Preparation process of a high-strength multi-layer heterogeneous structure aluminum-lithium alloy material

Abstract

The present invention discloses a preparation process for a high-strength, multi-level, heterogeneous aluminum-lithium alloy material, which belongs to the technical field of preparation of aluminum alloy hot-working materials. The high-strength, multi-level, heterogeneous aluminum-lithium alloy described in the present invention contains, by atomic percentage, 3% to 3.6% Cu, 1.2% to 1.6% Mg, 0.5% to 0.8% Li, 0.2% to 0.4% Zn, and the rest are Al elements and trace impurity elements. The preparation method of the high-strength, multi-level, heterogeneous aluminum-lithium alloy described in the present invention comprises the following steps: subjecting the cast aluminum-lithium alloy to a high-temperature solution treatment, and then subjecting it to non-insulation deformation under the action of thermal-mechanical coupling, followed by artificial pre-aging treatment, and then subjecting it to asymmetric cold rolling, and finally subjecting it to artificial aging treatment to obtain the high-strength, multi-level, heterogeneous aluminum-lithium alloy material. The high-strength, multi-level, heterogeneous aluminum-lithium alloy material of the present invention has the characteristics of high strength, high hardness and excellent mechanical properties.

Description

Technical Field

[0001] The invention relates to a preparation process of a high-strength multi-level heterogeneous structure aluminum-lithium alloy material, belonging to the technical field of aluminum alloy hot-working material preparation. Background Art

[0002] Aluminum-lithium alloy is a lightweight, high-strength, high-rigidity metal material with excellent mechanical properties and corrosion resistance. It is currently widely used in the fields of aerospace, automobile manufacturing, high-speed trains and electronic equipment manufacturing. As the current industry's requirements for lightweight, high-strength aluminum-lithium alloys continue to increase, research on methods to improve the strength of aluminum-lithium alloys is of great significance. This article starts from the perspective of controlling material properties through microstructure, and uses a thermal-mechanical coupling method to gradually induce the aluminum-lithium alloy material to form different microstructures, thereby preparing a high-strength aluminum-lithium alloy with a multi-level heterogeneous structure. This heterogeneous structure not only shows its excellent properties in high strength and high stiffness, but also has good resistance to cyclic fatigue loads. Therefore, aluminum-lithium alloys with multi-level heterogeneous structures have broad application prospects.

[0003] Chinese invention patent CN 116162872A discloses a method for obtaining a multi-level heterogeneous strengthening structure. The invention utilizes a process of solid solution treatment, rapid heating, large deformation, and aging to obtain a uniform solid solution structure through solid solution treatment of an aluminum alloy billet. Rapid heating and large deformation are then performed to obtain an unsteady structure composed of unstable precipitates and dislocation substructures. Aging treatment is then performed to form a multi-level heterogeneous strengthening structure with precipitates of different sizes and the coexistence of coarse and fine grains. The resulting multi-level heterogeneous strengthening structure improves the mechanical properties of the aluminum alloy, such as hardness and strength.

[0004] Chinese invention patent CN 116732455A discloses a heat treatment process for reducing the fatigue crack growth rate of aluminum-copper-magnesium alloys. The aluminum alloy sample is solution-treated and held, then rapidly hot-rolled. After hot-rolling, it is immediately cryogenically quenched. The sample obtained in step one is pre-aged with appropriate parameters. The sample obtained in step two is cryogenically deformed to obtain a cryogenically deformed sample. The cryogenically deformed sample obtained in step three is then aged to obtain the finished product. The aluminum alloy prepared by this process is simple and controllable, and the resulting product exhibits excellent performance, combining an ultra-low fatigue crack growth rate with superior mechanical strength.

