A pre-deformation treatment process to improve the plasticity and corrosion resistance of tri-series aluminum alloy sheets

Abstract

This invention discloses a pre-deformation process for improving the plasticity and corrosion resistance of tri-series aluminum alloy sheets, relating to the field of aluminum alloy processing technology. The process specifically includes the following steps: weighing alloy raw materials according to a ratio and melting and casting them to obtain cast aluminum alloy ingots; subjecting the cast aluminum alloy ingots to a series of processes including secondary heating homogenization, hot deformation, three-stage solution treatment, cold rolling, tensile pre-deformation, aging, compression pre-deformation, secondary aging, and low-temperature annealing to obtain tri-series aluminum alloy sheets with high plasticity and corrosion resistance. This invention achieves grain refinement and uniform element distribution through the synergistic effect of Mg, Al, Ti, B, Sc, and Mn elements during rolling, pre-deformation, and heat treatment, forming a fine, dispersed, and discontinuous β-phase distribution, thereby obtaining aluminum alloy sheets with both high plasticity and excellent resistance to intergranular corrosion, suitable for harsh corrosive environments.

Description

Technical Field

[0001] This invention relates to a pre-deformation process for improving the plasticity and corrosion resistance of three-series aluminum alloy sheets, belonging to the field of aluminum alloy processing technology. Background Technology

[0002] Traditional tri-series aluminum alloys possess excellent corrosion resistance and are widely used in fields requiring high corrosion resistance, such as marine engineering, shipbuilding, and seawater desalination. However, the lack of alloying elements can lead to a deficiency in effective age-hardening phases, making it difficult to further improve their mechanical properties through traditional heat treatment. Furthermore, their resistance to localized corrosion (such as intergranular corrosion) remains insufficient in harsh corrosive environments with high salt and high humidity. Chinese invention patent application CN112322920A discloses a method for producing aluminum alloys by casting, which controls the presence of Zn in the alloy as a solid solution rather than a phase, thereby improving the alloy's strength and subsequent processing performance. This patent improves the thermal stability of the aluminum alloy, but its corrosion resistance advantage is not significant.

[0003] To address the aforementioned issues, this invention adds Mg, Ti, B, and Sc elements to the ternary aluminum alloy, utilizing the resulting β phase to further enhance corrosion resistance and plasticity. However, the β phase tends to precipitate continuously along grain boundaries during aging, forming a network distribution, which can exacerbate intergranular corrosion susceptibility and lead to a decrease in the material's corrosion resistance. Therefore, this invention, while maintaining the good corrosion resistance of the ternary aluminum alloy, achieves a dispersed and discontinuous distribution of the β phase through the synergistic effect of the process, simultaneously improving plasticity and corrosion resistance. Summary of the Invention

[0004] To address the shortcomings of related technologies, this invention provides a pre-deformation treatment process for improving the plasticity and corrosion resistance of ternary aluminum alloy sheets. This process achieves a synergistic improvement in the strength, plasticity, and corrosion resistance of ternary aluminum alloys, while avoiding intergranular corrosion caused by continuous precipitation at grain boundaries. It solves the problems of ternary aluminum alloys lacking effective aging strengthening phases, making it difficult to improve their mechanical properties through traditional heat treatment, and the increased intergranular corrosion sensitivity caused by the continuous precipitation of β phase along grain boundaries.

[0005] The purpose of this invention is to provide a pre-deformation process for improving the plasticity and corrosion resistance of three-series aluminum alloy sheets, specifically including the following steps: (1) Weigh Ti, B, Sc, Mg, Mn and Al according to the proportion, and then smelt and cast them to obtain cast aluminum alloy ingots.

[0006] (2) The cast aluminum alloy ingot is subjected to a second heating homogenization treatment to obtain a homogenized cast aluminum alloy ingot.

[0007] (3) The homogenized cast aluminum alloy ingot is subjected to hot deformation treatment to obtain the hot-deformed cast aluminum alloy ingot.

[0008] (4) The hot-deformed cast aluminum alloy ingot is subjected to a three-stage solution treatment to obtain a solution-treated cast aluminum alloy ingot.

[0009] (5) The solution-treated cast aluminum alloy ingot is cold-rolled to obtain the cold-rolled cast aluminum alloy ingot.

[0010] (6) The cold-rolled cast aluminum alloy ingot is subjected to tensile pre-deformation treatment to obtain the cast aluminum alloy ingot after tensile pre-deformation treatment.

[0011] (7) The pre-deformed cast aluminum alloy ingot is subjected to aging treatment to obtain an aging cast aluminum alloy ingot.

[0012] (8) The aged aluminum alloy ingot is subjected to compression pre-deformation treatment to obtain the compressed pre-deformed aluminum alloy ingot.

