Processing method of wrought aluminum alloy

Abstract

The invention relates to the technical field of non-ferrous metal materials, in particular to a processing method of wrought aluminum alloy. According to the specific technical scheme, an aluminum block is subjected to multi-pass hot rolling to be 6 mm, then homogenized for 6-12 h at the temperature of 465-560 DEG C, then cooled to the room temperature, subjected to multi-pass hot rolling to be 3 mm, naturally cooled to the room temperature, subjected to solution treatment for 0.5-1 h at the temperature of 470-550 DEG C, subjected to water quenching to the room temperature and subjected to multi-pass cold rolling to be 2 mm, the total deformation is 83%, and an alloy plate is obtained; the alloy plate is subjected to solid solution for 10-15 min at the temperature of 480-550 DEG C; and after solid solution is completed, quenching to the room temperature, and after quenching is completed, carrying out artificial aging to obtain the aluminum alloy. And the aluminum block is an Al-Mg-Si-Cu alloy or an Al-Zn-Mg-Cu alloy. The method solves the problems that in the prior art, rolling and heat treatment steps are separated, deformation energy storage and recrystallization processes cannot achieve a synergistic effect, and the alloy strengthening and toughening potential is limited.

Description

Technical Field

[0001] The present invention relates to the technical field of nonferrous metal materials, and in particular to a method for processing a deformed aluminum alloy. Background Art

[0002] Al-Mg-Si-Cu and Al-Zn-Mg-Cu alloys are excellent heat-treatable, rapidly hardening alloys whose primary alloying elements are Mg, Si, and Zn. These alloys offer high strength, toughness, excellent formability, weldability, and corrosion resistance, along with excellent paint hardening capabilities. They are crucial materials for structural components in the automotive, high-speed rail, and aerospace industries.

[0003] The primary strengthening mechanism of Al-Mg-Si-Cu and Al-Zn-Mg-Cu alloys is precipitation strengthening, achieved through rapid quenching to room temperature after solution treatment, followed by artificial aging. The high-density nanoscale precipitates formed during artificial aging effectively strengthen the matrix by inhibiting dislocation motion. Improving the toughness and corrosion resistance of Al-Mg-Si-Cu and Al-Zn-Mg-Cu alloys is currently a hot topic of research in international academia and industry. Providing a highly tough and corrosion-resistant alloy and its corresponding heat treatment process is particularly important.

[0004] In order to improve the strength and ductility of Al-Mg-Si alloys, Sushanta Kumar Panigrahi and R. Jayaganthan published a paper (Development of ultrafine grained Al-Mg-Si alloy with enhanced strength and ductility, 2008), which proposed a composite process of low-temperature rolling (CR) + short-time annealing (155℃ / 5min) + aging treatment (125℃ / 12h). They successfully obtained ultrafine grained structure (grain size 500-1000nm) in Al-Mg-Si alloy and achieved a synergistic improvement of tensile strength of 286MPa and elongation of 14%. However, the study did not involve the study of the corrosion resistance of the alloy, and the industrial applicability of the process parameters (such as rolling deformation of 90% and liquid nitrogen immersion time of 30min / pass) still needs to be verified.

[0005] The paper "Sn-Sc microalloying-induced property improvement and micromechanisms of an AlMgeSi alloy" published by Dehui Zheng et al. investigates the effects of Sn and Sc microalloying on the properties of Al-Mg-Si alloys and their micromechanisms. Compared with the addition of Sn alone, the co-addition of Sn and Sc reduces the particle diameter and increases the number density of the Sc-containing Mg2Si and Mg2(Si,Sn) constituent phases. The modified constituent phases and precipitates enhance the strength, ductility, and corrosion resistance of the peak-aged Al-Mg-Si-Sn-Sc alloy. However, the high price of the added Sc and elements significantly increases material costs, making large-scale application difficult.

[0006] In order to obtain aluminum alloy materials with better performance, researchers from the School of Materials Engineering of Jiangsu University of Technology explored different rolling processes for Al-Zn-Mg-Cu alloy (Effect of Rolling Process on the Microstructure and Properties of Al-Zn-Mg-Cu Alloy, Thermal Processing Technology, 2019, 48(11):110-113). They found that during the rolling process, as the amount of pressure gradually increased, the grains of the alloy were further elongated, and recrystallization occurred along the rolling direction, causing its tensile strength to increase with further pressure. When the maximum deformation was 80%, the alloy reached the optimal tensile strength. However, this study only focused on the rolling process and did not explore the synergistic effect of post-rolling heat treatment (such as aging or solution treatment) on the alloy properties. In actual production, rolling and heat treatment often need to be used in combination.

[0007] The paper "Effect of homogenization time on quench sensitivity of 7085 aluminum alloy" published by Y Zheng et al. investigated the influence of homogenization time on the quench sensitivity of 7085 aluminum alloy. Using optical microscopy, scanning electron microscopy, and X-ray diffraction, they analyzed the elimination of dendritic segregation in the as-cast structure and the dissolution behavior of eutectic phases (such as T and S phases). They also determined an optimal homogenization process (470°C, 24 hours) to reduce quench sensitivity. However, this study was limited to the effect of homogenization on the properties of the aluminum alloy and did not explore whether a thermomechanical heat treatment process combining homogenization with rolling could produce a high-strength, high-toughness, and corrosion-resistant aluminum alloy with even better performance.

