High-corrosion-resistance aluminum alloy material and preparation method thereof

Abstract

The invention discloses a high-corrosion-resistance aluminum alloy material and a preparation method thereof, and belongs to the technical field of non-ferrous metal material processing, by adding trace alloying elements Mn, Cr, Mo, Sc, Zr, Yb, Hf, Er, Nb and Ni into an aluminum alloy, a multi-scale dispersed phase is formed, a microstructure is optimized, distribution of Cu at a grain boundary is regulated and controlled, grain boundary segregation of the Cu element is inhibited, and meanwhile, the corrosion resistance of the aluminum alloy material is improved. The added alloy elements can form stable oxides on the surface of the alloy, the stability and compactness of a passivation film on the surface of the aluminum alloy are enhanced, the corrosion resistance of the alloy is improved, the corrosion resistance of the Cu-containing aluminum alloy can be remarkably improved through the method, the maximum corrosion depth of the Cu-containing aluminum alloy is reduced by about 50%, the corrosion resistance grade is improved to the grade IV, and the service life of the Cu-containing aluminum alloy is prolonged. Through combination of alloy component optimization and heat treatment regulation, a new technical approach is provided for design and preparation of the high-strength and high-corrosion-resistance aluminum alloy.

Description

Technical Field

[0001] This application relates to the field of non-ferrous metal material processing, specifically to a high corrosion-resistant aluminum alloy material and its preparation method. Background Technology

[0002] Aluminum alloys are widely used in aerospace, transportation, shipbuilding, and construction due to their low density, high specific strength, and ease of processing and forming. However, in actual service environments, aluminum alloys often face various complex conditions, such as high humidity, air pollution, and marine environments. These factors can lead to corrosion damage, affecting their structural stability and service life. Therefore, while ensuring high strength, improving the corrosion resistance of aluminum alloys is crucial for ensuring their long-term stable service.

[0003] In aluminum alloy systems, copper (Cu) is a key strengthening element. The addition of Cu can significantly improve the mechanical properties of the alloy; for example, Al-Cu, Al-Si-Cu, Al-Mg-Si-Cu, and Al-Zn-Mg-Cu alloys all exhibit high strength. However, the addition of Cu leads to a significant decrease in the corrosion resistance of aluminum alloys, mainly in the following aspects: First, the presence of Cu reduces the density of the passivation film on the aluminum alloy surface, making the alloy more susceptible to corrosion. Second, Cu readily forms coarse intermetallic compounds in aluminum alloys, thereby increasing the alloy's pitting corrosion tendency. Finally, Cu readily segregates at the alloy grain boundaries, forming Cu-rich films and continuous Cu-containing precipitates, thus significantly increasing the alloy's susceptibility to intergranular corrosion. Therefore, improving the corrosion resistance of Cu-containing aluminum alloys has become a major challenge in the development of high-strength, high-corrosion-resistant alloys.

[0004] To address the critical challenge of significantly reduced corrosion resistance in aluminum alloys due to Cu addition, current improvement methods primarily involve optimizing heat treatment processes and controlling grain structure. For example, re-aging and over-aging heat treatments are used to regulate the distribution characteristics of the grain boundary second phase, making it discontinuous and increasing the spacing between these phases to disrupt continuous corrosion paths and improve corrosion resistance. However, these heat treatment methods often lead to coarsening of the grain boundary second phase, increasing the alloy's pitting corrosion tendency and reducing its fracture toughness. On the other hand, while controlling grain boundary structure and increasing the proportion of small-angle grain boundaries to hinder corrosion propagation improves corrosion resistance to some extent, it fails to fundamentally solve the core problem of Cu segregation at grain boundaries. Therefore, a new method is urgently needed to fundamentally improve the corrosion resistance of aluminum alloys by improving the internal microstructure, regulating the distribution of Cu in the matrix, and suppressing Cu grain boundary segregation. Summary of the Invention

[0005] Technical problems solved: This invention provides a high corrosion-resistant aluminum alloy material and its preparation method, solving the problems existing in the prior art, such as the presence of Cu element reducing the density of the passivation film on the aluminum alloy surface, making the alloy more susceptible to corrosion; Cu easily forms coarse intermetallic compounds in aluminum alloys, thereby increasing the alloy's pitting corrosion tendency; Cu element easily segregates at the alloy grain boundaries, forming Cu-rich films and continuous Cu-containing precipitates, thus significantly increasing the alloy's intergranular corrosion sensitivity; heat treatment methods often lead to coarsening of the second phase at the grain boundaries, which not only increases the alloy's pitting corrosion tendency but also reduces the alloy's fracture toughness, failing to fundamentally solve the technical problems such as Cu element segregation at grain boundaries.

[0006] Technical Solution: A high corrosion-resistant aluminum alloy material, wherein the high corrosion-resistant aluminum alloy material is a Cu-containing high corrosion-resistant aluminum alloy material, specifically one of the Al-Cu-Mg system, Al-Si-Cu system, Al-Mg-Si-Cu system, and Al-Zn-Mg-Cu system alloys. The chemical composition of the Cu-containing high corrosion-resistant aluminum alloy material, by weight percentage, includes the following microalloying elements: Mn: 0.1-1.2 wt.%; Cr: 0.05-0.3 wt.%; Mo: 0.05-0.3 wt.%; Sc: 0.05-0.6 wt.%; Zr: 0.05-0.3 wt.%; Yb: 0.05-0.2 wt.%; Hf: 0.05-0.6 wt.%; Er: 0.05-0.15 wt.%; Nb: 0.05-0.15 wt.%; Ni: 0.05-0.2 wt.%.