[0005] However, the existing technology still has the following problems. Although the aforementioned patent CN 116162872A introduces a strengthening phase with a coarse-fine grain heterostructure, the strengthening strength is limited. In the aforementioned patent CN 116732455A, the hot rolling treatment method is introduced, resulting in a large residual stress in the obtained material. Moreover, in a high temperature environment, it is easy to cause oxidation and defects on the surface of the material, reducing the service life of the material. In summary, this paper introduces a cluster structure to make the heterostructure more complex, significantly improving the mechanical properties, and adopts a pre-aging + asymmetric cold rolling method to reduce the residual stress within the material and reduce the risk of cracking. Summary of the Invention

[0006] In order to solve the problems existing in the prior art, the present invention provides a preparation process of a high-strength multi-level heterogeneous structure aluminum-lithium alloy material, the specific steps of which are as follows:

[0007] (1) Cu, Mg, Li, Zn and Al are smelted and cast with other elements (the smelting and casting in this step can be carried out by conventional methods without special requirements) to form an aluminum-lithium alloy ingot.

[0008] (2) Solution treatment: The lithium alloy ingot obtained in step (1) is heated to the solution temperature, kept warm, and then quenched in cold water to obtain a solid solution state tissue blank.

[0009] (3) Thermal-mechanical coupling deformation: The solid solution structure blank obtained in step (2) is rapidly heated and immediately compressed and deformed without heat preservation. After the deformation is completed, it is placed in cold water for rapid cooling.

[0010] (4) Artificial pre-aging treatment: The sample treated in step (3) is placed in a heating furnace, kept warm, and then air-cooled to form precipitates of different sizes.

[0011] (5) Asymmetric cold rolling: The sample treated in step (4) is subjected to asymmetric cold rolling, with a total reduction of 50%-60%, less than 10 cold rolling passes, and a reduction of not less than 5% in each pass.

[0012] (6) Artificial aging treatment: artificial aging is performed on the sample treated in step (5).

[0013] Preferably, in step (1), the total mass percentage of Cu, Mg, Li, Zn and Al and other elements is 100%, of which Cu is 3% to 3.6%, Mg is 1.2% to 1.6%, Li is 0.5% to 0.8%, Zn is 0.2% to 0.4%, and the remainder is Al and trace impurity elements.

[0014] Preferably, in step (2), the solution temperature is 520° C.-540° C. and the temperature is kept for 1 h to 1.5 h so that the solution structure is evenly distributed in the material.

[0015] Preferably, after the solutionization in step (2) is completed, the product is immediately placed in cold water for quenching treatment, the water temperature is 20-25° C., and the quenching time is 2-3 minutes.

[0016] Preferably, in step (3), the heating rate is 360°C to 400°C / min, and the temperature is raised to 380°C to 420°C, and the instant compression deformation is 50%.

[0017] Preferably, the temperature of the heating furnace in step (4) is 120° C.-150° C., and the insulation time is 10 h to 12 h.

[0018] Preferably, in the asymmetric cold rolling in step (5), the total pressing amount is 50%-60%, the number of cold rolling passes is less than 10 times, and the pressing amount of each pass is not less than 5%.

[0019] Preferably, the rotation rate ratio of the upper and lower rollers in step (5) is 1.3, which increases the number of crystal defects and increases the generation of clusters in the subsequent artificial aging process.

[0020] Preferably, the aging temperature in step (6) is selected to be 120° C. to 150° C., and the holding time is 12 h to 14 h.

[0021] In the present invention, thermal-mechanical coupled deformation is adopted, which can reduce the deformation resistance of the material and increase the degree of deformation compared with ordinary cold deformation. At the same time, heating reduces a certain amount of internal stress and reduces the risk of material cracking. Non-steady-state heating deformation can better preserve the strengthening structure of the solid solution process. Asymmetric asynchronous rolling is adopted. Compared with ordinary cold rolling, asymmetric rolling introduces rollers with different rotation speeds, which makes the stress distribution of the metal material during the rolling process uneven. In areas of stress concentration, metal materials are prone to local plastic deformation, thereby forming vacancies. The main formation mode of clusters is the combination of vacancies and solute atoms. The increase in the number of vacancies improves the formation of clusters.

[0022] Beneficial effects of the present invention

[0023] (1) The present invention obtains a high-strength aluminum-lithium alloy with a multi-level heterogeneous reinforcement structure of different-sized precipitates, fine grains, coarse grains, clusters, etc. through processes such as high-temperature solid solution, thermal-mechanical coupled deformation, and asymmetric rolling.