[0013] (9) The cast aluminum alloy ingot after compression pre-deformation treatment is subjected to aging treatment again to obtain the cast aluminum alloy ingot after aging treatment.

[0014] (10) The cast aluminum alloy ingot after the second aging treatment is subjected to low temperature annealing to obtain a three-series aluminum alloy plate with high plasticity and corrosion resistance.

[0015] Preferably, the content of each component in the aluminum alloy ingot in step (1) includes, by atomic percentage: 0.15%~0.3% Ti, 0.01%~0.03% B, 0.05%~0.15% Sc, 0.6%~1% Mg, 1.3%~1.5% Mn, with the balance being Al and unavoidable impurities; the smelting temperature is 750℃.

[0016] More preferably, the size of the cast aluminum alloy ingot obtained in step (1) is 550mm×300mm×40mm.

[0017] More preferably, the smelting method in step (1) is vacuum smelting.

[0018] Preferably, the conditions for the second heating homogenization process in step (2) are as follows: heating to 400℃~450℃ at a heating rate of 30℃ / h~60℃ / h and holding for 6h, then heating to 520℃~560℃ at a heating rate of 50℃ / h~70℃ / h and holding for 10h.

[0019] Preferably, the hot deformation treatment in step (3) adopts cross rolling, the hot deformation amount of a single rolling is ≤5%, the total hot deformation amount is 50%, and the rolling temperature is 400℃~450℃.

[0020] More preferably, the speed ratio of the rolls in the cross rolling process of step (3) is 1:1.2.

[0021] Preferably, the conditions for the three-stage solution treatment in step (4) are as follows: the temperature of the first-stage solution treatment is 430℃~450℃ and the solution time is 1h; the temperature of the second-stage solution treatment is 480℃~500℃ and the solution time is 1h; the temperature of the third-stage solution treatment is 520℃~530℃ and the solution time is 1h.

[0022] Preferably, the cold rolling process in step (5) adopts a multi-pass cold rolling process, with a single deformation amount of <4.5%. After each four passes of cold rolling, an intermediate annealing process is performed. The annealing temperature is 300℃~320℃, the holding time is 1~2h, and the total cold rolling deformation amount is 60%.

[0023] Preferably, the stretching rate of the stretching pre-deformation process in step (6) is 1 mm / min, and the total stretching deformation is 5%.

[0024] Preferably, the aging treatment in steps (7) and (9) is low-temperature aging, with an aging temperature of 150℃~180℃ and an aging time of 4h, followed by cooling at a rate of ≤5℃ / min.

[0025] Preferably, the compression pre-deformation treatment in step (8) adopts constant rate compression, with a compression rate of 0.5 mm / min and a total compression amount of 5%, and is unloaded after holding for 3 minutes.

[0026] Preferably, the temperature of the low-temperature annealing treatment in step (10) is 100℃~140℃, the time of the low-temperature annealing treatment is 2~3h, and the low-temperature annealing treatment is followed by cooling.

[0027] Mechanism of the invention: This invention achieves grain refinement of the alloy through the synergistic effect of Ti, B, and Sc elements in rolling, pre-deformation, and heat treatment processes. The addition of Mg generates a β phase in the alloy to improve its corrosion resistance, while simultaneously forming stable intermetallic compounds to limit the continuous growth of the β phase along grain boundaries. In the aluminum alloy material prepared by this invention, intermetallic compound particles are formed between Al, Ti, B, Sc, and Mn elements. These particles act as heterogeneous nucleation cores to refine the as-cast grains, providing a uniform initial microstructure for subsequent processing. This invention effectively eliminates as-cast dendritic segregation through the synergistic effect of rolling, pre-deformation, and heat treatment processes, resulting in… The elements are evenly distributed, while avoiding over-burning of low-melting-point phases; the isotropy is improved, the solid solubility of metallic elements is increased, and more intermetallic compounds that can improve alloy performance are generated. The present invention forms high-density dislocations to provide sufficient nucleation sites for subsequent processes, while eliminating work hardening and avoiding cracking. In addition, the present invention uniformly introduces dislocations, preferentially precipitating fine and dispersed β phases at dislocation sites, consuming part of the supersaturation, and introducing new dislocations on the precipitated phases to break the original precipitation network, forming a fine, dispersed, and discontinuous β phase distribution, effectively avoiding intergranular corrosion caused by continuous precipitation at grain boundaries, and realizing the preparation of aluminum alloys with both high plasticity and corrosion resistance.