[0008] In terms of patent applications, a method for preparing high-strength, tough, weldable, and corrosion-resistant Al-Mg-Zn-Cu alloy (patent application number: 202110030995.6) optimizes the ratio of Mg, Zn, and Cu (such as Zn / Mg≤1.0, Cu / Mg≤0.25) and the deformation heat treatment process. The tensile strength of the alloy reaches 610-690MPa, exceeding that of traditional 7xxx series alloys; through pre-aging (70-95℃ / 24-72h) + cold rolling deformation (5-50% reduction rate) + final aging (100-160℃ / 3-20h), dislocation strengthening and precipitation phase refinement (Cu inhibits precipitation phase coarsening) are used to achieve a synergistic improvement in strength and toughness. This patented process is highly complex and involves multi-step heat treatment (homogenization, solid solution, two-stage aging) and deformation processing (hot rolling + cold rolling), with a long production cycle and high energy consumption.

[0009] A high-strength, tough, and corrosion-resistant 7XXX series aluminum alloy and its preparation method (patent application number: 202410497728.3) introduces microalloying elements such as Zr, Mn, Cr, Sc, and V to form a second phase (such as Al3Zr, Al6Mn, etc.), thereby regulating the layered heterogeneous deformation structure, thereby resolving the contradiction between the strength, toughness, and corrosion resistance of traditional 7XXX series aluminum alloys. The alloy has a tensile strength of over 500 MPa and an elongation of over 10%, indicating that the toughness is significantly improved while maintaining high strength. The elements such as Sc and V added in this patent are relatively expensive (especially Sc), which significantly increases the material cost and has poor economic efficiency.

[0010] An aviation aluminum alloy sheet and its preparation method (patent application number: 202411897891.5) enhances the alloy's strength, toughness, and corrosion resistance by strictly controlling impurities such as Si, Fe, Mn, and Cr (e.g., Si ≤ 0.04%, Fe ≤ 0.07%) and adjusting the ratios of major elements such as Cu, Zn, Mg, and Zr. Be is added to reduce oxide inclusions, while Zr refines the grains. Melt cleanliness is significantly improved through in-furnace powder spray refining, furnace bottom air brick refining, rotary degassing (argon-chlorine mixed gas), and ceramic filtration. This patent relies on high-purity raw materials, resulting in high raw material costs. Al99.95-grade aluminum ingots and Zn99.99-grade zinc ingots are required, and the preparation cost of intermediate alloys (such as AlZr4 and AlBe3) is relatively high. Furthermore, the use of a mixture of argon and chlorine gases, with chlorine being corrosive and toxic, requires additional safety precautions, increasing operational complexity and safety costs.

[0011] An Al-Mg-Si-Cu-Er alloy with a low-sensitivity aging process and its preparation process (patent application number: 202110114538.5) is developed. The ingot is subjected to a two-stage homogenization heat treatment, and the resulting alloy has good room-temperature tensile properties, corrosion resistance, and resistance to natural aging. The two-stage homogenization treatment used in this invention takes a long time, the heat treatment process is relatively cumbersome, and only exfoliation corrosion is tested.

[0012] A multi-stage collaborative treatment method for increasing the paint hardening increment of 6016 aluminum alloy (patent application number: 202111142262.8) involves subjecting cold-rolled sheet to a non-isothermal solution treatment and then to a multi-stage pre-aging treatment to produce a 6016 aluminum alloy with a high paint hardening increment. The treated 6016 aluminum alloy exhibits excellent paint hardening increment and stability against natural aging. However, the heat treatment process is complex, and the impact of the heat treatment process on the corrosion performance of the alloy is not addressed.

[0013] In summary, although existing studies have reported the effects of micro-additions such as Cu-Sc and Sn-Sc and heat treatment processes on the properties of aluminum alloys, the addition of the rare earth element Sc will undoubtedly increase the cost of the material.

[0014] Although existing research has used high-purity raw materials to obtain strong and corrosion-resistant aluminum alloys, high-purity raw materials are often difficult to obtain or are expensive, making them difficult to be widely used in actual production.

[0015] Few existing heat treatment processes can simultaneously improve the mechanical properties and corrosion resistance of aluminum alloys, and the heat treatment process is relatively complex.

[0016] Although existing studies have confirmed that homogenization temperature and time as well as rolling process have a significant impact on the properties of aluminum alloys, there are few reports on the thermomechanical treatment process of coordinated homogenization and rolling at home and abroad. Summary of the Invention

[0017] To address the shortcomings of existing technologies, the present invention provides a method for processing deformed aluminum alloys. This method improves the alloy's performance without affecting its composition. The process for enhancing the alloy's strength, plasticity, and corrosion resistance is simple, highly controllable, and requires less energy. Furthermore, innovative rolling techniques are employed to achieve an aluminum alloy with superior performance without affecting the subsequent artificial aging process. This method addresses the existing problem of separating the rolling and heat treatment steps, preventing the synergistic effects of deformation energy storage and recrystallization, and thus limiting the alloy's potential for strengthening and toughening.