[0024] (2) Compared with conventional heterogeneous structure strengthening, the production process of artificial pre-aging and asymmetric cold rolling is adopted to introduce more vacancies and form clusters, a strengthening structure composed of multiple atoms, which improves the mechanical properties of aluminum-lithium alloy such as strength and fatigue resistance.

[0025] (3) This production process has the advantages of simple operation, low cost, and easy implementation. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a flow chart of the present invention;

[0027] Figure 2 This is a schematic diagram of the production process of the high-strength multi-level heterogeneous structure aluminum-lithium alloy of the present invention. DETAILED DESCRIPTION

[0028] The present invention will be further described in detail below with reference to specific embodiments, but the protection scope of the present invention is not limited to the contents described above.

[0029] Example 1

[0030] A method for preparing a high-strength multi-layer heterostructure aluminum-lithium alloy. The chemical composition of the high-strength multi-layer heterostructure aluminum-lithium alloy implemented in the present invention is shown in Table 1.

[0031] Table 1 Chemical composition of aluminum-lithium alloy according to a specific embodiment of the present invention

[0032] Cu Mg Li Zn margin 3.125％ 1.432％ 0.514％ 0.321％ Al and other impurity elements

[0033] The specific preparation steps are as follows:

[0034] (1) According to the composition in Table 1, various elements are first smelted and cast to form an aluminum alloy ingot with a size of 50 mm × 50 mm × 10 mm.

[0035] (2) The aluminum alloy ingot obtained in step (1) is heated to 540° C. for 1 hour of high-temperature solution treatment to obtain a continuous static recrystallized solution structure, and then placed in 25° C. cold water for quenching for 3 minutes to obtain a solution structure blank.

[0036] (3) The solid solution structure blank obtained in step (2) is subjected to thermal-mechanical coupling deformation on a thermal simulation test machine, the blank is rapidly heated to 380°C at a heating rate of not less than 360°C / min, and is immediately compressed without heat preservation, with an immediate compression amount of not less than 50%, and is placed in cold water for rapid cooling to preserve the structure of the sample obtained by the thermal-mechanical coupling deformation.

[0037] (4) The sample treated in step (3) is placed in a heating furnace at 120° C. for pre-aging treatment for 10 h, and then air-cooled to obtain a first-level heterogeneous structure in which precipitates of different sizes coexist with fine grains and coarse grains.

[0038] (5) The sample processed in step (4) is subjected to asymmetric rolling treatment, with a total pressure reduction of 50%, less than 10 cold rolling passes and a pressure reduction of not less than 5% in each pass, and a rotational speed ratio of the upper and lower rollers of 1.3.

[0039] (6) The sample treated in step (5) is artificially aged by placing the sample in a heating furnace at 120° C. and keeping the temperature for 12 h to obtain a large number of cluster structures, thereby obtaining a high-strength aluminum-lithium alloy having a multi-level heterogeneous reinforcement structure with clusters, precipitated phases of different sizes, and coexistence of fine grains and coarse grains.

[0040] Example 2

[0041] A method for preparing a high-strength multi-layer heterostructure aluminum-lithium alloy. The chemical composition of a high-strength multi-layer heterostructure aluminum-lithium alloy implemented in the present invention is shown in Table 2.

[0042] Table 2 Chemical composition of aluminum-lithium alloy according to a specific embodiment of the present invention

[0043] Cu Mg Li Zn margin 3.012％ 1.592％ 0.504％ 0.201％ Al and other impurities

[0044] The specific preparation steps are as follows:

[0045] (1) According to the composition in Table 1, various elements are first smelted and cast to form an aluminum alloy ingot with a size of 50 mm × 50 mm × 10 mm.

[0046] (2) The aluminum alloy ingot obtained in step (1) is heated to 520° C. for 1 hour of high-temperature solution treatment to obtain a continuous static recrystallized solution structure, and then placed in 20° C. cold water quenching for 2 minutes to obtain a solution structure blank.