[0028] The beneficial effects of this invention are: This invention achieves the formation of the β phase in tri-phase aluminum alloys and makes the β phase discontinuously distributed to increase its corrosion resistance through the synergistic effect of rolling, pre-deformation and heat treatment processes. The synergistic effect of Mg, Al, Ti, B and Sc in the alloy refines the grains and improves the corrosion resistance of the alloy. This invention promotes the refinement of intragranular structure and the growth and refined distribution of corrosion-resistant phases through the coupling of multiple deformation and heat treatment processes, and achieves the simultaneous improvement of plasticity and corrosion resistance.

[0029] This invention utilizes the synergistic effects of three-stage solution treatment, cold rolling deformation, tensile pre-deformation, annealing aging, homogenization treatment, and compression pre-deformation processes to achieve a complete process from composition to microstructure in the alloy sample. This process refines the as-cast grains, homogenizes the dissolved elements, introduces high-density dislocations, and transforms the β-phase from continuous precipitation at grain boundaries to a dispersed, discontinuous distribution within the grains. Finally, annealing eliminates residual stress, resulting in a tri-series aluminum alloy with high plasticity and corrosion resistance. The specific processing flow chart is shown below. Figure 1 As shown. Attached Figure Description

[0030] Figure 1 This is a process flow diagram for processing the three-series aluminum alloy sheet with high plasticity and corrosion resistance according to the present invention.

[0031] Figure 2 This is a temperature-time curve of the processing technology of this invention. Detailed Implementation

[0032] To better illustrate the purpose, technical solution, and advantages of this invention, the following will further describe the invention in conjunction with specific embodiments. In the embodiments and comparative examples of this invention, unless otherwise specified, all chemical reagents used were commercially available analytical grade reagents. The temperature-time curve of the processing technology of this invention is shown below. Figure 2 As shown.

[0033] Example 1 A pre-deformation process for improving the plasticity and corrosion resistance of tri-series aluminum alloy sheets specifically includes the following steps: In this embodiment, the raw materials of each component were weighed according to the atomic percentage composition described in Table 1.

[0034] Table 1 (1) Weigh Ti, B, Sc, Mg, Mn and Al according to the proportions in Table 1, then place them in a heating furnace, evacuate to below 100 Pa, and perform vacuum smelting and casting at 750℃ to obtain a cast aluminum alloy ingot of 550mm×300mm×40mm.

[0035] (2) The cast aluminum alloy ingot is heated from room temperature to 420°C at a heating rate of 50°C / h and held for 6 hours, and then heated to 540°C at a heating rate of 60°C / h and held for 10 hours to obtain the cast aluminum alloy ingot after homogenization treatment.

[0036] (3) The homogenized cast aluminum alloy ingot is cross-rolled under the condition of a roll speed ratio of 1:1.2. The single hot deformation amount of cross rolling is 5%, the total hot deformation amount is 50%, and the rolling temperature is 420℃ to obtain the hot-deformed cast aluminum alloy ingot.

[0037] (4) The hot-deformed cast aluminum alloy ingot is heated to 440°C at a heating rate of 80°C / h and subjected to solution treatment for 1h. Then, it is heated to 490°C at a heating rate of 80°C / h and subjected to solution treatment for 1h. Finally, it is heated to 520°C at a heating rate of 80°C / h and subjected to solution treatment for 1h to obtain the solution-treated cast aluminum alloy ingot.

[0038] (5) The solution-treated cast aluminum alloy ingot is subjected to multiple cold rolling passes. The single deformation amount of cold rolling is 3%, and the total deformation amount is 60%. After each four cold rolling passes, an intermediate annealing treatment is performed. The intermediate annealing temperature is 300℃ and the intermediate annealing time is 1h to obtain the cold-rolled cast aluminum alloy ingot.

[0039] (6) The cold-rolled cast aluminum alloy ingot is subjected to tensile pre-deformation treatment at a stretching rate of 1 mm / min and a total stretching amount of 5% to obtain the cast aluminum alloy ingot after tensile pre-deformation treatment.

[0040] (7) The pre-deformed cast aluminum alloy ingot was subjected to low-temperature aging treatment at 160℃ for 4 hours, and then cooled with the furnace at a cooling rate of 5℃ / min to obtain the aged cast aluminum alloy ingot.

[0041] (8) The aged aluminum alloy ingot is subjected to compression pre-deformation treatment. Constant rate compression is used, with a compression rate of 0.5 mm / min and a total compression amount of 5%. After holding for 3 minutes, the ingot is unloaded to obtain the compressed pre-deformed aluminum alloy ingot.

[0042] (9) The pre-deformed cast aluminum alloy ingot was subjected to a second low-temperature aging treatment at 160°C for 4 hours, and then cooled with the furnace at a cooling rate of 5°C / min to obtain the second-aged cast aluminum alloy ingot.