[0018] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0019] The invention discloses a processing method for a deformed aluminum alloy. The invention comprises the following steps: performing multiple hot rolling on an aluminum block to a thickness of 6 mm, homogenizing the block at 465-560° C. for 6-12 hours, cooling the block to room temperature, performing multiple hot rolling on a block to a thickness of 3 mm, naturally cooling the block to room temperature, performing a solution treatment at 470-550° C. for 0.5-1 hour, water quenching the block to room temperature, and performing multiple cold rolling on a block to a thickness of 2 mm with a total deformation of 83% to obtain an alloy plate; performing a solution treatment on the alloy plate at 480-550° C. for 10-15 minutes, quenching the block to room temperature, and artificially aging the block to obtain the deformed aluminum alloy. The aluminum block is an Al-Mg-Si-Cu or Al-Zn-Mg-Cu alloy.

[0020] Preferably, the quenching transfer time does not exceed 10s.

[0021] Preferably, the artificial aging temperature is 120-180° C. and the time is 8-66 hours.

[0022] Preferably, the preparation process of the Al-Mg-Si-Cu alloy is as follows: adding pure aluminum to a melting and holding furnace, maintaining the temperature at 770°C, adding an Al-Si master alloy and an Al-Cu master alloy, stirring and keeping the temperature, and skimming the slag after the alloy is completely melted; then cooling to 720°C, adding an Al-Mg master alloy and continuing to keep the temperature, and after complete melting, refining at 730°C, skimming the slag after refining, and standing for 30 minutes; casting the molten aluminum liquid, during which Al-Ti-B grain refining wire is introduced into the aluminum liquid, and after the casting is completed, obtaining an Al-Mg-Si-Cu alloy cast rod;

[0023] The alloy rods were homogenized by step-wise heating to 565°C and homogenizing at 565°C for 12 h. After that, they were air-cooled to 300°C and then water-mist-cooled to room temperature.

[0024] Preferably, the step-wise heating process is as follows: starting from room temperature, heating to 350°C at a rate of 5°C / min, keeping warm for 1 hour, then heating to 550°C at the same rate, keeping warm for 1 hour, and finally heating to 565°C in 1 hour.

[0025] Preferably, the preparation process of the Al-Zn-Mg-Cu alloy is as follows: pure aluminum is added to a melting and holding furnace, the temperature is maintained at 800°C, an Al-Fe master alloy is added, and after the master alloy is melted, the temperature is maintained at 750°C, Al-Cu master alloy, Al-Cr master alloy, Al-Zr master alloy and Al-Si master alloy are added in sequence, stirred and kept warm, and the slag is skimmed after the alloy is completely melted; then the temperature is lowered to 720°C, Al-Ti master alloy and Al-Zn master alloy are added, and after melting, the temperature is maintained at 700°C, Al-Mg master alloy is added and kept warm, and after complete melting, refining is carried out at 730°C, the slag is skimmed off after refining, and the alloy is allowed to stand for 30 minutes; the molten aluminum liquid is cast, during which Al-Ti-B grain refining wire is introduced into the aluminum liquid, and after the casting is completed, an Al-Zn-Mg-Cu alloy cast rod is obtained;

[0026] The alloy rods were homogenized by step-wise heating to 465°C and homogenizing at 465°C for 24 h, and then naturally cooled to room temperature.

[0027] Preferably, the step-wise heating process is: heating from room temperature to 200°C for 1.5h, and then heating to 465°C for 4h.

[0028] Preferably, the Al-Mg-Si-Cu alloy comprises, by mass percentage, Mg: 1.1%, Si: 0.7%, Cu: 0.3%, Zn: 0.02%, Ti: 0.04%, Fe less than 0.2%, Cr less than 0.2%, Mn less than 0.1%, and the balance being Al.

[0029] Preferably, in terms of mass percentage, the Al-Zn-Mg-Cu alloy includes Zn: 6.21%, Mg: 2.68%, Cu: 1.34%, Fe: 0.18%, Cr: 0.23%, Zr: 0.11%, Si: 0.15%, Ti: 0.034%, Mn less than 0.1%, and the balance is Al.

[0030] The present invention has the following beneficial effects:

[0031] 1. The Al-Mg-Si-Cu alloy and Al-Zn-Mg-Cu alloy obtained after the treatment of the present invention are rolled and then subjected to normal solid solution + artificial peak aging (T6) heat treatment. Compared with the traditional rolled alloy, the hardness, tensile strength, elongation and corrosion resistance of the peak aging alloy can be improved simultaneously.

[0032] 2. The heat treatment process that adopts the coordinated rolling and homogenization has the advantage of strong operability compared with the existing heat treatment processes such as rolling and homogenization, and has further performance improvement based on subsequent heat treatment, providing the possibility of optimizing the performance of aluminum alloys for various heat treatment processes. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is the processing roadmap of the deformed aluminum alloy of the present invention;

[0034] Figure 2 Mechanical property tests of Al-Mg-Si-Cu alloys prepared in Example 1 and Comparative Example 1; (a) shows the hardness curves of the two alloys in the T6 aging state; (b) shows a partial enlarged view of the dotted box in (a); (c) shows the tensile curves of the two alloys in the T6 peak aging state; the artificial aging temperature is 180°C.

