer comprises the following components by mass fraction: Al 2.7-3.3%, Ca 2.5-3.0%, Mn 0.5-0.7%, Be 0.25-0.35%, Sn 1-1.5%, and Mg balance.

[0036] In this invention, more preferably, the magnesium alloy layer comprises the following components by mass fraction: Al 3.0%, Ca 2.6-2.8%, Mn 0.6%, Be 0.3%, Sn 1.2-1.3%, and Mg balance.

[0037] The present invention also provides a method for preparing the high-strength, tough, and corrosion-resistant aluminum-magnesium composite plate, comprising the following steps:

[0038] (1) Mix the components contained in the first aluminum alloy layer and perform a first smelting to obtain a first aluminum alloy; mix the components contained in the second aluminum alloy layer and perform a second smelting to obtain a second aluminum alloy; mix the components contained in the magnesium alloy layer under a protective atmosphere and perform a third smelting to obtain a magnesium alloy.

[0039] (2) The first aluminum alloy is subjected to a first solution treatment to obtain a first aluminum alloy layer; the second aluminum alloy is subjected to a second solution treatment to obtain a second aluminum alloy layer; the magnesium alloy is subjected to a third solution treatment to obtain a magnesium alloy layer.

[0040] (3) The first aluminum alloy layer, the magnesium alloy layer and the second aluminum alloy layer are stacked in sequence. After the stacking is completed, rolling and heat treatment are performed in sequence to obtain the high-strength, tough and corrosion-resistant aluminum-magnesium composite plate.

[0041] In this invention, the preferred process of mixing the components of the first aluminum alloy layer and performing the first smelting in step (1) is as follows: First, pure metal Al is added. After Al is completely melted, Mg, Cu, Mn, Si, and Sc are added. Mg is added in the form of pure metal Mg or Al-Mg alloy, Cu is added in the form of pure metal Cu or Al-Cu alloy, Mn is added in the form of Al-Mn alloy, Si is added in the form of Al-Si alloy, and Sc is added in the form of Al-Sc alloy. After all raw materials are melted, the first smelting is completed. During the feeding and first smelting process, sufficient stirring is maintained to ensure the uniformity of the alloy composition. The order and amount of each raw material added are determined by those skilled in the art based on the composition of the first aluminum alloy through conventional selection. After the first smelting is completed, it is cast and naturally cooled to room temperature to obtain the first aluminum alloy. The Fe in the final first aluminum alloy comes from pure metal Al and Al in the intermediate alloy.

[0042] In this invention, in step (1), the preparation process of the second aluminum alloy is the same as that of the first aluminum alloy.

[0043] In this invention, in step (1), the protective atmosphere is preferably a mixed atmosphere of CO2 and SF6 or an argon atmosphere; the volume ratio of CO2 to SF6 in the mixed atmosphere is preferably 95-105:1, more preferably 97-103:1, and even more preferably 100:1; the purpose of setting the protective atmosphere is to prevent the magnesium melt from oxidizing and burning during the smelting process; the process of mixing the components contained in the magnesium alloy layer and carrying out the third smelting is preferably as follows: first, pure metal Mg is added, and after Mg is completely melted, pure metals Al, Al-Ca alloy, and A are added. The magnesium alloy is prepared by melting 1-Mn alloy, Al-Be alloy, and pure Sn. After all raw materials are melted, a third smelting process is completed. Sufficient stirring is maintained during the feeding and third smelting process to ensure the uniformity of the alloy composition. The order and amount of each raw material added are determined by those skilled in the art based on the composition of the magnesium alloy through conventional selection. After the third smelting is completed, the alloy is cast and naturally cooled to room temperature to obtain the magnesium alloy. During the preparation of the magnesium alloy, the Al content is low, and correspondingly, the amount of aluminum raw material added is low, so the Fe content in the final magnesium alloy is negligible.

[0044] In this invention, the temperatures of the first and second melting processes in step (1) are preferably 700-770°C, more preferably 710-740°C, and even more preferably 720-730°C; the temperature of the third melting process is preferably 680-750°C, more preferably 690-720°C, and even more preferably 700-710°C.

[0045] In this invention, the temperatures of the first solution treatment and the second solution treatment in step (2) are preferably 500-550°C, more preferably 510-540°C, and even more preferably 520-530°C; the times of the first solution treatment and the second solution treatment are preferably 2-12 hours, more preferably 4-10 hours, and even more preferably 6-8 hours.