[0043] (10) The cast aluminum alloy ingot after the second aging treatment was subjected to low-temperature annealing at 120°C for 3 hours. After the annealing was completed, it was air-cooled to room temperature to obtain a three-series aluminum alloy plate with high plasticity and corrosion resistance.

[0044] The aluminum alloy sheet prepared in this embodiment was subjected to performance testing. The test results are shown in Table 7. The test results show that its yield strength is 285 MPa, elongation is 16.5%, and intergranular corrosion depth is 18 μm.

[0045] Example 2 A pre-deformation process for improving the plasticity and corrosion resistance of tri-series aluminum alloy sheets specifically includes the following steps: In this embodiment, the raw materials of each component were weighed according to the atomic percentage composition described in Table 2.

[0046] Table 2 (1) Weigh Ti, B, Sc, Mg, Mn and Al according to the proportions in Table 2, then place them in a heating furnace, evacuate to below 100 Pa, and perform vacuum smelting and casting at 750℃ to obtain a cast aluminum alloy ingot of 550mm×300mm×40mm.

[0047] (2) The cast aluminum alloy ingot is heated from room temperature to 400℃ at a heating rate of 60℃ / h and held for 6h, and then heated to 520℃ at a heating rate of 50℃ / h and held for 10h to obtain the cast aluminum alloy ingot after homogenization treatment.

[0048] (3) The homogenized cast aluminum alloy ingot is cross-rolled under the condition of a roll speed ratio of 1:1.2. The single hot deformation amount of cross rolling is 5%, the total hot deformation amount is 50%, and the rolling temperature is 450℃ to obtain the hot-deformed cast aluminum alloy ingot.

[0049] (4) The hot-deformed cast aluminum alloy ingot is heated to 450°C at a heating rate of 80°C / h and subjected to solution treatment for 1h. Then it is heated to 500°C at a heating rate of 80°C / h and subjected to solution treatment for 1h. Finally, it is heated to 530°C at a heating rate of 80°C / h and subjected to solution treatment for 1h to obtain the solution-treated cast aluminum alloy ingot.

[0050] (5) The solution-treated cast aluminum alloy ingot is subjected to multiple cold rolling passes. The single deformation amount of cold rolling is 3%, and the total deformation amount is 60%. After each four cold rolling passes, an intermediate annealing treatment is performed. The intermediate annealing temperature is 310℃ and the intermediate annealing time is 2h to obtain the cold-rolled cast aluminum alloy ingot.

[0051] (6) The cold-rolled cast aluminum alloy ingot is subjected to tensile pre-deformation treatment at a stretching rate of 1 mm / min and a total stretching amount of 5% to obtain the cast aluminum alloy ingot after tensile pre-deformation treatment.

[0052] (7) The pre-deformed cast aluminum alloy ingot was subjected to low-temperature aging treatment at 180℃ for 4 hours, and then cooled with the furnace at a cooling rate of 5℃ / min to obtain the aged cast aluminum alloy ingot.

[0053] (8) The aged aluminum alloy ingot is subjected to compression pre-deformation treatment. Constant rate compression is used, with a compression rate of 0.5 mm / min and a total compression amount of 5%. After holding for 3 minutes, the ingot is unloaded to obtain the compressed pre-deformed aluminum alloy ingot.

[0054] (9) The pre-deformed cast aluminum alloy ingot was subjected to a second low-temperature aging treatment at 180°C for 4 hours, and then cooled with the furnace at a cooling rate of 5°C / min to obtain the second-aged cast aluminum alloy ingot.

[0055] (10) The cast aluminum alloy ingot after the second aging treatment was subjected to low-temperature annealing at 140°C for 2 hours. After the annealing was completed, it was air-cooled to room temperature to obtain a three-series aluminum alloy plate with high plasticity and corrosion resistance.

[0056] The aluminum alloy sheet prepared in this embodiment was subjected to performance testing. The test results are shown in Table 7. The test results show that its yield strength is 278 MPa, elongation is 16.2%, and intergranular corrosion depth is 20 μm.

[0057] Example 3 A pre-deformation process for improving the plasticity and corrosion resistance of tri-series aluminum alloy sheets specifically includes the following steps: In this embodiment, the raw materials of each component were weighed according to the atomic percentage composition described in Table 3.

[0058] Table 3 (1) Weigh Ti, B, Sc, Mg, Mn and Al according to the proportions in Table 3, then place them in a heating furnace, evacuate to below 100 Pa, and perform vacuum smelting and casting at 750℃ to obtain a cast aluminum alloy ingot of 550mm×300mm×40mm.