[0035] Figure 3 Figures 1 and 2 show the exfoliation corrosion and Tafel curves of the Al-Mg-Si-Cu alloys prepared in Example 1 and Comparative Example 1 under peak aging conditions; (a) is the 5h exfoliation corrosion image of Comparative Example 1; (b) is the 48h exfoliation corrosion image of Comparative Example 1; (c) is the 5h exfoliation corrosion image of Example 1; (d) is the 48h exfoliation corrosion image of Example 1; (e) is the electrochemical Tafel curves of the two alloys;

[0036] Figure 4 Mechanical property tests of Al-Zn-Mg-Cu alloys prepared in Example 2 and Comparative Example 2; (a) shows the hardness curves of the two processes in the T6 aging state; (b) shows a partial enlarged view of the dotted box in (a); (c) shows the tensile curves of the two processes in the T6 peak aging state; the artificial aging temperature is 120°C for both processes.

[0037] Figure 5 Corrosion performance test of Al-Zn-Mg-Cu alloy prepared in Example 2 and Control Example 2 under peak aging state; (a) and (b) are the intergranular corrosion cross-sections of the two processes under a metallographic microscope; (c) is the Tafel curve of the two processes under peak aging state. DETAILED DESCRIPTION

[0038] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0039] Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art.

[0040] The present invention discloses a method for processing deformed aluminum alloys, particularly for Al-Mg-Si-Cu and Al-Zn-Mg-Cu alloys, by adding a homogenizing thermomechanical treatment process during the rolling stage. The as-cast alloy undergoes a series of thermomechanical treatments, including homogenizing heat treatment, hot rolling deformation treatment, homogenizing heat treatment, hot rolling deformation treatment, solution heat treatment, and cold rolling deformation treatment, to produce aluminum alloy sheets with superior performance. This method is applicable to aluminum alloys of other grades, in addition to the two aforementioned alloys.

[0041] The present invention applies the processing method disclosed in the present invention to Al-Mg-Si-Cu alloy and Al-Zn-Mg-Cu alloy to improve the peak hardness, plasticity and corrosion resistance of the alloy after T6 heat treatment. Figure 1 As shown in the figure, the processing of Al-Mg-Si-Cu alloy and Al-Zn-Mg-Cu alloy is described respectively. The specific processes are as follows:

[0042] For Al-Mg-Si-Cu alloys, the processing method includes the following steps:

[0043] (1) Prepare raw materials with corresponding chemical composition ratios;

[0044] (2) First, the molten electrolytic pure aluminum after alkali removal and slag removal is transferred to a tilting melting and holding furnace, the temperature is maintained at 770℃, and the calculated Al-Si master alloy and Al-Cu master alloy are put in, electromagnetically stirred and kept warm, and the slag is removed after the alloy is completely melted; then the temperature is lowered to 720℃, and Al-Mg master alloy is added and kept warm. After the charge is completely melted, it is refined at 730℃ using a refining agent (such as hexachloroethane) and argon with a purity of 99.99%, and the slag is removed after refining. Finally, the melt temperature is maintained at 730℃ and allowed to stand for 30 minutes. The molten aluminum liquid is cast through a vertical shaft casting machine, during which 0.1%-0.3% Al-Ti-B grain refining wire is introduced into the aluminum melt. After casting, Al-Mg-Si-Cu alloy cast rods are obtained;

[0045] (3) The alloy cast rods were cut to 100 mm at the ends and then placed in a homogenizing furnace for homogenization. The temperature was raised in steps to 565°C and homogenized at 565°C for 12 hours. After the temperature was raised, it was cooled to 300°C by air cooling and then cooled to room temperature by water mist cooling. The specific step-by-step heating process was as follows: starting from room temperature, the temperature was raised to 350°C at a rate of 5°C / min, kept at that temperature for 1 hour, then raised to 550°C at the same rate, kept at that temperature for 1 hour, and finally raised to 565°C in 1 hour.

[0046] (4) cutting an aluminum cake from the homogenized aluminum rod, and cutting the aluminum cake into an aluminum block of 92 mm × 35 mm × 12 mm; performing multiple hot rolling, multiple hot rolling to 6 mm (specifically, hot rolling to 10 mm → hot rolling to 8 mm → hot rolling to 6 mm), then homogenizing at 560°C for 6 hours, cooling to room temperature for 10 minutes, and then multiple hot rolling to 3 mm (such as hot rolling to 4 mm → hot rolling to 3 mm), naturally cooling to room temperature, solution treatment at 550°C for 1 hour, water quenching to room temperature, and multiple cold rolling to 2 mm (such as cold rolling to 2.5 mm → cold rolling to 2 mm), with a total deformation of about 83%; obtaining an Al-Mg-Si-Cu alloy plate;

[0047] (5) The obtained Al-Mg-Si-Cu alloy plate was placed in a tube furnace at 550°C for solution treatment for 15 min;

[0048] (6) After the solution is completed, the alloy is taken out and placed in water to quench to room temperature. The quenching transfer time does not exceed 10s;

[0049] (7) After quenching, the alloy was quickly transferred to an oil bath at 180 °C for artificial aging for 8 h.

