Method for improving precipitation strengthening effect of aluminum-lithium alloy based on three-way compression deformation and application

Abstract

The invention discloses a heat treatment method for improving the precipitation strengthening effect of an aluminum-lithium alloy based on three-way compression deformation and application. Belongs to the technical field of aluminum-lithium alloy heat treatment. According to the method, within 10 min after solution treatment, firstly, 5%-10% high-temperature compression deformation is carried out in the length direction of the alloy plate at the compression temperature of 100-200 DEG C, then the direction of the plate is changed, 10%-15% low-temperature compression deformation is carried out in the width direction of the alloy plate at the compression temperature of-50 DEG C to-100 DEG C, and then the direction of the alloy plate is changed. 5%-10% high-temperature compression deformation is conducted in the thickness direction, and the compression temperature ranges from 120 DEG C to 250 DEG C. Compared with conventional one-way pre-stretching, the variable temperature-three-way pre-compression deformation can greatly promote precipitation of a main strengthening phase T1 phase, the precipitation strengthening effect of the alloy is effectively improved, and collaborative improvement of the alloy strength and the ductility is achieved.

Description

Technical Field

[0001] The present invention relates to a heat treatment method for aluminum-lithium alloys, and in particular to a heat treatment method and application thereof for enhancing the precipitation strengthening effect of aluminum-lithium alloys based on three-dimensional compression deformation, belonging to the technical field of heat treatment of aluminum-lithium alloys. Background Art

[0002] Compared with traditional aluminum alloys, aluminum-lithium alloys have the advantages of low density, high specific strength, large elastic modulus, and good corrosion resistance, and have broad application prospects in the military and aerospace fields. The mechanical properties of aluminum-lithium alloys are mainly related to the main strengthening phase formed during the aging process - the T1 phase. This phase is disc-shaped and has an HCP structure, which can effectively hinder the movement of dislocations, thereby improving the mechanical properties of the alloy. However, due to the high stacking fault energy of aluminum, the transformation from FCC to HCP structure requires a very large driving force, resulting in difficulty in the nucleation of the T1 phase and limited improvement in the mechanical properties of the alloy. Pre-deformation is the most common and effective method to promote the nucleation of the T1 phase. The pre-deformation process can introduce dislocations to provide non-uniform nucleation particles for the nucleation of the T1 phase, reduce the nucleation energy barrier of the T1 phase, and thus effectively improve the strength of the alloy. However, the traditional single-phase pre-deformation introduces a single type of dislocations and has a low dislocation density, which still has great limitations in promoting the nucleation of the T1 phase. Therefore, developing a new pre-deformation process and improving the Burgers vector and density of dislocations can more effectively promote the mechanical properties of the main strengthening phase T1 phase, thereby effectively improving the mechanical properties of the alloy. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to propose a pre-deformation heat treatment process system that promotes the high-density precipitation of the primary strengthening phase, the T1 phase, with fine size. Specifically, a method for enhancing the precipitation strengthening effect of aluminum-lithium alloys based on triaxial compression deformation is provided. Traditional pre-deformation primarily involves uniaxial pre-stretching, resulting in dislocations that slip only on a single {111} close-packed plane, thus limiting their ability to promote the heterogeneous nucleation of the T1 phase. In contrast, the present invention employs triaxial compression deformation, which involves a 5% to 10% compression deformation along the length of the alloy sheet at a temperature of 100°C to 200°C. The sheet is then reoriented and subjected to a 10% to 15% compression deformation along the width of the sheet at a temperature of -50°C to -100°C. The sheet is then reoriented again and subjected to a 5% to 10% compression deformation along the thickness of the sheet at a temperature of 120°C to 250°C. This temperature-variable, triaxial compression deformation simultaneously activates dislocations on different slip planes, thereby generating a three-dimensional dislocation network and dislocation steps. This dislocation configuration is more conducive to the nucleation of the T1 phase. At the same time, the high density of dislocations provides more nucleation sites for the nucleation of the T1 phase. After artificial aging treatment at 155°C to 175°C for 10 to 20 hours, the size of the T1 phase is significantly refined, with an average diameter of 35 to 45 nm, significantly smaller than that of conventional unidirectional pre-deformation. This effectively improves the strength and elongation of the alloy.