[0007] Furthermore, the microalloying elements need to be added in combination, specifically including: the total amount of Mn+Cr composite addition not exceeding 1.5 wt.%, with a Mn:Cr mass ratio of 4:1~2:1; the total amount of Mn+Mo composite addition not exceeding 1.5 wt.%, with a Mn:Mo mass ratio of 4:1~2:1; the total amount of Mn+Zr composite addition not exceeding 1.5 wt.%, with a Mn:Zr mass ratio of 4:1~2:1; the total amount of Mn+Ni composite addition not exceeding 1.4 wt.%, with a Mn:Mo mass ratio of 6:1~2:1; the total amount of Zr+Hf composite addition not exceeding 0.9 wt.%, with a Zr:Hf mass ratio of 1:1~1:2; the total amount of Zr+Sc composite addition not exceeding 0.9 wt.%, with a Zr:Sc mass ratio of 1:1~1:2; and the total amount of Zr+Yb composite addition not exceeding 0.5 wt.%. The total amount of Zr+Er composite addition is not more than 0.45 wt.%, and the Zr:Er mass ratio is 2:1 to 1:1; the total amount of Zr+Nb composite addition is not more than 0.45 wt.%, and the Zr:Nb mass ratio is 2:1 to 1:1; the total amount of Zr+Ni composite addition is not more than 0.5 wt.%, and the Zr:Ni mass ratio is 3:2 to 1:1.

[0008] Furthermore, the microalloying elements need to be added in a ternary composite manner, specifically including: the total amount of Mn+Cr+Mo composite addition not exceeding 1.5 wt.%, with a Mn:Cr:Mo mass ratio of 4:1:1~2:1:1; the total amount of Mn+Cr+Zr composite addition not exceeding 1.8 wt.%, with a Mn:Cr:Zr mass ratio of 4:1:1~2:1:1; the total amount of Mn+Mo+Zr composite addition not exceeding 1.8 wt.%, with a Mn:Mo:Zr mass ratio of 4:1:1~2:1:1; the total amount of Zr+Sc+Hf composite addition not exceeding 1.5 wt.%, with a Zr:Sc:Hf mass ratio of 1:1:1~1:2:2; and the total amount of Zr+Sc+Er ternary composite addition not exceeding 1.05 wt.%, with a Zr:Sc:Er mass ratio of 1:1:1~2:4:1.

[0009] Furthermore, the chemical composition of the Al-Cu-Mg series high corrosion-resistant aluminum alloy material, by weight percentage, includes Cu 3.5-5.0 wt.%, Mg 1.2-1.8 wt.%, with the remainder being Al and unavoidable impurity elements; The chemical composition of the Al-Si-Cu series high corrosion-resistant aluminum alloy material, by weight percentage, includes Cu 1.5-4.0 wt.%, Si 4.5-7.0 wt.%, with the remainder being Al and unavoidable impurity elements; The chemical composition of the Al-Mg-Si-Cu series high corrosion-resistant aluminum alloy material, by weight percentage, includes Cu 0.05-0.6 wt.%, Si 0.4-1.4 wt.%, Mg 0.5-1.2 wt.%, with the remainder being Al and unavoidable impurity elements; The chemical composition of the Al-Zn-Mg-Cu series high corrosion-resistant aluminum alloy material, by weight percentage, includes Cu 1.2-2.0 wt.%, Zn 5.5-7.5 wt.%, Mg 1.5-2.5 wt.%, with the remainder being Al and unavoidable impurity elements.

[0010] This application also discloses a method for preparing any of the above-mentioned high corrosion-resistant aluminum alloy materials, the specific steps of which are as follows: Step 1: Weigh the raw materials according to the weight percentage of the chemical composition. Heat the aluminum in the melting furnace to 760-800℃ to completely melt it, and release the gas and impurities in the aluminum liquid. Add the remaining raw materials in order of melting point from high to low. After the remaining raw materials have completely melted, remove the impurities. Hold the temperature at 700-760℃ for 10-12 minutes and then pour it into the mold for casting. Step 2: Homogenize the alloy ingot with heat treatment, followed by water cooling; Step 3: For Al-Si-Cu alloys, aging treatment is performed directly after homogenization heat treatment; for Al-Cu-Mg, Al-Mg-Si-Cu, and Al-Zn-Mg-Cu alloys, hot deformation, solution treatment, and aging treatment are performed after homogenization heat treatment.

[0011] Furthermore, the homogenization heat treatment includes single-stage and two-stage homogenization heat treatment regimes.

[0012] Furthermore, the single-stage homogenization heat treatment process involves raising the temperature from room temperature to the homogenization heat treatment temperature at a rate of 60-120℃ / h and holding it at that temperature for 12-20h. The homogenization heat treatment temperature is selected according to the alloy type: 460-500℃ for Al-Cu-Mg alloys, 500-550℃ for Al-Si-Cu alloys, 520-560℃ for Al-Mg-Si-Cu alloys, and 470-520℃ for Al-Zn-Mg-Cu alloys.