[0050] For Al-Zn-Mg-Cu alloy, the processing method includes the following steps:

[0051] (1) Prepare raw materials with corresponding chemical composition ratios;

[0052] (2) First, the molten electrolytic pure aluminum after alkali removal and slag removal is transferred to a tilting melting and holding furnace, the temperature of which is maintained at 800℃. The calculated Al-Fe master alloy is placed in it. After the master alloy is melted, the temperature is maintained at 750℃. Al-Cu master alloy, Al-Cr master alloy, Al-Zr master alloy and Al-Si master alloy are added in sequence. Electromagnetic stirring is carried out and the temperature is maintained. After the alloy is completely melted, the slag is removed. The temperature is then lowered to 720℃, and Al-Ti master alloy and Al-Zn master alloy are added. After they are melted, the furnace temperature is maintained at 700℃, and Al-Mg master alloy is added and the temperature is continued to be maintained. After the charge is completely melted, it is refined at 730℃ using a refining agent (such as hexachloroethane) and 99.99% pure argon. The slag is removed after refining. Finally, the melt temperature is maintained at 730℃ and allowed to stand for 30 minutes. The molten aluminum is cast in a vertical casting machine, during which 0.1%-0.3% Al-Ti-B grain refining wire is introduced into the aluminum melt. After the casting is completed, the Al-Zn-Mg-Cu alloy cast rod is obtained;

[0053] (3) The alloy cast rods were cut to 100 mm at the ends and then placed in a homogenizing furnace for homogenization. The temperature was raised in steps to 465°C and homogenized at 465°C for 24 hours. Afterwards, the rods were naturally cooled to room temperature. The specific step-by-step heating process was as follows: the temperature was raised from room temperature to 200°C for 1.5 hours, and then to 465°C for 4 hours.

[0054] (4) cutting an aluminum cake from the homogenized aluminum rod, and cutting the aluminum cake into an aluminum block of 92 mm × 35 mm × 12 mm; performing multiple hot rolling, multiple hot rolling to 6 mm (specifically, hot rolling to 10 mm → hot rolling to 8 mm → hot rolling to 6 mm), then homogenizing at 465 ° C for 12 hours, cooling to room temperature for 10 minutes, and then multiple hot rolling to 3 mm (such as hot rolling to 4 mm → hot rolling to 3 mm), naturally cooling to room temperature, solution treatment at 470 ° C for 30 minutes, water quenching to room temperature, and multiple cold rolling to 2 mm (such as cold rolling to 2.5 mm → cold rolling to 2 mm), with a total deformation of about 83%; obtaining an Al-Zn-Mg-Cu alloy plate;

[0055] (5) The obtained Al-Zn-Mg-Cu alloy plate was placed in a tube furnace at 480°C for solution treatment for 10 min;

[0056] (6) After the solution is completed, the alloy is taken out and placed in water to quench to room temperature. The quenching transfer time does not exceed 10s;

[0057] (7) After quenching, the alloy was quickly transferred to an oil bath at 120 °C for artificial aging for 66 h.

[0058] The present invention will be further described below with reference to specific embodiments.

[0059] The components of the alloys used in the following examples and comparative examples are as follows:

[0060] For Al-Mg-Si-Cu alloys, the alloy composition (by mass percentage) includes: Mg: 1.1%, Si: 0.7%, Cu: 0.3%, and trace amounts of Zn: 0.02%, Ti: 0.04%, and inevitably Fe: less than 0.2%, Cr: less than 0.2%, Mn: less than 0.1%, and the balance is Al. The Al element is added in the form of pure metal, and Si, Cu, Zn, and Ti elements are added in the form of master alloys.

[0061] The Al-Zn-Mg-Cu alloy has an alloy composition (by mass percentage) of 6.21% Zn, 2.68% Mg, 1.34% Cu, and trace amounts of 0.18% Fe, 0.23% Cr, 0.11% Zr, 0.15% Si, and 0.034% Ti. Inevitably, less than 0.1% Mn is present, with the balance being Al. Al is added as pure metal, while Fe, Cr, Zr, Si, Mg, Cu, Zn, and Ti are added as master alloys.

[0062] Example 1

[0063] The main components of the high-strength, corrosion-resistant aluminum alloy material in this embodiment are: Al-1.1Mg-0.7Si-0.3Cu (wt%). The preparation method of the high-strength, toughness, corrosion-resistant aluminum alloy includes the following steps:

[0064] (1) Prepare raw materials with corresponding chemical composition ratios;

[0065] (2) First, the molten electrolytic pure aluminum after de-alkali and slag removal is transferred to a tilting melting and holding furnace, the temperature is maintained at 770℃, and the calculated Al-Si master alloy and Al-Cu master alloy are put in, electromagnetically stirred and kept warm, and the slag is removed after the alloy is completely melted; then the temperature is lowered to 720℃, and Al-Mg master alloy is added and kept warm. After the charge is completely melted, it is refined at 730℃ using a refining agent (hexachloroethane) and argon with a purity of 99.99%, and the slag is removed after refining. Finally, the melt temperature is maintained at 730℃ and allowed to stand for 30 minutes. The molten aluminum liquid is cast through a shaft casting machine, during which 0.1%-0.3% Al-Ti-B grain refining wire is introduced into the aluminum melt. After casting, Al-Mg-Si-Cu alloy cast rods are obtained;

[0066] (3) The alloy cast rods were cut to 100 mm at the ends and then placed in a homogenizing furnace for homogenization. The temperature was raised from room temperature to 350°C at a rate of 5°C / min, held for 1 hour, then raised to 550°C at the same rate, held for 1 hour, and finally raised to 565°C over 1 hour. Homogenization was carried out at 565°C for 12 hours, followed by air cooling to 300°C and water mist cooling to room temperature.