[0004] At the same time, the present invention provides an aluminum-lithium alloy heat treatment method based on three-dimensional compression deformation for use in the preparation of profiles, plates and forgings involved in the fields of aerospace, national defense and military industry, high-speed rail, automobiles, bicycles, pressure vessels, construction, and photovoltaics.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: A method for enhancing the precipitation strengthening effect of aluminum-lithium alloy based on three-dimensional compression deformation, comprising the following steps: S01, prepare aluminum-lithium alloy ingot: the aluminum-lithium alloy ingot is an Al-Cu-Li series aluminum alloy, in which the Cu element accounts for 1.5~5.5wt.%, the Li element accounts for 0.6~1.5wt.%, the Mg element accounts for 0.4~1.2wt.%, the Ag element accounts for 0.5~1.2wt.%, the Zr element accounts for 0.05~0.2wt% and the balance is Al.

[0006] S02, subjecting the aluminum-lithium alloy ingot to a homogenization heat treatment: heating the ingot to 500-520°C at a heating rate of 50-60°C / h and keeping the temperature for 12-24 hours, and finally air-cooling the ingot to room temperature to obtain an ingot 1; S03, heating treatment: ingot 1 is heated at 440°C to 520°C for 10h to 30h to obtain ingot 2; S04, hot rolling: Ingot 2 is directly taken out of the furnace for hot rolling, and is hot rolled in 5-15 passes to a diameter of 4-8 mm. Each hot rolling pass is returned to the furnace and kept warm for at least 5 minutes to obtain plate 1; S05, solution treatment: Plate 1 is directly solution treated after hot rolling. Solution treatment process: holding temperature is 480°C~520°C, holding time is 10min~6h, then water quenching to room temperature to obtain plate 2; S06, pre-deformation: perform 5%-10% compression deformation along the length direction of plate 2 at a compression temperature of 100°C-200°C, then change the direction of plate 2 and perform 10%-15% compression deformation along the width direction of plate 2 at a compression temperature of -50°C--100°C, then change the direction of plate 2 again and perform 5%-10% compression deformation along the thickness direction at a compression temperature of 120°C-250°C to obtain plate 3; S07, Aging: After the plate is air-cooled to room temperature, it is left for 5h~12h, and then artificially aged at 155℃~175℃ for 10~20h. After artificial aging, it is cooled to room temperature.

[0007] The aluminum-lithium alloy is obtained by the method of the present invention.

[0008] The aluminum-lithium alloy of the present invention is used in aerospace, national defense and military industry, high-speed rail, automobiles, bicycles, pressure vessels, construction, and photovoltaic materials.

[0009] Preferably, the material includes profiles, plates and forgings.

[0010] An aerospace material is prepared from the aluminum-lithium alloy of the present invention.

[0011] A national defense military material is prepared from the aluminum-lithium alloy of the present invention.

[0012] A high iron material is prepared from the aluminum-lithium alloy of the present invention.

[0013] An automobile material is prepared from the aluminum-lithium alloy of the present invention.

[0014] A bicycle material is prepared from the aluminum-lithium alloy of the present invention.

[0015] A pressure vessel material is prepared from the aluminum-lithium alloy of the present invention.

[0016] A building material is prepared from the aluminum-lithium alloy of the present invention.

[0017] A photovoltaic material is prepared from the aluminum-lithium alloy of the present invention.

[0018] The present invention has the following beneficial effects: In the prior art, in order to improve the mechanical properties of aluminum-lithium alloys, aluminum-lithium alloys are usually subjected to a certain amount of pre-deformation after solution treatment to introduce dislocations and promote the formation of the main strengthening phase T1, thereby effectively improving the mechanical properties of the alloy. However, traditional pre-deformation is all unidirectional tensile deformation, which has a relatively limited effect on improving the precipitation strengthening of the alloy and will cause a significant reduction in the elongation of the alloy, resulting in the application of the alloy being still limited. The present invention relates to a heat treatment process based on three-dimensional compression deformation to improve the precipitation strengthening effect of aluminum-lithium alloys. The pre-deformation process is as follows: within 10 minutes after the solution treatment, the alloy plate is first subjected to a high-temperature compression deformation of 5% to 10% along the length direction of the alloy plate, and the compression temperature is 100°C to 200°C; then the direction of the plate is changed, and a low-temperature compression deformation of 10% to 15% is performed along the width direction of the alloy plate, and the compression temperature is -50°C to -100°C; then the direction of the alloy plate is changed again, and a high-temperature compression deformation of 5% to 10% is performed along the thickness direction, and the compression temperature is 120°C to 250°C; then, after air cooling to room temperature and standing for 5h-12h, an artificial aging treatment is performed at 155°C to 175°C for 10-20h. Compared with conventional unidirectional pre-stretching, the variable temperature-three-directional pre-compression deformation of the present invention can greatly promote the precipitation of the main strengthening phase T1 phase, effectively improve the precipitation strengthening effect of the alloy, and achieve a synergistic improvement in the strength and elongation of the alloy. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 EBSD images of the grain structures of the alloys of Example 1, Comparative Example 1 and Comparative Example 5 after aging, (a) Example 1, (b) Comparative Example 1, (c) Comparative Example 5; Figure 2 TEM bright field images of the alloys of Example 1, Comparative Example 1, and Comparative Example 5 during peak aging, (a) Example 1, (b) Comparative Example 1, (c) Comparative Example 5. DETAILED DESCRIPTION