[0059] (2) The cast aluminum alloy ingot is heated from room temperature to 450°C at a heating rate of 30°C / h and held for 6 hours, and then heated to 560°C at a heating rate of 70°C / h and held for 10 hours to obtain the cast aluminum alloy ingot after homogenization treatment.

[0060] (3) The homogenized cast aluminum alloy ingot is cross-rolled under the condition of a roll speed ratio of 1:1.2. The single hot deformation amount of cross rolling is 5%, the total hot deformation amount is 50%, and the rolling temperature is 400℃ to obtain the hot-deformed cast aluminum alloy ingot.

[0061] (4) The hot-deformed cast aluminum alloy ingot is heated to 430°C at a heating rate of 70°C / h and subjected to solution treatment for 1h. Then it is heated to 480°C at a heating rate of 80°C / h and subjected to solution treatment for 1h. Finally, it is heated to 525°C at a heating rate of 80°C / h and subjected to solution treatment for 1h to obtain the solution-treated cast aluminum alloy ingot.

[0062] (5) The solution-treated cast aluminum alloy ingot is subjected to multiple cold rolling passes. The single deformation amount of cold rolling is 3%, and the total deformation amount is 60%. After each four cold rolling passes, an intermediate annealing treatment is performed. The intermediate annealing temperature is 320℃ and the intermediate annealing time is 1.5h to obtain the cold-rolled cast aluminum alloy ingot.

[0063] (6) The cold-rolled cast aluminum alloy ingot is subjected to tensile pre-deformation treatment at a stretching rate of 1 mm / min and a total stretching amount of 5% to obtain the cast aluminum alloy ingot after tensile pre-deformation treatment.

[0064] (7) The pre-deformed cast aluminum alloy ingot was subjected to low-temperature aging treatment at 150°C for 4 hours, and then cooled with the furnace at a cooling rate of 5°C / min to obtain the aged cast aluminum alloy ingot.

[0065] (8) The aged aluminum alloy ingot is subjected to compression pre-deformation treatment. Constant rate compression is used, with a compression rate of 0.5 mm / min and a total compression amount of 5%. After holding for 3 minutes, the ingot is unloaded to obtain the compressed pre-deformed aluminum alloy ingot.

[0066] (9) The pre-deformed cast aluminum alloy ingot was subjected to a second low-temperature aging treatment at 150°C for 4 hours, and then cooled with the furnace at a cooling rate of 5°C / min to obtain the second-aged cast aluminum alloy ingot.

[0067] (10) The cast aluminum alloy ingot after the second aging treatment was subjected to low-temperature annealing treatment at 100℃ for 2.5h. After the annealing was completed, it was air-cooled to room temperature to obtain a three-series aluminum alloy plate with high plasticity and corrosion resistance.

[0068] The aluminum alloy sheet prepared in this embodiment was subjected to performance testing. The test results are shown in Table 7. The test results show that its yield strength is 282 MPa, elongation is 16.3%, and intergranular corrosion depth is 19 μm.

[0069] Comparative Example 1 A pre-deformation process for a three-dimensional aluminum alloy sheet specifically includes the following steps: In this comparative example, the raw materials of each component were weighed according to the atomic percentage composition described in Table 4.

[0070] Table 4 (1) Weigh Ti, B, Sc, Mg, Mn and Al according to the proportions in Table 4, then place them in a heating furnace, evacuate to below 100 Pa, and perform vacuum smelting and casting at 750℃ to obtain a cast aluminum alloy ingot of 550mm×300mm×40mm.

[0071] (2) The cast aluminum alloy ingot is heated from room temperature to 420°C at a heating rate of 50°C / h and held for 6 hours, and then heated to 540°C at a heating rate of 60°C / h and held for 10 hours to obtain the cast aluminum alloy ingot after homogenization treatment.

[0072] (3) The homogenized cast aluminum alloy ingot is cross-rolled under the condition of a roll speed ratio of 1:1.2. The single hot deformation amount of cross rolling is 5%, the total hot deformation amount is 50%, and the rolling temperature is 420℃ to obtain the hot-deformed cast aluminum alloy ingot.

[0073] (4) The hot-deformed cast aluminum alloy ingot is heated to 440°C at a heating rate of 80°C / h and subjected to solution treatment for 1h. Then it is heated to 490°C at a heating rate of 80°C / h and subjected to solution treatment for 1h. Then it is placed in cold water for water quenching to obtain the solution-treated cast aluminum alloy ingot.

[0074] (5) The solution-treated cast aluminum alloy ingot is subjected to multiple cold rolling passes. The single deformation amount of cold rolling is 3%, and the total deformation amount is 60%. After each four cold rolling passes, an intermediate annealing treatment is performed. The intermediate annealing temperature is 300℃ and the intermediate annealing time is 1h to obtain the cold-rolled cast aluminum alloy ingot.