[0046] In this invention, the temperature of the third solution treatment is preferably 450-500°C, more preferably 460-490°C, and even more preferably 470-480°C; the time of the third solution treatment is preferably 4-24 hours, more preferably 10-20 hours, and even more preferably 12-16 hours.

[0047] In this invention, the purpose of the first solution treatment and the second solution treatment in step (2) is to improve the plasticity and corrosion resistance of the alloy and enhance the forming performance of subsequent rolling; the purpose of the third solution treatment is to refine the grains and enhance the corrosion resistance and strength of the magnesium alloy; after step (2) is completed, the first aluminum alloy layer, the magnesium alloy layer and the second aluminum alloy layer are cleaned independently, dried after cleaning, and then step (3) is performed.

[0048] In this invention, the cleaning is performed using conventional techniques in the art. The cleaning method preferably includes sequential mechanical grinding, chemical cleaning, and water washing. When the object to be cleaned is the first aluminum alloy layer or the second aluminum alloy layer, the chemical cleaning reagent is preferably a mixed solution of phosphoric acid and nitric acid, hydrofluoric acid solution, or sodium hydroxide solution. When the object to be cleaned is the magnesium alloy layer, the chemical cleaning reagent is preferably a mixed solution of chromic acid and nitric acid, hydrofluoric acid solution, trisodium phosphate solution, or sodium carbonate solution. The mass fraction of each reagent is determined using conventional techniques in the art. The purpose of the cleaning is to remove the oxide layer and impurities, ensure the cleanliness of the alloy layer bonding surface, and improve the bonding effect in the subsequent rolling process.

[0049] In this invention, the thickness of the first aluminum alloy layer and the second aluminum alloy layer in step (3) is preferably 4-8 mm, more preferably 5-7 mm, and even more preferably 6 mm; the thickness of the magnesium alloy layer is preferably 6-10 mm, more preferably 7-9 mm, and even more preferably 8 mm.

[0050] In this invention, during step (3), the transverse length of the first aluminum alloy layer and the second aluminum alloy layer is preferably greater than the transverse length of the magnesium alloy layer, so as to achieve a better interlocking effect in the subsequent rolling process.

[0051] In this invention, the number of rolling passes in step (3) is preferably ≥2, more preferably ≥3, and more preferably ≥4; the total reduction rate of rolling (the reduction rate is calculated by subtracting the thickness of the composite plate after rolling from the initial thickness of the composite plate and dividing by the initial thickness of the composite plate) is preferably 50-85%, more preferably 65-80%, and more preferably 70-75%.

[0052] In this invention, the first pass is a high-strain rolling process, and the rolling reduction rate of the first pass is preferably 50-75%, more preferably 55-70%, and even more preferably 60-65%; the rolling temperature of the first pass is preferably 400-480°C, more preferably 420-460°C, and even more preferably 430-450°C; the rolling reduction rate of the remaining passes is independently preferably 10-15%, more preferably 11-14%, and even more preferably 12-13%; the rolling temperature of the remaining passes is independently preferably 400-490°C, more preferably 420-470°C, and even more preferably 430-460°C; the rolling temperature of the remaining passes is preferably ≥ the rolling temperature of the first pass.

[0053] In this invention, the large reduction rate in the first pass is beneficial to the plastic deformation of the difficult-to-deform magnesium alloy layer in the middle, and can promote interfacial bonding during the plastic deformation process; through the specific rolling process of this invention, good metallurgical bonding can be ensured and the formation of brittle phases can be reduced.

[0054] In this invention, the speed of the upper rolling roll in step (3) is preferably 5-10 m / min, more preferably 6-9 m / min, and even more preferably 7-8 m / min; the speed of the lower rolling roll is preferably 3-8 m / min, more preferably 4-7 m / min, and even more preferably 5-6 m / min; the asynchronous ratio of rolling is preferably 1.2-1.9, more preferably 1.3-1.8, and even more preferably 1.6-1.75; the asynchronous rolling process is adopted in step (3), and the speeds of the upper and lower rolling rolls are different, which increases the shear strain between the aluminum-magnesium layers, promotes the metallurgical bonding of the two layers, reduces the plastic deformation resistance of the magnesium alloy layer, and improves the forming ability of the magnesium alloy layer.