[0067] (4) Cutting aluminum cakes from the homogenized aluminum rods, and cutting the aluminum cakes into aluminum blocks of 92 mm × 35 mm × 12 mm; rolling: hot rolling to 10 mm → hot rolling to 8 mm → hot rolling to 6 mm → homogenization at 560 ° C for 6 h, followed by cooling to room temperature for 10 minutes → hot rolling to 4 mm → hot rolling to 3 mm → natural cooling to room temperature → solution treatment at 550 ° C for 1 h → cold rolling to 2.5 mm → cold rolling to 2 mm, with a total deformation of about 83%, to obtain Al-Mg-Si-Cu alloy plates;

[0068] (5) The obtained Al-Mg-Si-Cu alloy plate was placed in a tube furnace at 550°C for solution treatment for 15 min;

[0069] (6) After the solution is completed, the alloy is taken out and placed in water to quench to room temperature. The quenching transfer time does not exceed 10 seconds;

[0070] (7) After quenching, the alloy was quickly transferred to an oil bath at 180°C for artificial aging.

[0071] Comparative Example 1

[0072] The main components of the aluminum alloy material in this comparative example are: Al-1.1Mg-0.7Si-0.3Cu (wt%). The preparation method of the aluminum alloy includes the following steps:

[0073] (1) Prepare raw materials with corresponding chemical composition ratios;

[0074] (2) First, the molten electrolytic pure aluminum after de-alkali and slag removal is transferred to a tilting melting and holding furnace, the temperature is maintained at 770℃, and the calculated Al-Si master alloy and Al-Cu master alloy are put in, electromagnetically stirred and kept warm, and the slag is removed after the alloy is completely melted; then the temperature is lowered to 720℃, and Al-Mg master alloy is added and kept warm. After the charge is completely melted, it is refined at 730℃ using a refining agent (hexachloroethane) and argon with a purity of 99.99%, and the slag is removed after refining. Finally, the melt temperature is maintained at 730℃ and allowed to stand for 30 minutes. The molten aluminum liquid is cast through a shaft casting machine, during which 0.1%-0.3% Al-Ti-B grain refining wire is introduced into the aluminum melt. After casting, Al-Mg-Si-Cu alloy cast rods are obtained;

[0075] (3) The alloy cast rods were cut to 100 mm at the ends and then placed in a homogenizing furnace for homogenization. The temperature was raised from room temperature to 350°C at a rate of 5°C / min, held for 1 hour, then raised to 550°C at the same rate, held for 1 hour, and finally raised to 565°C over 1 hour. Homogenization was carried out at 565°C for 12 hours, followed by air cooling to 300°C and water mist cooling to room temperature.

[0076] (4) Cutting aluminum cakes from the homogenized aluminum rods into aluminum blocks of 92 mm × 35 mm × 12 mm; and rolling the aluminum cakes: hot rolling to 10 mm → hot rolling to 8 mm → hot rolling to 6 mm → hot rolling to 4 mm → hot rolling to 3 mm → naturally cooling to room temperature → cold rolling to 2.5 mm → cold rolling to 2 mm, with a total deformation of approximately 83%, to obtain Al-Mg-Si-Cu alloy sheets;

[0077] (5) The obtained Al-Mg-Si-Cu alloy plate was placed in a tube furnace at 540°C for solution treatment for 20 min;

[0078] (6) After the solution is completed, the alloy is taken out and placed in water to quench to room temperature. The quenching transfer time does not exceed 10 seconds;

[0079] (7) After quenching, the alloy was quickly transferred to an oil bath at 180°C for artificial aging.

[0080] The mechanical properties of the Al-Mg-Si-Cu alloys prepared in Example 1 and Comparative Example 1 are as follows: Figure 2 The results show that the peak aging hardness increased by 7.3%, and the ultimate tensile strength and elongation increased by 4.1% and 14.6%, respectively. This indicates that the processing method disclosed by the Institute can improve the peak aging hardness and plasticity of Al-Mg-Si-Cu alloy under the T6 heat treatment process.

[0081] The exfoliation corrosion and Tafel curves of the Al-Mg-Si-Cu alloys prepared in Example 1 and Comparative Example 1 under peak aging conditions are shown in Figure 2. Figure 3 As shown, the results show that it exhibits more excellent corrosion resistance in exfoliation corrosion tests and electrochemical tests, indicating that the processing method disclosed in the present invention is beneficial to improving the corrosion resistance of Al-Mg-Si-Cu alloy under the T6 heat treatment process system.