[0013] Furthermore, the two-stage homogenization heat treatment process includes the following steps: the first-stage heat treatment temperature is 250-350℃, and the temperature is held at this temperature for 6-10 h; then the temperature is increased to the second-stage heat treatment temperature at a rate of 120-300℃ / h and held for 8-14 h; the second-stage heat treatment temperature is selected according to the alloy type: 460-500℃ for Al-Cu-Mg alloy, 500-550℃ for Al-Si-Cu alloy, 520-560℃ for Al-Mg-Si-Cu alloy, and 470-520℃ for Al-Zn-Mg-Cu alloy.

[0014] Furthermore, in the first step, the microalloying elements are all added in the form of master alloys during the smelting process, including Al-10Mn master alloy, Al-10Cr master alloy, Al-5Mo master alloy, Al-2Sc master alloy, Al-5Zr master alloy, Al-4Hf master alloy, Al-5Ni master alloy, Al-2Sc master alloy, Al-10Nb master alloy, and Al-5Yb master alloy. Among the main alloying elements, Cu, Mg, and Zn are added as high-purity metals, and Si is added as Al-20Si master alloy.

[0015] Furthermore, in the first step, the casting temperature is between 680-710 ℃ for Al-Si alloys, and between 700-740 ℃ for Al-Cu-Mg, Al-Mg-Si, and Al-Zn-Mg-Cu alloys.

[0016] Explanation of the principle: 1. Formation of multi-scale nanoscale dispersed phases to optimize microstructure: The addition of microalloying elements such as Mn, Cr, Mo, Zr, Hf, Sc, Yb, Er, Nb, and Ni forms a large number of different types of nanoscale dispersed phases in the matrix, such as Al6M (M=Mn, Mo), Al7Cr, and Al3M (M=Zr, Hf, Sc, Er, Hf, Ni) in Al-Cu and Al-Zn-Mg-Cu systems, and AlFeMSi (M=Mn, Cr, Mo) in Al-Si-Cu and Al-Mg-Si-Cu systems. These dispersed phases can not only refine the grains and increase the grain boundary area, thereby dispersing the segregation of Cu at the grain boundaries, but also adsorb Cu, Zn, Mg, and Si atoms that diffuse relatively quickly in the aluminum matrix, thereby avoiding the excessive segregation of these elements at the grain boundaries. 2. Enhance the stability and density of the passivation film: Alloying elements such as Cr, Zr, and Sc form stable oxides on the alloy surface, enhancing the stability and density of the oxide film, making it difficult for corrosive media to penetrate into the substrate, thereby reducing pitting corrosion and enhancing the corrosion resistance of the alloy.

[0017] Beneficial effects: 1. This application provides a high corrosion-resistant aluminum alloy material. Through the microalloying element addition strategy and deformation heat treatment process optimization of this invention, the microstructure of the alloy is significantly optimized and the corrosion resistance is significantly improved; 2. This application provides a high corrosion-resistant aluminum alloy material and a highly efficient, economical and process-controllable method for improving the corrosion resistance of aluminum alloys, providing important technical support for the high performance and multi-field application of aluminum alloy materials. Attached Figure Description

[0018] Figure 1 This is a diagram showing the segregation distribution characteristics of Mg, Si, and Cu elements at the dispersed phase interface in the Al-Mg-Si-Cu alloy of this application. Detailed Implementation

[0019] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0021] The microstructure analysis of the following examples and comparative samples was evaluated using transmission electron microscopy (TEM) results. The specific implementation methods, operating steps, precautions, and results of this invention are described in detail below with reference to the accompanying drawings. The examples described are only some examples and not all examples.

[0022] Based on Al-Cu-Mg, Al-Si-(Cu), Al-Mg-Si-(Cu), and Al-Zn-Mg-Cu alloys, alloy compositions were designed (see Table 1).

[0023] Table 1 Alloy composition (mass fraction, wt.%) in each embodiment and comparative example

[0024] Example 1: A method for preparing a high corrosion-resistant aluminum alloy material, the specific steps of which are as follows: Step 1: Weigh the raw materials according to the chemical composition in Table 1 by weight percentage. Heat the aluminum alloy ingot in the melting furnace to 760-800℃ to completely melt it, and release the gas and impurities in the aluminum liquid. Add the remaining raw materials in order of melting point from high to low. After the remaining raw materials have completely melted, remove the impurities. Hold at 720℃ for 10-12 minutes and then pour into the mold for casting. The second step is to perform a single-stage homogenization heat treatment on the cast alloy. The process involves heating the alloy at 90℃ / h from room temperature to 480℃ and holding it at that temperature for 15h. Water cooling is used for the homogenization heat treatment. During the homogenization heat treatment, a large number of submicron-sized dispersed phases are generated in the matrix. Excess Cu atoms tend to aggregate at the interface of the dispersed phases and hinder their long-distance diffusion to the grain boundaries, thereby regulating the distribution of Cu at the grain boundaries. Step 3: The homogenized heat-treated ingot is then subjected to conventional hot forging, solution treatment, and aging. Finally, the intergranular corrosion susceptibility of the alloy is tested according to GB / T7998-2023, and the maximum intergranular corrosion depth of the sample cross-section is photographed using an optical microscope. The added alloying elements form a large number of dispersed phases during the homogenization heat treatment. Cu atoms then segregate at the interface of the dispersed phases, thus hindering their long-distance diffusion to the grain boundaries and achieving Cu distribution at the grain boundaries. By controlling the precipitation behavior of Cu elements, Cu segregation at the grain boundaries is suppressed. At the same time, the stability of the oxide film is improved by the stable oxide formed by the micro-alloying elements, thereby reducing the corrosion depth of the aluminum alloy and improving the corrosion resistance level.