[0047] (3) The solid solution structure blank obtained in step (2) is subjected to thermal-mechanical coupling deformation on a thermal simulation test machine, the blank is rapidly heated to 400°C at a heating rate of not less than 360°C / min, and is immediately compressed without heat preservation, with an immediate compression amount of not less than 50%, and is placed in cold water for rapid cooling to preserve the structure of the sample obtained by the thermal-mechanical coupling deformation.

[0048] (4) The sample treated in step (3) is placed in a heating furnace at 150° C. for pre-aging treatment for 10 h, and then air-cooled to obtain a first-level heterogeneous structure in which precipitates of different sizes coexist with fine grains and coarse grains.

[0049] (5) The sample processed in step (4) is subjected to asymmetric rolling treatment, with a total pressure reduction of 60%, less than 10 cold rolling passes and a pressure reduction of not less than 5% in each pass, and a rotational speed ratio of the upper and lower rollers of 1.3.

[0050] (6) The sample treated in step (5) is artificially aged by placing the sample in a heating furnace at 150° C. and keeping the temperature for 12 h to obtain a large number of cluster structures, thereby obtaining a high-strength aluminum-lithium alloy having a multi-level heterogeneous reinforcement structure with clusters, precipitates of different sizes, and coexistence of fine grains and coarse grains.

[0051] Example 3

[0052] A method for preparing a high-strength multi-layer heterostructure aluminum-lithium alloy. The chemical composition of a high-strength multi-layer heterostructure aluminum-lithium alloy implemented in the present invention is shown in Table 3.

[0053] Table 3 Chemical composition of aluminum-lithium alloy according to the specific embodiment of the present invention

[0054] Cu Mg Li Zn margin 3.592％ 1.212％ 0.794％ 0.398％ Al and other impurities

[0055] The specific preparation steps are as follows:

[0056] (1) According to the composition in Table 1, various elements are first smelted and cast to form an aluminum alloy ingot with a size of 50 mm × 50 mm × 10 mm.

[0057] (2) The aluminum alloy ingot obtained in step (1) is heated to 540° C. and subjected to high-temperature solution treatment for 1.5 hours to obtain a continuous static recrystallized solution structure, and then placed in 25° C. cold water for quenching for 2 minutes to obtain a solution structure blank.

[0058] (3) The solid solution structure blank obtained in step (2) is subjected to thermal-mechanical coupling deformation on a thermal simulation test machine, the blank is rapidly heated to 380°C at a heating rate of not less than 400°C / min, and is immediately compressed without heat preservation, with an immediate compression amount of not less than 50%, and is placed in cold water for rapid cooling to preserve the structure of the sample obtained by the thermal-mechanical coupling deformation.

[0059] (4) The sample treated in step (3) is placed in a heating furnace at 120° C. for pre-aging treatment for 12 h, and then air-cooled to obtain a first-level heterogeneous structure in which precipitates of different sizes coexist with fine grains and coarse grains.

[0060] (5) The sample processed in step (4) is subjected to asymmetric rolling treatment, with the total amount of downward pressure not less than 50%, the number of cold rolling passes being less than 10 and the downward pressure of each pass being not less than 5%, and the speed ratio of the upper and lower rollers being 1.3.

[0061] (6) The sample treated in step (5) is artificially aged by placing the sample in a heating furnace at 140° C. and keeping the temperature for 14 h to obtain a large number of cluster structures, thereby obtaining a high-strength aluminum-lithium alloy having a multi-level heterogeneous reinforcement structure with clusters, precipitates of different sizes, and coexistence of fine grains and coarse grains.

[0062] Comparative Example 1

[0063] A method for preparing a high-strength multi-layer heterostructure aluminum-lithium alloy. The chemical composition of the high-strength multi-layer heterostructure aluminum-lithium alloy in this embodiment is the same as that in Example 1, as shown in Table 1.

[0064] The specific preparation steps are as follows:

[0065] (1) According to the composition in Table 1, various elements are first smelted and cast to form an aluminum alloy ingot with a size of 50 mm × 50 mm × 10 mm.

[0066] (2) The aluminum alloy ingot obtained in step (1) is heated to 540° C. for 1 hour of high-temperature solution treatment to obtain a continuous static recrystallized solution structure, and then placed in cold water for quenching treatment to obtain a solution structure blank.