[0075] (6) The cold-rolled cast aluminum alloy ingot is subjected to low-temperature aging treatment at 120°C for 3 hours, and then air-cooled to room temperature to obtain a three-series aluminum alloy sheet.

[0076] Comparative Example 2 A pre-deformation process for a three-dimensional aluminum alloy sheet specifically includes the following steps: In this comparative example, the raw materials of each component were weighed according to the atomic percentage composition described in Table 5.

[0077] Table 5 (1) Weigh Ti, B, Sc, Mg, Mn and Al according to the proportions in Table 5, then place them in a heating furnace, evacuate to below 100 Pa, and perform vacuum smelting and casting at 750℃ to obtain a cast aluminum alloy ingot of 550mm×300mm×40mm.

[0078] (2) The cast aluminum alloy ingot is heated from room temperature to 420°C at a heating rate of 40°C / h and held for 6h, and then heated to 540°C at a heating rate of 60°C / h and held for 10h to obtain the cast aluminum alloy ingot after homogenization treatment.

[0079] (3) The homogenized cast aluminum alloy ingot is cross-rolled under the condition of a roll speed ratio of 1:1.2. The single hot deformation amount of cross rolling is 5%, the total hot deformation amount is 50%, and the rolling temperature is 420℃ to obtain the hot-deformed cast aluminum alloy ingot.

[0080] (4) The hot-deformed cast aluminum alloy ingot is heated to 440°C at a heating rate of 80°C / h and subjected to solution treatment for 1h. Then, it is heated to 490°C at a heating rate of 80°C / h and subjected to solution treatment for 1h. Finally, it is heated to 520°C at a heating rate of 80°C / h and subjected to solution treatment for 1h to obtain the solution-treated cast aluminum alloy ingot.

[0081] (5) The solution-treated cast aluminum alloy ingot is subjected to multiple cold rolling passes. The single deformation amount of cold rolling is 3%, and the total deformation amount is 60%. After each four cold rolling passes, an intermediate annealing treatment is performed. The intermediate annealing temperature is 300℃ and the intermediate annealing time is 1h to obtain the cold-rolled cast aluminum alloy ingot.

[0082] (6) The cold-rolled cast aluminum alloy ingot is subjected to tensile pre-deformation treatment at a stretching rate of 1 mm / min and a total stretching amount of 5% to obtain the cast aluminum alloy ingot after tensile pre-deformation treatment.

[0083] (7) The pre-deformed cast aluminum alloy ingot was subjected to low-temperature aging treatment at 120°C for 3 hours, and then air-cooled to room temperature to obtain a three-series aluminum alloy sheet.

[0084] Comparative Example 3 A pre-deformation process for a three-dimensional aluminum alloy sheet specifically includes the following steps: In this comparative example, the raw materials of each component were weighed according to the atomic percentage composition described in Table 6.

[0085] Table 6 (1) Weigh Ti, B, Sc, Mg, Mn and Al according to the proportions in Table 6, then place them in a heating furnace, evacuate to below 100 Pa, and perform vacuum smelting and casting at 750℃ to obtain a cast aluminum alloy ingot of 550mm×300mm×40mm.

[0086] (2) The cast aluminum alloy ingot is heated from room temperature to 420°C at a heating rate of 50°C / h and held for 6 hours, and then heated to 540°C at a heating rate of 60°C / h and held for 10 hours to obtain the cast aluminum alloy ingot after homogenization treatment.

[0087] (3) The homogenized cast aluminum alloy ingot is cross-rolled under the condition of a roll speed ratio of 1:1.2. The single hot deformation amount of cross rolling is 5%, the total hot deformation amount is 50%, and the rolling temperature is 420℃ to obtain the hot-deformed cast aluminum alloy ingot.

[0088] (4) The hot-deformed cast aluminum alloy ingot is heated to 440°C at a heating rate of 80°C / h and subjected to solution treatment for 1h. Then, it is heated to 490°C at a heating rate of 80°C / h and subjected to solution treatment for 1h. Finally, it is heated to 520°C at a heating rate of 80°C / h and subjected to solution treatment for 1h to obtain the solution-treated cast aluminum alloy ingot.

[0089] (5) The solution-treated cast aluminum alloy ingot is subjected to multiple cold rolling passes. The single deformation amount of cold rolling is 3%, and the total deformation amount is 60%. After each four cold rolling passes, an intermediate annealing treatment is performed. The intermediate annealing temperature is 300℃ and the intermediate annealing time is 1h to obtain the cold-rolled cast aluminum alloy ingot.