[0025] Example 2: A method for preparing a high corrosion-resistant aluminum alloy material, the specific steps of which are as follows: Step 1: Weigh the raw materials according to the chemical composition in Table 1 by weight percentage. Heat the aluminum alloy ingot in the melting furnace to 760-800℃ to completely melt it, and release the gas and impurities in the aluminum liquid. Add the remaining raw materials in order of melting point from high to low. After the remaining raw materials have completely melted, remove the impurities. After holding at 720℃ for 10-12 minutes, pour it into the mold for casting. The mixture is then poured into a water-cooled copper mold to obtain the final product. The second step involves a two-stage homogenization heat treatment process on the cast alloy, including the following steps: the first stage heat treatment temperature is 280℃, and it is held at this temperature for 8 hours; then the temperature is increased to 480℃ at a rate of 200℃ / h and held for 8 hours; the homogenization heat treatment is cooled by water cooling. Step 3: The two-stage homogenization heat treatment process for the cast alloy includes the following steps: the first stage heat treatment temperature is 280℃ and held at this temperature for 8 hours; then the temperature is increased to 480℃ at a rate of 200℃ / h and held for 8 hours; the homogenization heat treatment cooling method is water cooling; then the ingot after homogenization heat treatment is subjected to conventional hot forging + solution treatment + aging treatment; finally, the intergranular corrosion sensitivity of the alloy is tested according to GB / T7998-2023, and the maximum intergranular corrosion depth of the sample cross section is photographed using an optical microscope.

[0026] Example 3: A method for preparing a high corrosion-resistant aluminum alloy material, the specific steps of which are as follows: Step 1: Weigh the raw materials according to the chemical composition in Table 1 by weight percentage. Heat the aluminum alloy ingot in the melting furnace to 760-800℃ to completely melt it, and release the gas and impurities in the aluminum liquid. Add the remaining raw materials in order of melting point from high to low. After the remaining raw materials have completely melted, remove the impurities. After holding at 720℃ for 10-12 minutes, pour it into the mold for casting. The mixture is then poured into a water-cooled copper mold to obtain the final product. The second step involves a two-stage homogenization heat treatment process on the cast alloy, including the following steps: the first stage heat treatment temperature is 280℃, and it is held at this temperature for 8 hours; then the temperature is increased to 480℃ at a rate of 200℃ / h and held for 8 hours; the homogenization heat treatment is cooled by water cooling. Step 3: The homogenized heat-treated ingot is then subjected to conventional hot forging + solution treatment + aging treatment. Finally, the intergranular corrosion sensitivity of the alloy is tested according to GB / T7998-2023, and the maximum intergranular corrosion depth of the sample cross section is photographed using an optical microscope.

[0027] Example 4: A method for preparing a high corrosion-resistant aluminum alloy material, the specific steps of which are as follows: Step 1: Weigh the raw materials according to the chemical composition in Table 1 by weight percentage. Heat the aluminum alloy ingot in the melting furnace to 760-800℃ to completely melt it, and release the gas and impurities in the aluminum liquid. Add the remaining raw materials in order of melting point from high to low. After the remaining raw materials have completely melted, remove the impurities. After holding at 700-760℃ for 10-12 minutes, pour it into the mold for casting. The mixture is then poured into a water-cooled copper mold to obtain the final product. The second step involves a two-stage homogenization heat treatment process on the cast alloy, including the following steps: the first stage heat treatment temperature is 280℃, and it is held at this temperature for 8 hours; then the temperature is increased to 480℃ at a rate of 200℃ / h and held for 8 hours; the homogenization heat treatment is cooled by water cooling. Step 3: The homogenized heat-treated ingot is then subjected to conventional hot forging + solution treatment + aging treatment. Finally, the intergranular corrosion sensitivity of the alloy is tested according to GB / T7998-2023, and the maximum intergranular corrosion depth of the sample cross section is photographed using an optical microscope.

[0028] Example 5: A method for preparing a high corrosion-resistant aluminum alloy material, the specific steps of which are as follows: Step 1: Weigh the raw materials according to the chemical composition in Table 1 by weight percentage. Heat the aluminum alloy ingot in the melting furnace to 760-800℃ to completely melt it, and release the gas and impurities in the aluminum liquid. Add the remaining raw materials in order of melting point from high to low. After the remaining raw materials have completely melted, remove the impurities. After holding at 700-760℃ for 10-12 minutes, pour it into the mold for casting. The mixture is then poured into a water-cooled copper mold to obtain the final product. The second step involves a two-stage homogenization heat treatment process on the cast alloy, including the following steps: the first stage heat treatment temperature is 280℃, and it is held at this temperature for 8 hours; then the temperature is increased to 480℃ at a rate of 200℃ / h and held for 8 hours; the homogenization heat treatment is cooled by water cooling. Step 3: The homogenized heat-treated ingot is then subjected to conventional hot forging + solution treatment + aging treatment. Finally, the intergranular corrosion sensitivity of the alloy is tested according to GB / T7998-2023, and the maximum intergranular corrosion depth of the sample cross section is photographed using an optical microscope.