[0067] (3) Next, the obtained solid solution tissue blank is subjected to thermal-mechanical coupling deformation on a thermal simulation test machine. The blank is rapidly heated to 380°C at a heating rate of not less than 360°C / min, and is subjected to immediate compression deformation without heat preservation, with an immediate compression amount of not less than 50%. It is then placed in cold water for rapid cooling to preserve the structure of the sample obtained by the thermal-mechanical coupling deformation.

[0068] (4) The sample treated in step (3) is placed in a heating furnace at 120° C. for pre-aging treatment for 10 h, and then air-cooled to obtain a first-level heterogeneous structure in which precipitates of different sizes coexist with fine grains and coarse grains.

[0069] (5) The sample processed in step (4) is cold rolled, with the total amount of reduction being not less than 50%, and the reduction in each pass being not less than 5%.

[0070] (6) The sample treated in step (5) is artificially aged by placing the sample in a heating furnace at 100° C. and keeping the temperature for 12 h to obtain a large number of cluster structures, thereby obtaining a high-strength aluminum-lithium alloy having a multi-level heterogeneous reinforcement structure with clusters, precipitates of different sizes, and coexistence of fine grains and coarse grains.

[0071] Comparative Example 2

[0072] A method for preparing a high-strength multi-layer heterostructure aluminum-lithium alloy. The chemical composition of the high-strength multi-layer heterostructure aluminum-lithium alloy in this embodiment is the same as that in Example 1, as shown in Table 1.

[0073] The specific preparation steps are as follows:

[0074] (1) According to the composition in Table 1, various elements are first smelted and cast to form an aluminum alloy ingot with a size of 50 mm × 50 mm × 10 mm.

[0075] (2) The aluminum alloy ingot obtained in step (1) is heated to 540° C. for 1 hour of high-temperature solution treatment to obtain a continuous static recrystallized solution structure, and then placed in cold water for quenching treatment to obtain a solution structure blank.

[0076] (3) The solid solution structure blank obtained in step (2) is subjected to heat preservation deformation treatment on a thermal simulation test machine, and the blank is rapidly heated to 380°C at a heating rate of not less than 360°C / min, and the sample temperature is maintained for compression deformation treatment, with the compression deformation amount not less than 50%. It is placed in cold water for rapid cooling, and the structure of the sample is obtained after preservation of the deformation.

[0077] (4) The sample treated in step (3) is placed in a heating furnace at 120° C. for pre-aging treatment for 10 h, and then air-cooled to obtain a first-level heterogeneous structure in which precipitates of different sizes coexist with fine grains and coarse grains.

[0078] (5) The sample processed in step (4) is subjected to asymmetric cold rolling, with the total amount of downward pressure not less than 50%, the number of cold rolling passes being less than 10 and the downward pressure of each pass being not less than 5%, and the upper and lower roller speed ratio being 1.3.

[0079] (6) The sample treated in step (5) is artificially aged by placing the sample in a heating furnace at 100° C. and keeping the temperature for 12 h to obtain a large number of cluster structures, thereby obtaining a high-strength aluminum-lithium alloy having a multi-level heterogeneous reinforcement structure with clusters, precipitates of different sizes, and coexistence of fine grains and coarse grains.

[0080] Comparative Example 3

[0081] A preparation method of a high-strength multi-layer heterostructure aluminum-lithium alloy specifically includes the following steps: The chemical composition of the high-strength multi-layer heterostructure aluminum-lithium alloy in this embodiment is the same as that in Example 1, as shown in Table 1.

[0082] The specific preparation steps are as follows:

[0083] (1) According to the composition in Table 1, various elements are first smelted and cast to form an aluminum alloy ingot with a size of 50 mm × 50 mm × 10 mm.

[0084] (2) The aluminum alloy ingot obtained in step (1) is heated to 540° C. for 1 hour of high-temperature solution treatment to obtain a continuous static recrystallized solution structure, and then placed in cold water for quenching treatment to obtain a solution structure blank.