[0020] The present invention will be further described in detail below with reference to specific examples. The following examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention. Example 1

[0021] The experimental alloy's composition is Al-4Cu-1Li-0.4Mg-0.5Ag-0.11Zr. This means that in this Al-Cu-Li alloy, Cu accounts for 4 wt.%, Li accounts for 1.0 wt.%, Mg accounts for 0.4 wt.%, Ag accounts for 0.5 wt.%, Zr accounts for 0.11 wt.%, and the balance is Al.

[0022] The alloy is prepared using 99.98% commercially pure aluminum, pure Mg, pure Li, pure Ag, and Al-Cu and Al-Zr master alloys as raw materials. The alloy is vacuum-casted. First, pure aluminum is smelted in a resistance furnace. Once the aluminum is melted, the master alloy and other pure metals are added. Degassing and slag removal are performed during the smelting process to minimize the effects of gases and inclusions on the ingot structure. Subsequently, the aluminum alloy is cast in a cylindrical water-cooled mold at 760°C to obtain an aluminum alloy ingot.

[0023] Then, a homogenization heat treatment was performed, heating the temperature to 500℃ at a rate of 50℃ / h and keeping the temperature for 24h, and finally air-cooling to room temperature. 3 The homogenized samples were heated at 460°C for 10 hours, then hot-rolled from 20 mm to 6 mm in six passes, with each pass followed by a 5-minute heat-reinforcement cycle. The rolled plates were solution treated at 520°C for 2 hours and then quenched in water to room temperature.

[0024] After solution treatment for 5 minutes, three-dimensional compression deformation was carried out. The plate was compressed by 8% in the longitudinal direction at a compression temperature of 200°C. Then the plate direction was changed and the plate was compressed by 10% in the width direction at a compression temperature of -50°C. Then the plate direction was changed again and the plate was compressed by 8% in the thickness direction at a compression temperature of 170°C. After air cooling to room temperature and standing for 5 hours, the plate was subjected to artificial aging heat treatment at 165°C for 14 hours.

[0025] The aluminum-lithium alloy obtained by the method of this embodiment.

[0026] The aluminum-lithium alloy of this embodiment is used in aerospace, national defense and military industry, high-speed rail, automobiles, bicycles, pressure vessels, construction, and photovoltaic materials.

[0027] Preferably, the material includes profiles, plates and forgings.

[0028] An aerospace material is prepared from the aluminum-lithium alloy of this embodiment.

[0029] A national defense and military material is prepared from the aluminum-lithium alloy of this embodiment.

[0030] A high-iron material is prepared from the aluminum-lithium alloy of this embodiment.

[0031] An automotive material is prepared from the aluminum-lithium alloy of this embodiment.

[0032] A bicycle material is prepared from the aluminum-lithium alloy of this embodiment.

[0033] A pressure vessel material is prepared from the aluminum-lithium alloy of this embodiment.

[0034] A building material is prepared from the aluminum-lithium alloy of this embodiment.

[0035] A photovoltaic material is prepared from the aluminum-lithium alloy of this embodiment.

[0036] Room-temperature tensile testing was performed on the alloys at a rate of 1 mm / min using an MTS C43.504 testing machine. Three parallel specimens were tested for each sample. After fracture, the yield strength σs, tensile strength σb, and elongation δ were calculated according to the national standard GBT228-2002. The alloy's microstructure was observed using transmission electron microscopy, while atomic-resolution HAADF-STEM was performed using a spherical aberration-corrected electron microscope with an accelerating voltage of 300 kV. Transmission samples were prepared using an electrolytic double-spray apparatus. The double-spray solution consisted of 70% methanol and 30% nitric acid, with a temperature of -25°C to -30°C, a voltage of 15 to 20 V, and a current of 50 to 70 mA.