[0055] In this invention, the heat treatment temperature in step (3) is preferably 200-300°C, more preferably 230-280°C, and even more preferably 250-260°C; the heat treatment time is preferably 0.5-2h, more preferably 1-1.5h, and even more preferably 1.2-1.3h; the purpose of the heat treatment is to reduce the residual stress generated during the rolling process and to optimize the interfacial metallurgical bonding strength, corrosion resistance, and mechanical properties of the composite material.

[0056] This invention also provides the application of the high-strength, tough, and corrosion-resistant aluminum-magnesium composite sheet in aerospace, automobile manufacturing, or marine engineering.

[0057] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0058] Example 1

[0059] In this embodiment, the first aluminum alloy layer contains the following components by mass fraction: Mg 4.0%, Mn 0.6%, Si 0.3%, Fe 0.2%, Cu 0.2%, Sc 0.2%, and Al balance; the second aluminum alloy layer has the same composition as the first aluminum alloy layer; the magnesium alloy layer contains the following components by mass fraction: Al 3.0%, Ca 3.0%, Mn 0.5%, Be 0.3%, Sn 1.5%, and Mg balance.

[0060] The components of the first aluminum alloy layer are mixed and subjected to a first smelting process. Specifically, pure metallic Al is first added, and after the Al is completely melted, Al-Mg alloy, Al-Cu alloy, Al-Mn alloy, Al-Si alloy, and Al-Sc alloy are added sequentially (the type of each alloy is not required, as long as it meets the requirements for the composition content in the final aluminum alloy layer). After all raw materials are melted, the first smelting is completed. The temperature of the first smelting is set at 700℃. During the addition of materials and the first smelting process, thorough stirring is maintained to ensure the uniformity of the alloy composition. After the first smelting is completed, the mixture is poured and allowed to cool naturally to room temperature to obtain the first aluminum alloy (the Fe in the first aluminum alloy comes from pure metallic Al and intermediate alloys). The second aluminum alloy was prepared using the same preparation method as the first aluminum alloy. Under an argon atmosphere, the components of the magnesium alloy layer were mixed and subjected to a third smelting. Specifically, first, pure metal Mg was added. After Mg was completely melted, pure metal Al, Al-Ca alloy, Al-Mn alloy, Al-Be alloy, and pure metal Sn were added in sequence (the type of each alloy is not required, as long as it meets the requirements of the component content in the final magnesium alloy layer). After all the raw materials were melted, the third smelting was completed. The temperature of the third smelting was set at 700℃. During the addition of materials and the third smelting process, the mixture was stirred thoroughly to ensure the uniformity of the alloy composition. After the third smelting was completed, the mixture was cast and allowed to cool naturally to room temperature to obtain the magnesium alloy.

[0061] The first aluminum alloy layer was obtained by solution treatment at 520℃ for 6 hours. The second aluminum alloy layer was prepared using the same method. The magnesium alloy layer was obtained by solution treatment at 480℃ for 12 hours. The first, magnesium, and second aluminum alloy layers were then independently and sequentially subjected to mechanical polishing, chemical cleaning, and water washing. The chemical cleaning reagent for the first and second aluminum alloy layers was a 2% hydrofluoric acid solution, while the chemical cleaning reagent for the magnesium alloy was a 0.5% hydrofluoric acid solution. After water washing, the layers were dried. The layers are stacked sequentially, with the first and second aluminum alloy layers both 6mm thick, and the magnesium alloy layer 8mm thick. The transverse lengths of the first and second aluminum alloy layers are greater than the transverse length of the magnesium alloy layer. After stacking, rolling is performed under the following conditions: two passes, a total reduction rate of 69.2%, a first pass reduction rate of 65%, a first pass rolling temperature of 450℃, a remaining pass (i.e., the second pass) reduction rate of 12%, and a remaining pass rolling temperature of 460℃; the upper roll speed is 8m / min, the lower roll speed is 5m / min, and the asynchronous ratio is 1.6. Finally, the material is heat-treated at 250℃ for 1 hour to obtain a high-strength, tough, and corrosion-resistant aluminum-magnesium composite plate.