[0090] (6) The cold-rolled cast aluminum alloy ingot is subjected to tensile pre-deformation treatment at a stretching rate of 1 mm / min and a total stretching amount of 5% to obtain the cast aluminum alloy ingot after tensile pre-deformation treatment.

[0091] (7) The pre-deformed cast aluminum alloy ingot was subjected to low-temperature aging treatment at 160℃ for 4 hours, and then cooled with the furnace at a cooling rate of 5℃ / min to obtain the aged cast aluminum alloy ingot.

[0092] (8) The aged aluminum alloy ingot was subjected to low-temperature annealing at 120°C for 3 hours. After annealing, it was air-cooled to room temperature to obtain a three-series aluminum alloy plate.

[0093] The performance of the aluminum alloy sheets prepared in Examples 1-3 and Comparative Examples 1-3 was tested, and the results are shown in Table 7.

[0094] Table 7 According to the mechanical property data of aluminum alloy sheets prepared by different processes in Table 7, the aluminum alloy sheet prepared in the example has better yield strength, elongation, and intergranular corrosion depth. This indicates that the fine, dispersed, and discontinuous distribution of the β phase can significantly avoid the damage to corrosion resistance caused by continuous precipitation at grain boundaries. The embodiments of the present invention simultaneously improve plasticity through fine grain strengthening and precipitation strengthening systems. Comparative Example 1 uses solution treatment followed by water quenching, cold rolling, and low-temperature annealing without aging treatment. Mg element is dissolved in the matrix and cannot form precipitation strengthening, therefore the yield strength is 195 MPa. Because there is no β phase precipitation, its corrosion resistance is poor (intergranular corrosion depth is 22 μm), but the overall mechanical properties cannot meet the requirements of engineering applications (elongation is 14.0%). Although Comparative Example 1 did not undergo aging, the internal stress and non-equilibrium structure after cold rolling still led to mild intergranular corrosion sensitivity. Its 22 μm corrosion depth is significantly worse than that of the embodiments of this application, proving that excellent corrosion resistance cannot be obtained by solution treatment and cold rolling alone. Comparative Example 2 underwent direct low-temperature annealing after tensile pre-deformation, without aging. The yield strength was 205 MPa, slightly improved only by a small number of dislocations introduced by the tensile pre-deformation (elongation 13.5%), but the strengthening effect was weak. This indicates that pre-deformation without aging is unlikely to have a significant strengthening effect. Furthermore, the aluminum alloy sheet prepared in Comparative Example 2 exhibited poor corrosion resistance (intergranular corrosion depth 24 μm). Comparative Example 3 underwent one aging after tensile pre-deformation, achieving some precipitation strengthening (yield strength 260 MPa). However, the lack of compressive pre-deformation and a second aging process resulted in the β phase tending to precipitate continuously along grain boundaries, leading to poor resistance to intergranular corrosion (intergranular corrosion depth 78 μm). Plasticity was also reduced due to the brittle phase at grain boundaries, with an elongation of only 11%. As demonstrated in Examples 1 and 2, pre-deformation and aging are indispensable. Dislocations introduced by cold deformation alone cannot achieve sustained strengthening; aging is necessary to pin the dislocations to the precipitated phase, thus achieving a synergistic improvement in strength and plasticity. As demonstrated in Examples 3, the second compression pre-deformation and aging can break the original β-phase precipitation network. Through the second aging precipitation, the β-phase is controlled to exhibit a diffuse and discontinuous distribution, which is the core of high plasticity and corrosion resistance. Furthermore, the three-stage solution treatment used in this invention ensures sufficient dissolution of Mg and Mn, providing ample supersaturation for subsequent aging; multi-pass cold rolling and intermediate annealing introduce high-density dislocations and prevent cracking; the sequential design of tensile pre-deformation and compression pre-deformation ensures the uniformity of dislocation distribution and the stepwise control of the precipitation network; finally, low-temperature annealing eliminates residual stress and stabilizes the microstructure. In summary, this invention achieves precise control of the β-phase morphology through multiple process coupling of "double pre-deformation + double aging", resulting in a high-performance tri-series aluminum alloy material with synergistic improvement in strength, plasticity and corrosion resistance. It is suitable for the manufacturing of aerospace and marine engineering components and has significant prospects for industrial application.