[0082] Example 2

[0083] The main components of the high-strength, corrosion-resistant aluminum alloy material in this embodiment are: Al-Zn-Mg-Cu. The preparation method of the high-strength, toughness, corrosion-resistant aluminum alloy includes the following steps:

[0084] (1) Prepare raw materials with corresponding chemical composition ratios;

[0085] (2) First, the molten electrolytic pure aluminum after alkali removal and slag removal is transferred to a tilting melting and holding furnace. The temperature is maintained at 800℃ and the calculated Al-Fe master alloy is added. After the master alloy is melted, the temperature is maintained at 750℃. Al-Cu master alloy, Al-Cr master alloy, Al-Zr master alloy and Al-Si master alloy are added in sequence. Electromagnetic stirring is carried out and the temperature is kept. After the alloy is completely melted, the slag is removed. Then the temperature is lowered to 720℃, and Al-Ti master alloy and Al-Zn master alloy are added. After they are melted, the furnace temperature is maintained at 700℃ and Al-Mg master alloy is added and the temperature is continued to be kept. After the charge is completely melted, it is refined at 730℃ using a refining agent (such as hexachloroethane) and 99.99% pure argon. After refining, the slag is removed. Finally, the melt temperature is maintained at 730℃ and allowed to stand for 30 minutes. The molten aluminum is cast in a vertical casting machine, during which 0.1%-0.3% Al-Ti-B grain refining wire is introduced into the aluminum melt. After the casting is completed, the Al-Zn-Mg-Cu alloy cast rod is obtained;

[0086] (3) Cut the alloy casting rod to 100 mm at the end and place it in a homogenizing furnace for homogenization. Heat it from room temperature to 200°C for 1.5 hours, then heat it to 465°C for 4 hours, homogenize it at 465°C for 24 hours, and then cool it naturally to room temperature.

[0087] (4) Cutting aluminum cakes from the homogenized aluminum rods, and cutting the aluminum cakes into aluminum blocks of 92 mm × 35 mm × 12 mm; rolling: hot rolling to 10 mm → hot rolling to 8 mm → hot rolling to 6 mm → homogenization at 465 ° C for 12 h, then cooling to room temperature for 10 minutes → hot rolling to 4 mm → hot rolling to 3 mm → naturally cooling to room temperature → solution treatment at 470 ° C for 30 min, water quenching to room temperature → cold rolling to 2.5 mm → cold rolling to 2 mm, with a total deformation of about 83%, to obtain Al-Zn-Mg-Cu alloy plates;

[0088] (5) The obtained Al-Zn-Mg-Cu alloy plate was placed in a tube furnace at 480°C for solution treatment for 10 min;

[0089] (6) After the solution is completed, the alloy is taken out and placed in water to quench to room temperature. The quenching transfer time does not exceed 10s;

[0090] (7) After quenching, the alloy was quickly transferred to an oil bath at 120 °C for artificial aging.

[0091] Comparative Example 2

[0092] The main components of the aluminum alloy material in this comparative example are: Al-Zn-Mg-Cu. The preparation method of the aluminum alloy includes the following steps:

[0093] (1) Prepare raw materials with corresponding chemical composition ratios;

[0094] (2) First, the molten electrolytic pure aluminum after alkali removal and slag removal is transferred to a tilting melting and holding furnace. The temperature is maintained at 800℃ and the calculated Al-Fe master alloy is added. After the master alloy is melted, the temperature is maintained at 750℃. Al-Cu master alloy, Al-Cr master alloy, Al-Zr master alloy and Al-Si master alloy are added in sequence. Electromagnetic stirring is carried out and the temperature is kept. After the alloy is completely melted, the slag is removed. Then the temperature is lowered to 720℃, and Al-Ti master alloy and Al-Zn master alloy are added. After they are melted, the furnace temperature is maintained at 700℃ and Al-Mg master alloy is added and the temperature is continued to be kept. After the charge is completely melted, it is refined at 730℃ using a refining agent (such as hexachloroethane) and 99.99% pure argon. After refining, the slag is removed. Finally, the melt temperature is maintained at 730℃ and allowed to stand for 30 minutes. The molten aluminum is cast in a vertical casting machine, during which 0.1%-0.3% Al-Ti-B grain refining wire is introduced into the aluminum melt. After the casting is completed, the Al-Zn-Mg-Cu alloy cast rod is obtained;

[0095] (3) Cut the alloy casting rod to 100 mm at the end and place it in a homogenizing furnace for homogenization. Heat it from room temperature to 200°C for 1.5 hours, then heat it to 465°C for 4 hours, homogenize it at 465°C for 24 hours, and then cool it naturally to room temperature.

[0096] (4) Cutting aluminum cakes from the homogenized aluminum rods into aluminum blocks of 92 mm × 35 mm × 12 mm; and rolling the aluminum cakes: hot rolling to 10 mm → hot rolling to 8 mm → hot rolling to 6 mm → hot rolling to 4 mm → hot rolling to 3 mm → naturally cooling to room temperature → cold rolling to 2.5 mm → cold rolling to 2 mm, with a total deformation of approximately 83%, to obtain Al-Zn-Mg-Cu alloy sheets;

[0097] (5) The obtained Al-Zn-Mg-Cu alloy plate was placed in a tube furnace at 480°C for solution treatment for 20 min;

[0098] (6) After the solution is completed, the alloy is taken out and placed in water to quench to room temperature. The quenching transfer time does not exceed 10 seconds;

[0099] (7) After quenching, the alloy was quickly transferred to an oil bath at 120 °C for artificial aging.

[0100] The mechanical properties of the Al-Zn-Mg-Cu alloys prepared in Example 2 and Comparative Example 2 are as follows: Figure 4 The results show that the peak aging hardness increased by 1.7%, and the ultimate tensile strength and elongation increased by 2.2% and 32.1% respectively. This shows that the processing method disclosed in the present invention can improve the peak aging hardness and plasticity of Al-Zn-Mg-Cu alloy under the T6 heat treatment process.