[0062] The high-strength, tough, and corrosion-resistant aluminum-magnesium composite plate prepared in this embodiment was subjected to performance tests (mechanical property tests were conducted according to standard GB / T228.1, and exfoliation corrosion tests were conducted according to standard GB / T22639). The results showed that the high-strength, tough, and corrosion-resistant aluminum-magnesium composite plate in this embodiment had a tensile strength of 370 MPa, a yield strength of 340 MPa, an elongation of 16%, and an exfoliation corrosion level of N.

[0063] Example 2

[0064] In this embodiment, the first aluminum alloy layer contains the following components by mass fraction: Mg 3.5%, Mn 0.5%, Si 0.2%, Fe 0.2%, Cu 0.1%, Sc 0.15%, and Al balance; the second aluminum alloy layer has the same composition as the first aluminum alloy layer; the magnesium alloy layer contains the following components by mass fraction: Al 2.5%, Ca 2.0%, Mn 0.4%, Be 0.2%, Sn 1.2%, and Mg balance.

[0065] The components of the first aluminum alloy layer are mixed and subjected to a first smelting process. Specifically, pure metallic Al is first added, and after the Al is completely melted, Al-Mg alloy, Al-Cu alloy, Al-Mn alloy, Al-Si alloy, and Al-Sc alloy are added sequentially (the type of each alloy is not required, as long as it meets the requirements for the composition content in the final aluminum alloy layer). After all raw materials are melted, the first smelting is completed. The temperature of the first smelting is set at 700℃. During the addition of materials and the first smelting process, thorough stirring is maintained to ensure the uniformity of the alloy composition. After the first smelting is completed, the mixture is poured and allowed to cool naturally to room temperature to obtain the first aluminum alloy (the Fe in the first aluminum alloy comes from pure metallic Al and intermediate alloys). The second aluminum alloy was prepared using the same preparation method as the first aluminum alloy. Under an argon atmosphere, the components of the magnesium alloy layer were mixed and subjected to a third smelting. Specifically, first, pure metal Mg was added. After Mg was completely melted, pure metal Al, Al-Ca alloy, Al-Mn alloy, Al-Be alloy, and pure metal Sn were added in sequence (the type of each alloy is not required, as long as it meets the requirements of the component content in the final magnesium alloy layer). After all the raw materials were melted, the third smelting was completed. The temperature of the third smelting was set at 700℃. During the addition of materials and the third smelting process, the mixture was stirred thoroughly to ensure the uniformity of the alloy composition. After the third smelting was completed, the mixture was cast and allowed to cool naturally to room temperature to obtain the magnesium alloy.

[0066] The first aluminum alloy layer was obtained by solution treatment at 510℃ for 4 hours. The second aluminum alloy layer was prepared using the same method. The magnesium alloy layer was obtained by solution treatment at 460℃ for 10 hours. The first, magnesium, and second aluminum alloy layers were then independently and sequentially subjected to mechanical polishing, chemical cleaning, and water washing. The chemical cleaning reagent for the first and second aluminum alloy layers was an 8% sodium hydroxide solution, while the chemical cleaning reagent for the magnesium alloy was a 6% sodium carbonate solution. After water washing, the layers were dried, and then the first, magnesium, and second aluminum alloy layers were processed sequentially. The layers are stacked sequentially, with the first and second aluminum alloy layers both 5mm thick, and the magnesium alloy layer 7mm thick. The transverse lengths of the first and second aluminum alloy layers are greater than the transverse length of the magnesium alloy layer. After stacking, rolling is performed under the following conditions: two passes, a total reduction rate of 64.8%, a first pass reduction rate of 60%, a first pass rolling temperature of 430℃, and the remaining passes (i.e., the second pass) with a reduction rate of 12% and a remaining pass rolling temperature of 430℃. The upper roll speed is 7m / min, the lower roll speed is 4m / min, and the asynchronous ratio is 1.75. Finally, the material is heat-treated at 230℃ for 1.5h to obtain a high-strength, tough, and corrosion-resistant aluminum-magnesium composite plate.

[0067] Using the same testing method as in Example 1, the performance of the high-strength, tough, and corrosion-resistant aluminum-magnesium composite plate prepared in this example was tested. The results showed that the tensile strength of the high-strength, tough, and corrosion-resistant aluminum-magnesium composite plate in this example was 360 MPa, the yield strength was 330 MPa, the elongation was 18%, and the peeling corrosion level was N.