[0029] Example 6: A method for preparing a high corrosion-resistant aluminum alloy material, the specific steps of which are as follows: Step 1: Weigh the raw materials according to the chemical composition in Table 1 by weight percentage. Heat the aluminum alloy ingot in the melting furnace to 760-800℃ to completely melt it, and release the gas and impurities in the aluminum liquid. Add the remaining raw materials in order of melting point from high to low. After the remaining raw materials have completely melted, remove the impurities. After holding at 700-760℃ for 10-12 minutes, pour it into the mold for casting. The mixture is then poured into a water-cooled copper mold to obtain the final product. The second step involves a two-stage homogenization heat treatment process on the cast alloy, including the following steps: the first stage heat treatment temperature is 280℃, and the temperature is held for 8 hours; then the temperature is increased to 545℃ at a rate of 200℃ / h and held for 8 hours. The homogenization heat treatment is cooled by water cooling. Step 3: After homogenization and heat treatment, the sample was subjected to routine aging treatment, and then immersed in a 3.5% NaCl solution for 24 hours for testing. The maximum corrosion depth of the sample cross-section was photographed using an optical microscope.

[0030] Example 7: A method for preparing a highly corrosion-resistant aluminum alloy material, the specific steps of which are as follows: Step 1: Weigh the raw materials according to the chemical composition in Table 1 by weight percentage. Heat the aluminum alloy ingot in the melting furnace to 760-800℃ to completely melt it, and release the gas and impurities in the aluminum liquid. Add the remaining raw materials in order of melting point from high to low. After the remaining raw materials have completely melted, remove the impurities. After holding at 700-760℃ for 10-12 minutes, pour it into the mold for casting. The mixture is then poured into a water-cooled copper mold to obtain the final product. The second step involves a two-stage homogenization heat treatment process on the cast alloy, including the following steps: the first stage heat treatment temperature is 280℃, and the temperature is held for 8 hours; then the temperature is increased to 545℃ at a rate of 200℃ / h and held for 8 hours. Step 3: The homogenized heat-treated ingot is then subjected to conventional hot forging + solution treatment + aging treatment. Finally, the intergranular corrosion sensitivity of the alloy is tested according to GB / T7998-2023, and the maximum intergranular corrosion depth of the sample cross section is photographed using an optical microscope.

[0031] Example 8: A method for preparing a high corrosion-resistant aluminum alloy material, the specific steps of which are as follows: Step 1: Weigh the raw materials according to the chemical composition in Table 1 by weight percentage. Heat the aluminum alloy ingot in the melting furnace to 760-800℃ to completely melt it, and release the gas and impurities in the aluminum liquid. Add the remaining raw materials in order of melting point from high to low. After the remaining raw materials have completely melted, remove the impurities. After holding at 700-760℃ for 10-12 minutes, pour it into the mold for casting. The mixture is then poured into a water-cooled copper mold to obtain the final product. The second step involves a two-stage homogenization heat treatment process on the cast alloy, including the following steps: the first stage heat treatment temperature is 280℃, and the temperature is held for 8 hours; then the temperature is increased to 545℃ at a rate of 200℃ / h and held for 8 hours. Step 3: Subsequently, the homogenized heat-treated ingot was subjected to conventional hot forging + solution treatment + aging. Finally, the intergranular corrosion susceptibility of the alloy was tested according to GB / T7998-2023, and the maximum intergranular corrosion depth of the sample cross-section was photographed using an optical microscope. In addition, the dispersed phases within the alloy were analyzed by surface scanning using a transmission electron microscope. The results are as follows: Figure 1 As shown.

[0032] Example 9: A method for preparing a highly corrosion-resistant aluminum alloy material, the specific steps of which are as follows: Step 1: Weigh the raw materials according to the chemical composition in Table 1 by weight percentage. Heat the aluminum alloy ingot in the melting furnace to 760-800℃ to completely melt it, and release the gas and impurities in the aluminum liquid. Add the remaining raw materials in order of melting point from high to low. After the remaining raw materials have completely melted, remove the impurities. After holding at 700-760℃ for 10-12 minutes, pour it into the mold for casting. The mixture is then poured into a water-cooled copper mold to obtain the final product. The second step involves a two-stage homogenization heat treatment process on the cast alloy, including the following steps: the first stage heat treatment temperature is 280℃, and the temperature is held for 8 hours; then the temperature is increased to 545℃ at a rate of 200℃ / h and held for 8 hours. The homogenization heat treatment is cooled by water cooling. Step 3: The homogenized heat-treated ingot is then subjected to conventional hot forging + solution treatment + aging treatment. Finally, the intergranular corrosion sensitivity of the alloy is tested according to GB / T7998-2023, and the maximum intergranular corrosion depth of the sample cross section is photographed using an optical microscope.