[0101] The corrosion performance and Tafel curve of the Al-Zn-Mg-Cu alloy prepared in Example 2 and Comparative Example 2 under peak aging conditions are as follows: Figure 5 As shown in the results, the intergranular corrosion test showed a shallower intergranular corrosion depth. At the same time, the Tafel curve in the electrochemical test showed that the corrosion electrode potential of Example 2 was higher than that of Control Example 2, both indicating that Example 2 has better corrosion resistance. This proves that the processing method disclosed in the present invention is conducive to improving the corrosion resistance of Al-Zn-Mg-Cu alloy under the T6 heat treatment process.

[0102] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A method for processing a deformed aluminum alloy, characterized in that: The aluminum block is subjected to multiple hot rolling to 6 mm, then homogenized at 465-560° C. for 6-12 hours, cooled to room temperature, and then subjected to multiple hot rolling to 3 mm. After naturally cooling to room temperature, the block is solution treated at 470-550° C. for 0.5-1 hour, water quenched to room temperature, and then cold rolled to 2 mm with a total deformation of 83% to obtain an alloy plate. The alloy plate is solution treated at 480-550° C. for 10-15 minutes. After the solution treatment is completed, the plate is quenched to room temperature. After the quenching is completed, the plate is artificially aged to obtain the aluminum block. The aluminum block is an Al-Mg-Si-Cu or Al-Zn-Mg-Cu alloy.

2. The method for processing a deformed aluminum alloy according to claim 1, wherein: The quenching transfer time shall not exceed 10s.

3. The method for processing a deformed aluminum alloy according to claim 1, wherein: The temperature of artificial aging is 120-180℃ and the time is 8-66h.

4. The method for processing a deformed aluminum alloy according to claim 1, wherein: The Al-Mg-Si-Cu alloy preparation process comprises the following steps: adding pure aluminum to a melting and holding furnace, maintaining the temperature at 770° C., adding an Al-Si master alloy and an Al-Cu master alloy, stirring and holding the mixture, and skimming the slag after the alloy is completely melted; then cooling the mixture to 720° C., adding the Al-Mg master alloy, and continuing to hold the mixture; and after complete melting, refining the mixture at 730° C., skimming the slag, and allowing the mixture to stand for 30 minutes; and casting the molten aluminum liquid, during which an Al-Ti-B grain refining wire is introduced into the aluminum liquid, to obtain an Al-Mg-Si-Cu alloy cast rod. The alloy rods were homogenized by step-wise heating to 565°C and homogenizing at 565°C for 12 h. After that, they were air-cooled to 300°C and then water-mist-cooled to room temperature.

5. The method for processing a deformed aluminum alloy according to claim 4, characterized in that: The step heating process is as follows: starting from room temperature, heating to 350°C at 5°C / min, keeping warm for 1 hour, then heating to 550°C at the same speed, keeping warm for 1 hour, and finally heating to 565°C in 1 hour.

6. The method for processing a deformed aluminum alloy according to claim 1, wherein: The preparation process of the Al-Zn-Mg-Cu alloy is as follows: pure aluminum is added to a melting and holding furnace, the temperature is maintained at 800° C., an Al-Fe master alloy is added, and after the master alloy is melted, the temperature is maintained at 750° C., an Al-Cu master alloy, an Al-Cr master alloy, an Al-Zr master alloy, and an Al-Si master alloy are added in sequence, stirred and kept warm, and slag is skimmed after the alloy is completely melted; then the temperature is lowered to 720° C., an Al-Ti master alloy and an Al-Zn master alloy are added, and after melting, the temperature is maintained at 700° C., an Al-Mg master alloy is added, and the temperature is continued to be kept warm, and after complete melting, refining is performed at 730° C., the slag is skimmed off after refining, and the alloy is allowed to stand for 30 minutes; the molten aluminum liquid is cast, during which Al-Ti-B grain refining wire is introduced into the aluminum liquid, and after the casting is completed, an Al-Zn-Mg-Cu alloy cast rod is obtained; The alloy rods were homogenized by step-wise heating to 465°C and homogenizing at 465°C for 24 h, and then naturally cooled to room temperature.

7. The method for processing a deformed aluminum alloy according to claim 6, characterized in that: The step-by-step heating process is: heating from room temperature to 200°C for 1.5h, and then heating to 465°C for 4h.

8. The method for processing a deformed aluminum alloy according to claim 1, wherein: In terms of mass percentage, the Al-Mg-Si-Cu alloy includes Mg: 1.1%, Si: 0.7%, Cu: 0.3%, Zn: 0.02%, Ti: 0.04%, Fe: less than 0.2%, Cr: less than 0.2%, Mn: less than 0.1%, and the balance is Al.

9. The method for processing a deformed aluminum alloy according to claim 1, wherein: In terms of mass percentage, the Al-Zn-Mg-Cu alloy includes Zn: 6.21%, Mg: 2.68%, Cu: 1.34%, Fe: 0.18%, Cr: 0.23%, Zr: 0.11%, Si: 0.15%, Ti: 0.034%, Mn less than 0.1%, and the balance is Al.

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