[0037] Comparative Examples 1 to 6 are basically the same as Example 1, and the alloy composition design, subsequent deformation and processing are basically the same. The difference lies in the different pre-deformation processes.

[0038] In Comparative Example 1, the deformation in the longitudinal direction is 8%, and the compression temperature in the longitudinal direction is 200°C; the deformation in the width direction is 10%, and the compression temperature in the width direction is -50°C; In Comparative Example 2, the deformation amount was 10% only in the longitudinal direction and the compression temperature was room temperature; In Comparative Example 3, the deformation in the longitudinal direction is 4%, and the compression temperature in the longitudinal direction is 200°C; the deformation in the width direction is 17%, and the compression temperature in the width direction is -50°C; the deformation in the thickness direction is 11%, and the compression temperature in the thickness direction is 170°C; In Comparative Example 4, the deformation in the longitudinal direction is 8%, and the compression temperature in the longitudinal direction is room temperature; the deformation in the width direction is 10%, and the compression temperature in the width direction is room temperature; the deformation in the thickness direction is 8%, and the compression temperature in the thickness direction is room temperature; In Comparative Example 5, the deformation in the longitudinal direction was 5%, the compression temperature in the longitudinal direction was 250°C, the deformation in the width direction was 10%, the compression temperature in the width direction was -50°C, the deformation in the thickness direction was 4%, and the compression temperature in the thickness direction was 110°C; In Comparative Example 6, the deformation in the longitudinal direction is 20%, the compression temperature in the longitudinal direction is 200°C, the deformation in the width direction is 10%, the compression temperature in the width direction is -50°C, the deformation in the thickness direction is 5%, and the compression temperature in the thickness direction is 170°C.

[0039] Experimental results: (1) Tensile properties: See Table 1 below for details.

[0040] Table 1 Tensile strength, yield strength and elongation of alloys with different compositions

[0041] (2) Grain structure Figure 1 EBSD diagram of the grain structure of the alloys after solid solution of Example 1, Comparative Example 1 and Comparative Example 5. Figure 1 The IPF plots in (ac) reveal that the recrystallized grains of all alloys are stretched along the deformation direction. The grain size in Example 1 is significantly smaller, while the grain sizes in Comparative Examples 1 and 5 are both relatively coarse, with similar differences. The grain size in Example 1 is significantly finer. This demonstrates that triaxial compression deformation can effectively promote grain refinement and recrystallization of the alloy, resulting in finer equiaxed grains.

[0042] (3) Precipitated phase The precipitation phases of the alloys of Example 1, Comparative Example 1 and Comparative Example 5 during peak aging were characterized by TEM. Figure 2 As shown in the figure, high-density nano-disk-shaped precipitates appear in the three alloys. Through electron diffraction, it can be determined that these disc-shaped precipitates are all T1 phases. The average diameter of the T1 phase in Example 1 is 41nm, while the diameters of the T1 phase in the alloys of Comparative Example 1 and Comparative Example 5 are 124nm and 56nm, respectively. This shows that the diameter of the T1 phase in Example 1 is significantly finer than that of the alloys of Comparative Example 1 and Comparative Example 5. Therefore, the variable temperature-three-axis compression deformation in Example 1 can more significantly refine the size of the precipitate phase, thereby effectively improving the strength of the alloy.

[0043] Example 2 The experimental alloy's composition is Al-1.5Cu-0.6Li-1.2Mg-1.2Ag-0.05Zr. This means that in this Al-Cu-Li alloy, Cu accounts for 1.5wt%, Li accounts for 0.6wt%, Mg accounts for 1.2wt%, Ag accounts for 1.2wt%, Zr accounts for 0.05wt%, and the balance is Al.

[0044] The alloy is prepared using 99.98% commercially pure aluminum, pure Mg, pure Li, pure Ag, and Al-Cu and Al-Zr master alloys as raw materials. The alloy is vacuum-casted. First, pure aluminum is smelted in a resistance furnace. Once the aluminum is melted, the master alloy and other pure metals are added. Degassing and slag removal are performed during the smelting process to minimize the effects of gases and inclusions on the ingot structure. Subsequently, the aluminum alloy is cast in a cylindrical water-cooled mold at 760°C to obtain an aluminum alloy ingot.