[0095] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A pre-deformation treatment process for improving the plasticity and corrosion resistance of tri-series aluminum alloy sheets, characterized in that, Specifically, the following steps are included: (1) Weigh Ti, B, Sc, Mg, Mn and Al according to the proportion, and then smelt and cast them to obtain cast aluminum alloy ingots; (2) The cast aluminum alloy ingot is subjected to a second heating homogenization treatment to obtain a homogenized cast aluminum alloy ingot. (3) The homogenized cast aluminum alloy ingot is subjected to hot deformation treatment to obtain the hot-deformed cast aluminum alloy ingot. (4) The hot-deformed cast aluminum alloy ingot is subjected to a three-stage solution treatment to obtain a solution-treated cast aluminum alloy ingot. (5) The solution-treated cast aluminum alloy ingot is cold-rolled to obtain a cold-rolled cast aluminum alloy ingot. (6) The cold-rolled cast aluminum alloy ingot is subjected to tensile pre-deformation treatment to obtain the tensile pre-deformed cast aluminum alloy ingot. (7) The pre-deformed cast aluminum alloy ingot is subjected to aging treatment to obtain an aging cast aluminum alloy ingot. (8) The aged aluminum alloy ingot is subjected to compression pre-deformation treatment to obtain the compressed pre-deformed aluminum alloy ingot. (9) The cast aluminum alloy ingot after compression pre-deformation treatment is subjected to aging treatment again to obtain the cast aluminum alloy ingot after aging treatment. (10) The cast aluminum alloy ingot after the second aging treatment is subjected to low temperature annealing to obtain a three-series aluminum alloy plate with high plasticity and corrosion resistance.

2. The pre-deformation treatment process for improving the plasticity and corrosion resistance of tri-series aluminum alloy plates according to claim 1, characterized in that, The content of each component in the aluminum alloy ingot in step (1) by atomic percentage includes: 0.15%~0.3% Ti, 0.01%~0.03% B, 0.05%~0.15% Sc, 0.6%~1% Mg, 1.3%~1.5% Mn, with the balance being Al and unavoidable impurities; the smelting temperature is 750℃.

3. The pre-deformation treatment process for improving the plasticity and corrosion resistance of three-series aluminum alloy plates according to claim 1, characterized in that, The conditions for the second heating homogenization process in step (2) are as follows: heating to 400℃~450℃ at a heating rate of 30℃ / h~60℃ / h and holding for 6h, then heating to 520℃~560℃ at a heating rate of 50℃ / h~70℃ / h and holding for 10h.

4. The pre-deformation treatment process for improving the plasticity and corrosion resistance of three-series aluminum alloy plates according to claim 1, characterized in that, The hot deformation treatment in step (3) adopts cross rolling, with a single rolling hot deformation amount of ≤5%, a total hot deformation amount of 50%, and a rolling temperature of 400℃~450℃.

5. The pre-deformation treatment process for improving the plasticity and corrosion resistance of tri-series aluminum alloy plates according to claim 1, characterized in that, The conditions for the three-stage solution treatment in step (4) are as follows: the temperature of the first-stage solution treatment is 430℃~450℃ and the solution time is 1h; the temperature of the second-stage solution treatment is 480℃~500℃ and the solution time is 1h; the temperature of the third-stage solution treatment is 520℃~530℃ and the solution time is 1h.

6. The pre-deformation treatment process for improving the plasticity and corrosion resistance of tri-series aluminum alloy plates according to claim 1, characterized in that, The step (5) cold rolling process adopts a multi-pass cold rolling process, with a single deformation amount of <4.5%. After each four passes of cold rolling, an intermediate annealing process is performed. The annealing temperature is 300℃~320℃, the holding time is 1~2h, and the total cold rolling deformation amount is 60%.

7. The pre-deformation treatment process for improving the plasticity and corrosion resistance of three-series aluminum alloy plates according to claim 1, characterized in that, The stretching rate of the stretching pre-deformation process in step (6) is 1 mm / min, and the total stretching deformation is 5%.

8. The pre-deformation treatment process for improving the plasticity and corrosion resistance of three-series aluminum alloy plates according to claim 1, characterized in that, The aging treatment in steps (7) and (9) is carried out at low temperature, with an aging temperature of 150℃~180℃ and an aging time of 4h. After aging, the temperature is cooled at a rate of ≤5℃ / min.

9. The pre-deformation treatment process for improving the plasticity and corrosion resistance of three-series aluminum alloy plates according to claim 1, characterized in that, The compression pre-deformation process in step (8) adopts constant rate compression, with a compression rate of 0.5 mm / min and a total compression amount of 5%. After holding for 3 minutes, the material is unloaded.

10. The pre-deformation treatment process for improving the plasticity and corrosion resistance of three-series aluminum alloy plates according to claim 1, characterized in that, The temperature of the low-temperature annealing treatment in step (10) is 100℃~140℃, the time of the low-temperature annealing treatment is 2~3h, and the temperature is cooled after the low-temperature annealing treatment.

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