[0033] Example 10: A method for preparing a high corrosion-resistant aluminum alloy material, the specific steps of which are as follows: Step 1: Weigh the raw materials according to the chemical composition in Table 1 by weight percentage. Heat the aluminum alloy ingot in the melting furnace to 760-800℃ to completely melt it, and release the gas and impurities in the aluminum liquid. Add the remaining raw materials in order of melting point from high to low. After the remaining raw materials have completely melted, remove the impurities. After holding at 700-760℃ for 10-12 minutes, pour it into the mold for casting. The mixture is then poured into a water-cooled copper mold to obtain the final product. The second step involves a two-stage homogenization heat treatment process on the cast alloy, including the following steps: the first stage heat treatment temperature is 280℃, and the temperature is held for 8 hours; then the temperature is increased to 545℃ at a rate of 200℃ / h and held for 8 hours. The homogenization heat treatment is cooled by water cooling. Step 3: The homogenized heat-treated ingot is then subjected to conventional hot forging + solution treatment + aging treatment. Finally, the intergranular corrosion sensitivity of the alloy is tested according to GB / T7998-2023, and the maximum intergranular corrosion depth of the sample cross section is photographed using an optical microscope.

[0034] Example 11: A method for preparing a high corrosion-resistant aluminum alloy material, the specific steps of which are as follows: Step 1: Weigh the raw materials according to the chemical composition in Table 1 by weight percentage. Heat the aluminum alloy ingot in the melting furnace to 760-800℃ to completely melt it, and release the gas and impurities in the aluminum liquid. Add the remaining raw materials in order of melting point from high to low. After the remaining raw materials have completely melted, remove the impurities. After holding at 700-760℃ for 10-12 minutes, pour it into the mold for casting. The mixture is then poured into a water-cooled copper mold to obtain the final product. The second step involves a two-stage homogenization heat treatment process on the cast alloy, including the following steps: the first stage heat treatment temperature is 280℃ and held at this temperature for 8 hours; then the temperature is increased to 500℃ at a rate of 200℃ / h and held for 8 hours. The homogenization heat treatment is cooled by water cooling. Step 3: The homogenized heat-treated ingot is then subjected to conventional hot forging, solution treatment, and aging. Finally, the intergranular corrosion sensitivity of the alloy is tested according to GB / T7998-2023, and the maximum intergranular corrosion depth of the sample cross-section is photographed using an optical microscope.

[0035] Example 12, a method for preparing a high corrosion-resistant aluminum alloy material, the specific steps of which are as follows: Step 1: Weigh the raw materials according to the chemical composition in Table 1 by weight percentage. Heat the aluminum alloy ingot in the melting furnace to 760-800℃ to completely melt it, and release the gas and impurities in the aluminum liquid. Add the remaining raw materials in order of melting point from high to low. After the remaining raw materials have completely melted, remove the impurities. After holding at 700-760℃ for 10-12 minutes, pour it into the mold for casting. The mixture is then poured into a water-cooled copper mold to obtain the final product. The second step involves a two-stage homogenization heat treatment process on the cast alloy, including the following steps: the first stage heat treatment temperature is 280℃ and held at this temperature for 8 hours; then the temperature is increased to 500℃ at a rate of 200℃ / h and held for 8 hours. The homogenization heat treatment is cooled by water cooling. Step 3: The homogenized heat-treated ingot is then subjected to conventional hot forging + solution treatment + aging treatment. Finally, the intergranular corrosion sensitivity of the alloy is tested according to GB / T7998-2023, and the maximum intergranular corrosion depth of the sample cross section is photographed using an optical microscope.

[0036] Example 13, a method for preparing a high corrosion-resistant aluminum alloy material, the specific steps of which are as follows: Step 1: Weigh the raw materials according to the chemical composition in Table 1 by weight percentage. Heat the aluminum alloy ingot in the melting furnace to 760-800℃ to completely melt it, and release the gas and impurities in the aluminum liquid. Add the remaining raw materials in order of melting point from high to low. After the remaining raw materials have completely melted, remove the impurities. After holding at 700-760℃ for 10-12 minutes, pour it into the mold for casting. The mixture is then poured into a water-cooled copper mold to obtain the final product. The second step involves a two-stage homogenization heat treatment process on the cast alloy, including the following steps: the first stage heat treatment temperature is 280℃ and held at this temperature for 8 hours; then the temperature is increased to 500℃ at a rate of 200℃ / h and held for 8 hours. The homogenization heat treatment is cooled by water cooling. Step 3: The ingot after homogenization heat treatment is then subjected to conventional hot forging + solution treatment + aging treatment. Finally, the sensitivity of the alloy to intergranular corrosion is tested according to GB / T7998-2023, and the maximum intergranular corrosion depth of the sample cross section is photographed using an optical microscope.

[0037] Comparative Example 1: The alloy ingot in Comparative Example 1 was obtained by melting, degassing, and slag removal, and then cast into a water-cooled copper mold. The resulting ingot was then subjected to a two-stage homogenization heat treatment, namely, holding at 280 ℃ for 8 h, and then raising the temperature to 510 ℃ at a rate of 200 ℃ / h and holding at that temperature for 8 h. The homogenization heat treatment was cooled by water cooling. The ingot after homogenization heat treatment was then subjected to conventional hot forging + solution treatment + aging treatment. Finally, the intergranular corrosion sensitivity of the alloy was tested according to GB / T7998-2023, and the maximum intergranular corrosion depth of the sample cross section was photographed using an optical microscope.