[0045] Then, a homogenization heat treatment was carried out, heating the temperature to 520℃ at a heating rate of 60℃ / h and keeping the temperature for 12h, and finally air-cooling to room temperature. 3 The homogenized samples were heated at 440°C for 30 hours, then hot-rolled from 20 mm to 8 mm in five passes, with each pass followed by a 5-minute heat-reinforcement cycle. The rolled plates were solution treated at 480°C for 6 hours and then quenched in water to room temperature.

[0046] After solution treatment for 5 minutes, three-dimensional compression deformation was carried out. The plate was compressed by 5% in the longitudinal direction at a compression temperature of 100°C. Then the plate direction was changed and the plate was compressed by 15% in the width direction at a compression temperature of -100°C. Then the plate direction was changed again and the plate was compressed by 5% in the thickness direction at a compression temperature of 120°C. After air cooling to room temperature and standing for 5 hours, the plate was subjected to artificial aging heat treatment at 155°C for 20 hours.

[0047] The aluminum-lithium alloy obtained by the method of this embodiment.

[0048] The aluminum-lithium alloy of this embodiment is used in aerospace, national defense and military industry, high-speed rail, automobiles, bicycles, pressure vessels, construction, and photovoltaic materials.

[0049] Preferably, the material includes profiles, plates and forgings.

[0050] An aerospace material is prepared from the aluminum-lithium alloy of this embodiment.

[0051] A national defense and military material is prepared from the aluminum-lithium alloy of this embodiment.

[0052] A high-iron material is prepared from the aluminum-lithium alloy of this embodiment.

[0053] An automotive material is prepared from the aluminum-lithium alloy of this embodiment.

[0054] A bicycle material is prepared from the aluminum-lithium alloy of this embodiment.

[0055] A pressure vessel material is prepared from the aluminum-lithium alloy of this embodiment.

[0056] A building material is prepared from the aluminum-lithium alloy of this embodiment.

[0057] A photovoltaic material is prepared from the aluminum-lithium alloy of this embodiment.

[0058] Example 3 The experimental alloy's composition is Al-5.5Cu-1.5Li-1.0Mg-0.8Ag-0.2Zr. This means that in this Al-Cu-Li alloy, Cu accounts for 5.5wt%, Li accounts for 1.5wt%, Mg accounts for 1.0wt%, Ag accounts for 0.8wt%, Zr accounts for 0.2wt%, and the balance is Al.

[0059] The alloy is prepared using 99.98% commercially pure aluminum, pure Mg, pure Li, pure Ag, and Al-Cu and Al-Zr master alloys as raw materials. The alloy is vacuum-casted. First, pure aluminum is smelted in a resistance furnace. Once the aluminum is melted, the master alloy and other pure metals are added. Degassing and slag removal are performed during the smelting process to minimize the effects of gases and inclusions on the ingot structure. Subsequently, the aluminum alloy is cast in a cylindrical water-cooled mold at 760°C to obtain an aluminum alloy ingot.

[0060] Then, a homogenization heat treatment was carried out, heating the temperature to 510℃ at a heating rate of 55℃ / h and keeping the temperature for 18h, and finally air-cooling to room temperature. 3 The homogenized samples were heated at 520°C for 20 hours and then hot-rolled from 20 mm to 4 mm in 15 passes, with each pass followed by a 10-minute heat-reinforcement cycle. The rolled plates were solution treated at 500°C for 10 minutes and then quenched in water to room temperature.

[0061] After solution treatment for 5 minutes, three-dimensional compression deformation was carried out. The plate was compressed by 10% in the longitudinal direction at a compression temperature of 150°C. Then the plate direction was changed and the plate was compressed by 12% in the width direction at a compression temperature of -80°C. Then the plate direction was changed again and the plate was compressed by 10% in the thickness direction at a compression temperature of 250°C. After air cooling to room temperature and standing for 12 hours, the plate was subjected to artificial aging heat treatment at 175°C for 10 hours.

[0062] The aluminum-lithium alloy obtained by the method of this embodiment.

[0063] The aluminum-lithium alloy of this embodiment is used in aerospace, national defense and military industry, high-speed rail, automobiles, bicycles, pressure vessels, construction, and photovoltaic materials.

[0064] Preferably, the material includes profiles, plates and forgings.

[0065] An aerospace material is prepared from the aluminum-lithium alloy of this embodiment.