[0068] Example 3

[0069] In this embodiment, the first aluminum alloy layer contains the following components by mass fraction: Mg 5.0%, Mn 0.8%, Si 0.4%, Fe 0.3%, Cu 0.4%, Sc 0.25%, and Al balance; the second aluminum alloy layer has the same composition as the first aluminum alloy layer; the magnesium alloy layer contains the following components by mass fraction: Al 4.0%, Ca 3.5%, Mn 0.6%, Be 0.5%, Sn 2.0%, and Mg balance.

[0070] The components of the first aluminum alloy layer are mixed and subjected to a first smelting process. Specifically, pure metallic Al is first added, and after the Al is completely melted, Al-Mg alloy, Al-Cu alloy, Al-Mn alloy, Al-Si alloy, and Al-Sc alloy are added sequentially (the type of each alloy is not required, as long as it meets the requirements for the composition content in the final aluminum alloy layer). After all raw materials are melted, the first smelting is completed. The temperature of the first smelting is set at 700℃. During the addition of materials and the first smelting process, thorough stirring is maintained to ensure the uniformity of the alloy composition. After the first smelting is completed, the mixture is poured and allowed to cool naturally to room temperature to obtain the first aluminum alloy (the Fe in the first aluminum alloy comes from pure metallic Al and intermediate alloys). The second aluminum alloy was prepared using the same preparation method as the first aluminum alloy. Under an argon atmosphere, the components of the magnesium alloy layer were mixed and subjected to a third smelting. Specifically, first, pure metal Mg was added. After Mg was completely melted, pure metal Al, Al-Ca alloy, Al-Mn alloy, Al-Be alloy, and pure metal Sn were added in sequence (the type of each alloy is not required, as long as it meets the requirements of the component content in the final magnesium alloy layer). After all the raw materials were melted, the third smelting was completed. The temperature of the third smelting was set at 700℃. During the addition of materials and the third smelting process, the mixture was stirred thoroughly to ensure the uniformity of the alloy composition. After the third smelting was completed, the mixture was cast and allowed to cool naturally to room temperature to obtain the magnesium alloy.

[0071] The first aluminum alloy was solution treated at 530℃ for 8 hours to obtain the first aluminum alloy layer. The second aluminum alloy layer was prepared using the same method. The magnesium alloy was solution treated at 490℃ for 16 hours to obtain the magnesium alloy layer. The first, magnesium, and second aluminum alloy layers were then independently and sequentially subjected to mechanical polishing, chemical cleaning, and water washing. The chemical cleaning reagent for the first and second aluminum alloy layers was a mixed solution of phosphoric acid and nitric acid, with a phosphoric acid mass fraction of 15% and a nitric acid mass fraction of 3%. The chemical cleaning reagent for the magnesium alloy was a mixed solution of chromic acid and nitric acid, with a chromic acid mass fraction of 4% and a nitric acid mass fraction of 1.5%. After water washing, the layers were dried... The material is dried, and then laminated in the order of first aluminum alloy layer, magnesium alloy layer and second aluminum alloy layer. The thickness of the first and second aluminum alloy layers is 7 mm, the thickness of the magnesium alloy layer is 9 mm, and the lateral length of the first and second aluminum alloy layers is greater than the lateral length of the magnesium alloy layer. After lamination, rolling is performed. The rolling conditions are set as follows: 2 passes, total reduction rate of 73.9%, rolling reduction rate of 70% in the first pass, rolling temperature of 460℃ in the first pass, rolling reduction rate of 13% in the remaining passes (i.e., the second pass), rolling temperature of 470℃ in the remaining passes, upper roll speed of 10 m / min, lower roll speed of 6 m / min, asynchronous ratio of 1.67, and finally heat-treated at 260℃ for 1 h to obtain high-strength, tough and corrosion-resistant aluminum-magnesium composite plate.

[0072] Using the same testing method as in Example 1, the performance of the high-strength, tough, and corrosion-resistant aluminum-magnesium composite plate prepared in this example was tested. The results showed that the tensile strength of the high-strength, tough, and corrosion-resistant aluminum-magnesium composite plate in this example was 390 MPa, the yield strength was 360 MPa, the elongation was 14%, and the exfoliation corrosion level was N.