[0038] Comparative Example 2: The alloy ingot in Comparative Example 2 was obtained by melting, degassing, and slag removal, and then cast into a water-cooled copper mold. The resulting ingot was then subjected to a two-stage homogenization heat treatment, namely, holding at 280 ℃ for 8 h, and then raising the temperature to 510 ℃ at a rate of 200 ℃ / h and holding at that temperature for 8 h. The homogenization heat treatment was cooled by water cooling. The homogenized heat treatment sample was then immersed in a 3.5% NaCl solution for 24 h for testing, and the maximum corrosion depth of the sample cross-section was photographed using an optical microscope.

[0039] Comparative Example 3: The alloy ingot in Comparative Example 3 was obtained by melting, degassing, and slag removal, and then cast into a water-cooled copper mold. The resulting ingot was then subjected to a two-stage homogenization heat treatment, namely, holding at 280 ℃ for 8 h, and then raising the temperature to 510 ℃ at a rate of 200 ℃ / h and holding at that temperature for 8 h. The homogenization heat treatment was cooled by water cooling. The ingot after homogenization heat treatment was then subjected to conventional hot forging + solution treatment + aging treatment. Finally, the intergranular corrosion sensitivity of the alloy was tested according to GB / T7998-2023, and the maximum intergranular corrosion depth of the sample cross section was photographed using an optical microscope.

[0040] Comparative Example 4: The alloy ingot in Comparative Example 4 was obtained by melting, degassing, and slag removal, and then cast into a water-cooled copper mold. The resulting ingot was then subjected to a two-stage homogenization heat treatment, namely, holding at 280 ℃ for 8 h, and then raising the temperature to 510 ℃ at a rate of 200 ℃ / h and holding at that temperature for 8 h. The homogenization heat treatment was cooled by water cooling. The ingot after homogenization heat treatment was then subjected to conventional hot forging + solution treatment + aging treatment. Finally, the intergranular corrosion sensitivity of the alloy was tested according to GB / T7998-2023, and the maximum intergranular corrosion depth of the sample cross section was photographed using an optical microscope.

[0041] The corrosion results of the alloys in Examples 1-8 and Comparative Examples 1-4 were statistically analyzed, and the results are shown in Table 2. After adding microalloying elements, the maximum corrosion depth of the alloys in Examples 1-8 was significantly lower than that of the alloys in the comparative examples without microalloying elements, and the intergranular corrosion level was also relatively low. This indicates that the addition of microalloying elements significantly enhances the corrosion resistance of the alloys.

[0042] Figure 1 The segregation of Cu, Mg, and Si elements at the dispersed phase interface is shown in the Al-Mg-Si-Cu alloy (Example 7). This indicates that the dispersed phase can adsorb excess Cu, Mg, and Si atoms in the matrix and suppress their large-area segregation at the grain boundaries, thereby achieving the purpose of improving corrosion resistance.

[0043] Table 2. Statistical results of maximum intergranular corrosion depth in the alloys of the examples and comparative examples.

[0044] The above embodiments are only some preferred embodiments of the present invention, and the present invention is not limited thereto. For researchers in the art, the present invention can have various modifications and variations. Any modifications, substitutions, improvements, etc., made within the essence and principles of the present invention should fall within the protection scope of the present invention.

Claims

1. A high corrosion-resistant aluminum alloy material, characterized in that, The high corrosion-resistant aluminum alloy material is a Cu-containing high corrosion-resistant aluminum alloy material, specifically one of the Al-Cu-Mg, Al-Si-Cu, Al-Mg-Si-Cu, and Al-Zn-Mg-Cu alloy systems. The chemical composition of the Cu-containing high corrosion-resistant aluminum alloy material, by weight percentage, includes the following microalloying elements: Mn: 0.1-1.2 wt.%; Cr: 0.05-0.3 wt.%; Mo: 0.05-0.3 wt.%; Sc: 0.05-0.6 wt.%. Zr: 0.05-0.3 wt.%; Yb: 0.05-0.2 wt.%; Hf: 0.05-0.6 wt.%; Er: 0.05-0.15 wt.%; Nb: 0.05-0.15 wt.%; Ni: 0.05-0.2wt.%.

2. The high corrosion-resistant aluminum alloy material according to claim 1, characterized in that, The microalloying elements need to be added in combination, specifically including: Mn+Cr total addition not exceeding 1.5 wt.%, Mn:Cr mass ratio of 4:1~2:1; Mn+Mo total addition not exceeding 1.5 wt.%, Mn:Mo mass ratio of 4:1~2:1; Mn+Zr total addition not exceeding 1.5 wt.%, Mn:Zr mass ratio of 4:1~2:1; Mn+Ni total addition not exceeding 1.4 wt.%, Mn:Mo mass ratio of 6:1~2:1; Zr+Hf total addition not exceeding 0.9 wt.%, Zr:Hf mass ratio of 1:1~1:2; Zr+Sc total addition not exceeding 0.9 wt.%, Zr:Sc mass ratio of 1:1~1:2; Zr+Yb total addition not exceeding 0.5 wt.%, Zr:Yb mass ratio of 3:2~1:1; Zr+Er total addition not exceeding 0.45 wt. The total amount of Zr+Nb composite addition is not more than 0.45 wt.%, with a Zr:Nb mass ratio of 2:1 to 1:1; the total amount of Zr+Ni composite addition is not more than 0.5 wt.%, with a Zr:Ni mass ratio of 3:2 to 1:

1.