[0066] A national defense and military material is prepared from the aluminum-lithium alloy of this embodiment.

[0067] A high-iron material is prepared from the aluminum-lithium alloy of this embodiment.

[0068] An automotive material is prepared from the aluminum-lithium alloy of this embodiment.

[0069] A bicycle material is prepared from the aluminum-lithium alloy of this embodiment.

[0070] A pressure vessel material is prepared from the aluminum-lithium alloy of this embodiment.

[0071] A building material is prepared from the aluminum-lithium alloy of this embodiment.

[0072] A photovoltaic material is prepared from the aluminum-lithium alloy of this embodiment.

[0073] It should be understood that in order to streamline the present disclosure and aid understanding of one or more of the various inventive aspects, in the above description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together into a single embodiment, figure, or description thereof. However, this disclosed method should not be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as reflected in the claims, inventive aspects lie in less than all of the features of the previously disclosed embodiments. Accordingly, the claims that follow the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of the invention.

[0074] Although the present invention has been described with respect to a limited number of embodiments, it will be apparent to those skilled in the art, having benefit of the foregoing description, that other embodiments are contemplated within the scope of the invention thus described. Furthermore, it should be noted that the language used in this specification has been selected primarily for readability and didactic purposes, rather than for the purpose of explaining or limiting the subject matter of the present invention. Consequently, many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the appended claims. The disclosure of the present invention is intended to be illustrative rather than restrictive of the scope of the invention, which is defined by the appended claims.

[0075] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for enhancing the precipitation strengthening effect of aluminum-lithium alloy based on three-dimensional compression deformation, characterized in that: The following steps are involved: S01, preparing an aluminum-lithium alloy ingot: the aluminum-lithium alloy ingot is an Al-Cu-Li series aluminum alloy; S02, subjecting the aluminum-lithium alloy ingot to a homogenization heat treatment: heating the ingot to 500-520°C at a heating rate of 50-60°C / h and keeping the temperature for 12-24 hours, and finally air-cooling the ingot to room temperature to obtain an ingot 1; S03, heating treatment: ingot 1 is heated at 440°C to 520°C for 10h to 30h to obtain ingot 2; S04, hot rolling: Ingot 2 is directly taken out of the furnace for hot rolling, and is hot rolled in 5-15 passes to a thickness of 4-8 mm. Each hot rolling pass is returned to the furnace and kept warm for at least 5 minutes to obtain plate 1; S05, solution treatment: Plate 1 is directly solution treated after hot rolling. Solution treatment process: holding temperature is 480°C~520°C, holding time is 10min~6h, then water quenching to room temperature to obtain plate 2; S06, pre-deformation: perform 5%-10% compression deformation along the length direction of plate 2 at a compression temperature of 100°C-200°C, then change the direction of plate 2 and perform 10%-15% compression deformation along the width direction of plate 2 at a compression temperature of -50°C--100°C, then change the direction of plate 2 again and perform 5%-10% compression deformation along the thickness direction at a compression temperature of 120°C-250°C to obtain plate 3; S07, Aging: After the plate is air-cooled to room temperature, it is left for 5h~12h and then artificially aged at 155℃~175℃ for 10~20h.

2. The method according to claim 1, characterized in that In Al-Cu-Li aluminum alloys, Cu element accounts for 1.5~5.5wt.%, Li element accounts for 0.6~1.5wt.%, Mg element accounts for 0.4~1.2wt.%, Ag element accounts for 0.5~1.2wt.%, Zr element accounts for 0.05~0.2wt% and the balance is Al.

3. Aluminum-lithium alloy obtained according to the method of claim 1 or 2.

4. The aluminum-lithium alloy according to claim 3, characterized in that The diameter of the T1 phase is 35-45 nm.

5. Application of the aluminum-lithium alloy according to claim 3 in aerospace, national defense and military industry, high-speed rail, automobiles, bicycles, pressure vessels, construction, and photovoltaic materials.

6. The use according to claim 5, characterized in that Materials include profiles, plates and forgings.

7. An aerospace material, characterized in that: Prepared from the aluminum-lithium alloy according to claim 3.

8. A national defense military material, characterized in that: Prepared from the aluminum-lithium alloy according to claim 3.

9. A high-speed iron material, characterized in that: Prepared from the aluminum-lithium alloy according to claim 3.

10. An automotive material, characterized in that: Prepared from the aluminum-lithium alloy according to claim 3.

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