[0073] Comparative Example 1

[0074] In this comparative example, the composition of the first aluminum alloy layer is set according to 5083 aluminum alloy; the composition of the second aluminum alloy layer is the same as that of the first aluminum alloy layer; the magnesium alloy layer contains the following components by mass fraction: Al 3.0%, Ca 2.5%, Mn 0.3%, and Mg balance.

[0075] The components of the first aluminum alloy layer are mixed and subjected to a first melting process at a temperature of 710°C. After the first melting process is completed, the mixture is poured and allowed to cool naturally to room temperature to obtain the first aluminum alloy. The second aluminum alloy is prepared using the same preparation method as the first aluminum alloy. Under an argon atmosphere, the components of the magnesium alloy layer are mixed and subjected to a third melting process at a temperature of 700°C. After the third melting process is completed, the mixture is poured and allowed to cool naturally to room temperature to obtain the magnesium alloy.

[0076] The first aluminum alloy was solution treated at 500℃ for 4 hours to obtain the first aluminum alloy layer. The second aluminum alloy layer was prepared using the same method. The magnesium alloy was solution treated at 450℃ for 6 hours to obtain the magnesium alloy layer. The first aluminum alloy layer, the magnesium alloy layer, and the second aluminum alloy layer were then independently and sequentially subjected to mechanical polishing, chemical cleaning, and water washing. The chemical cleaning reagent for the first and second aluminum alloy layers was a 2% hydrofluoric acid solution; the chemical cleaning reagent for the magnesium alloy was a 0.5% hydrofluoric acid solution. After washing, the material is dried and then laminated in the order of first aluminum alloy layer, magnesium alloy layer, and second aluminum alloy layer. The thickness of the first and second aluminum alloy layers is 5 mm, and the thickness of the magnesium alloy layer is 7 mm. The transverse length of the first and second aluminum alloy layers is greater than the transverse length of the magnesium alloy layer. After lamination, the material is rolled. The rolling conditions are set as follows: single-pass reduction rate is about 15%, total rolling reduction rate is 60%, rolling temperature is 400℃, upper roll speed is 5 m / min, lower roll speed is 5 m / min, and finally, the material is heat-treated at 200℃ for 1 hour to obtain the composite plate.

[0077] Using the same testing method as in Example 1, the composite board prepared in this comparative example was subjected to performance testing. The results showed that the tensile strength of the composite board in this comparative example was 240 MPa, the yield strength was 200 MPa, the elongation was 8%, and the peeling corrosion level was PB.

[0078] As can be seen from the above examples and comparative examples, the high-strength, high-toughness, and corrosion-resistant aluminum-magnesium composite plates prepared in Examples 1-3 have tensile strengths between 360 and 390 MPa and yield strengths between 330 and 360 MPa, significantly higher than the 240 MPa and 200 MPa of the comparative examples. The elongation of the high-strength, high-toughness, and corrosion-resistant aluminum-magnesium composite plates prepared in Examples 1-3 is between 14 and 18%, better than the 8% of the comparative examples. This indicates that the mechanical properties of the composite plates are significantly improved by optimizing the alloy composition design and adopting an asynchronous rolling process.

[0079] According to the exfoliation corrosion test standard GB / T22639, the high-strength, tough, and corrosion-resistant aluminum-magnesium composite plates prepared in Examples 1-3 all exhibited an exfoliation corrosion rating of N, indicating excellent corrosion resistance. In contrast, Comparative Example 1 showed an exfoliation corrosion rating of PB, indicating poor corrosion resistance.

[0080] As can be seen, the high-strength, tough, and corrosion-resistant aluminum-magnesium composite plates prepared in Examples 1-3 are significantly superior to the composite plate prepared in Comparative Example 1 in both mechanical properties and corrosion resistance. This is mainly attributed to the addition of elements such as scandium (Sc) and copper (Cu) in the aluminum alloy composition, and calcium (Ca), tin (Sn), and beryllium (Be) in the magnesium alloy composition. These elements improve the overall performance of the composite material by refining the grains and enhancing the high-temperature stability and corrosion resistance of the alloy. Simultaneously, the asynchronous rolling process introduces shear strain between the aluminum and magnesium alloy layers, enhancing the interfacial bonding strength, effectively reducing the formation of brittle intermetallic compounds, and improving the overall performance of the material.