3. The high corrosion-resistant aluminum alloy material according to claim 2, characterized in that, The microalloying elements can be added in ternary composites, specifically including: the total amount of Mn+Cr+Mo composite addition not exceeding 1.5 wt.%, with a Mn:Cr:Mo mass ratio of 4:1:1~2:1:1; the total amount of Mn+Cr+Zr composite addition not exceeding 1.8 wt.%, with a Mn:Cr:Zr mass ratio of 4:1:1~2:1:1; the total amount of Mn+Mo+Zr composite addition not exceeding 1.8 wt.%, with a Mn:Mo:Zr mass ratio of 4:1:1~2:1:1; the total amount of Zr+Sc+Hf composite addition not exceeding 1.5 wt.%, with a Zr:Sc:Hf mass ratio of 1:1:1~1:2:2; and the total amount of Zr+Sc+Er ternary composite addition not exceeding 1.05 wt.%, with a Zr:Sc:Er mass ratio of 1:1:1~2:4:

1.

4. The high corrosion-resistant aluminum alloy material according to claim 1, characterized in that, The chemical composition of the Al-Cu-Mg series high corrosion-resistant aluminum alloy material, by weight percentage, includes Cu 3.5-5.0 wt.%, Mg 1.2-1.8 wt.%, with the remainder being Al and unavoidable impurity elements; The chemical composition of the Al-Si-Cu series high corrosion-resistant aluminum alloy material, by weight percentage, includes Cu 1.5-4.0 wt.%, Si 4.5-7.0 wt.%, with the remainder being Al and unavoidable impurity elements; The chemical composition of the Al-Mg-Si-Cu series high corrosion-resistant aluminum alloy material, by weight percentage, includes Cu 0.05-0.6 wt.%, Si 0.4-1.4 wt.%, Mg 0.5-1.2 wt.%, with the remainder being Al and unavoidable impurity elements; The chemical composition of the Al-Zn-Mg-Cu series high corrosion-resistant aluminum alloy material, by weight percentage, includes Cu 1.2-2.0 wt.%, Zn 5.5-7.5 wt.%, Mg 1.5-2.5 wt.%, with the remainder being Al and unavoidable impurity elements.

5. A method for preparing a high corrosion-resistant aluminum alloy material according to any one of claims 1-4, characterized in that, The specific steps are as follows: Step 1: Weigh the raw materials according to the weight percentage of the chemical composition. Heat the aluminum in the melting furnace to 760-800℃ to completely melt it, and release the gas and impurities in the aluminum liquid. Add the remaining raw materials in order of melting point from high to low. After the remaining raw materials have completely melted, remove the impurities. Hold the temperature at 700-760℃ for 10-12 minutes and then pour it into the mold for casting. Step 2: Homogenize the alloy ingot with heat treatment, followed by water cooling; Step 3: For Al-Si-Cu alloys, aging treatment is performed directly after homogenization heat treatment; for Al-Cu-Mg, Al-Mg-Si-Cu, and Al-Zn-Mg-Cu alloys, hot deformation, solution treatment, and aging treatment are performed after homogenization heat treatment.

6. The method for preparing a high corrosion-resistant aluminum alloy material according to claim 5, characterized in that: The homogenization heat treatment includes single-stage and two-stage homogenization heat treatment regimes.

7. The method for preparing a high corrosion-resistant aluminum alloy material according to claim 6, characterized in that: The single-stage homogenization heat treatment process involves raising the temperature from room temperature to the homogenization heat treatment temperature at a rate of 60-120℃ / h and holding it at that temperature for 12-20h. The homogenization heat treatment temperature is selected according to the alloy type: 460-500℃ for Al-Cu-Mg alloys, 500-550℃ for Al-Si-Cu alloys, 520-560℃ for Al-Mg-Si-Cu alloys, and 470-520℃ for Al-Zn-Mg-Cu alloys.

8. The method for preparing a high corrosion-resistant aluminum alloy material according to claim 6, characterized in that: The two-stage homogenization heat treatment process includes the following steps: the first-stage heat treatment temperature is 250-350℃, and the temperature is held for 6-10 hours; then the temperature is increased to the second-stage heat treatment temperature at a rate of 120-300℃ / h and held for 8-14 hours; the second-stage heat treatment temperature is selected according to the alloy type: 460-500℃ for Al-Cu-Mg alloy, 500-550℃ for Al-Si-Cu alloy, 520-560℃ for Al-Mg-Si-Cu alloy, and 470-520℃ for Al-Zn-Mg-Cu alloy.

9. The method for preparing a high corrosion-resistant aluminum alloy material according to claim 5, characterized in that: In the first step, the microalloying elements are added in the form of master alloys during the smelting process, including Al-10Mn master alloy, Al-10Cr master alloy, Al-5Mo master alloy, Al-2Sc master alloy, Al-5Zr master alloy, Al-4Hf master alloy, Al-5Ni master alloy, Al-2Sc master alloy, Al-10Nb master alloy, and Al-5Yb master alloy. Among the main alloying elements, Cu, Mg, and Zn are added as high-purity metals, and Si is added as Al-20Si master alloy.

10. The method for preparing a high corrosion-resistant aluminum alloy material according to claim 5, characterized in that: In the first step, the casting temperature is between 680-710 ℃ for Al-Si alloys and between 700-740 ℃ for Al-Cu-Mg, Al-Mg-Si, and Al-Zn-Mg-Cu alloys.

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