[0081] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A high-strength, tough, and corrosion-resistant aluminum-magnesium composite sheet, characterized in that, The high-strength, tough, and corrosion-resistant aluminum-magnesium composite plate comprises a first aluminum alloy layer, a magnesium alloy layer, and a second aluminum alloy layer stacked sequentially. The first aluminum alloy layer and the second aluminum alloy layer independently contain the following components by mass fraction: Mg 3.0–5.5%, Mn 0.3–1.2%, Si 0.1–0.4%, Fe 0.15–0.4%, Cu 0.05–0.75%, Sc 0.1–0.3%, and Al balance; The magnesium alloy layer contains the following components by mass fraction: Al 2.0–4.0%, Ca 1.5–4.0%, Mn 0.2–1.0%, Be 0.1–0.5%, Sn 0.5–2.0%, and Mg balance.

2. The method for preparing the high-strength, tough, and corrosion-resistant aluminum-magnesium composite plate according to claim 1, characterized in that, Includes the following steps: (1) Mix the components contained in the first aluminum alloy layer and perform a first smelting to obtain a first aluminum alloy; mix the components contained in the second aluminum alloy layer and perform a second smelting to obtain a second aluminum alloy; mix the components contained in the magnesium alloy layer under a protective atmosphere and perform a third smelting to obtain a magnesium alloy. (2) The first aluminum alloy is subjected to a first solution treatment to obtain a first aluminum alloy layer; the second aluminum alloy is subjected to a second solution treatment to obtain a second aluminum alloy layer; the magnesium alloy is subjected to a third solution treatment to obtain a magnesium alloy layer. (3) The first aluminum alloy layer, the magnesium alloy layer and the second aluminum alloy layer are stacked in sequence. After the stacking is completed, rolling and heat treatment are performed in sequence to obtain the high-strength, tough and corrosion-resistant aluminum-magnesium composite plate.

3. The method for preparing the high-strength, tough, and corrosion-resistant aluminum-magnesium composite plate as described in claim 2, characterized in that, In step (1), the temperatures of the first and second melting processes are independently 700–770°C, and the temperature of the third melting process is 680–750°C.

4. The method for preparing the high-strength, tough, and corrosion-resistant aluminum-magnesium composite plate as described in claim 3, characterized in that, In step (2), the temperature of the first solution treatment and the second solution treatment are independently 500-550℃, and the time of the first solution treatment and the second solution treatment is independently 2-12h; The temperature of the third solution treatment is 450–500℃, and the time of the third solution treatment is 4–24 hours.

5. The method for preparing the high-strength, tough, and corrosion-resistant aluminum-magnesium composite plate as described in claim 4, characterized in that, In step (3), the thickness of the first aluminum alloy layer and the second aluminum alloy layer are 4 to 8 mm, and the thickness of the magnesium alloy layer is 6 to 10 mm.

6. The method for preparing high-strength, tough, and corrosion-resistant aluminum-magnesium composite plates as described in claim 2 or 5, characterized in that, In step (3), the number of rolling passes is ≥2; the total rolling reduction is 50-85%; The rolling reduction rate of the first pass is 50-75%, and the rolling temperature of the first pass is 400-480℃; the rolling reduction rate of the remaining passes is independently 10-15%, and the rolling temperature of the remaining passes is independently 400-490℃; the rolling temperature of the remaining passes is ≥ the rolling temperature of the first pass.

7. The method for preparing the high-strength, tough, and corrosion-resistant aluminum-magnesium composite plate as described in claim 6, characterized in that, In step (3), the upper rolling roll rotates at a speed of 5 to 10 m / min, the lower rolling roll rotates at a speed of 3 to 8 m / min, and the asynchronous ratio of the rolling is 1.2 to 1.

6.

8. The method for preparing the high-strength, tough, and corrosion-resistant aluminum-magnesium composite plate as described in claim 7, characterized in that, The heat treatment temperature in step (3) is 200-300℃ and the heat treatment time is 0.5-2h.

9. The application of the high-strength, tough, and corrosion-resistant aluminum-magnesium composite sheet as described in claim 1 in aerospace, automobile manufacturing, or marine engineering.