[0085] (3) The solid solution structure blank obtained in step (2) is subjected to heat preservation deformation treatment on a thermal simulation test machine, and the blank is rapidly heated to 380°C at a heating rate of not less than 360°C / min, and the sample temperature is maintained for compression deformation treatment, with the compression deformation amount not less than 50%. It is placed in cold water for rapid cooling, and the structure of the sample is obtained after preservation of the deformation.

[0086] (4) The sample obtained in step (3) is placed in a heating furnace at 120° C. for pre-aging treatment. The holding time is 10 h, and then air-cooled to obtain a first-level heterogeneous structure in which precipitates of different sizes coexist with fine grains and coarse grains.

[0087] (5) cold rolling the sample obtained in step (4), with the total amount of reduction being not less than 50% and the reduction in each pass being not less than 5%.

[0088] (6) The sample obtained in step (5) is artificially aged by placing the sample in a heating furnace at 100° C. and keeping the temperature for 12 h to obtain a large number of cluster structures, thereby obtaining a high-strength aluminum-lithium alloy having a multi-level heterogeneous reinforcement structure with clusters, precipitated phases of different sizes, and coexistence of fine grains and coarse grains.

[0089] According to the embodiment, a high-strength multi-level heterogeneous structure aluminum-lithium alloy was prepared, and its performance test was described:

[0090] According to the mechanical property data of high-strength multi-level heterogeneous structure aluminum-lithium alloys prepared by different processes in Table 5, it can be seen that the yield strength, tensile strength, and hardness of Example 1 are better than those of Comparative Examples 1 to 3. This is because Example 1 uses thermal-mechanical coupled deformation and an asymmetric cold rolling process. Comparative Example 1 uses thermal-mechanical coupled deformation + cold rolling, which shows that the number of clusters produced by cold rolling alone is less than that in Example 1, and the degree of strengthening is relatively low. Comparative Example 2 uses heat preservation deformation + asymmetric cold rolling. Due to the heat preservation, solute atoms undergo thermal diffusion in the matrix, which reduces the ratio of fine grains to coarse grains, and the strengthening strength is slightly lower than that of Example 1. Comparative Example 3 uses heat preservation deformation + cold rolling, which significantly reduces the number of multi-level heterogeneous structures and the strengthening strength is far lower than that of Example 1. Therefore, thermal-mechanical coupled deformation and asymmetric cold rolling can greatly improve the mechanical properties of aluminum-lithium alloys.

[0091] Table 5 Mechanical properties of high-strength multi-level heterogeneous structure aluminum-lithium alloys of Example 1 and Comparative Examples 1-3

[0092] Sample number Yield strength / MPa Tensile strength / MPa Sample hardness / HV Example 1 446.3 550.7 247 Example 2 439.5 538.6 241 Example 3 447.1 546.3 243 Comparative Example 1 422.6 521.4 221 Comparative Example 2 419.6 527.8 213 Comparative Example 3 398.8 492.5 205

[0093] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A process for preparing a high-strength multi-level heterogeneous structure aluminum-lithium alloy material, characterized by: A multi-layered heterogeneous structure is formed by heat treatment, and the processing steps are as follows: (1) Smelting and casting Cu, Mg, Li, Zn and Al with other elements to form an aluminum-lithium alloy ingot; (2) Solution treatment: heating the lithium alloy ingot obtained in step (1) to the solution temperature, keeping the temperature, and then quenching it in cold water to obtain a solid solution state blank; (3) Thermal-mechanical coupling deformation: The solid solution state tissue blank obtained in step (2) is rapidly heated, and immediately compressed and deformed without heat preservation. After the deformation is completed, it is placed in cold water for rapid cooling; (4) Artificial pre-aging treatment: Place the sample treated in step (3) in a heating furnace, keep it warm, and then air-cool it; (5) Asymmetric cold rolling: the sample treated in step (4) is subjected to asymmetric cold rolling; (6) Artificial aging treatment: artificial aging is performed on the sample treated in step (5); In step (1), the total mass percentage of Cu, Mg, Li, Zn and Al and other elements is 100%, of which Cu is 3% to 3.6%, Mg is 1.2% to 1.6%, Li is 0.5% to 0.8%, Zn is 0.2% to 0.4%, and the remainder is Al element and trace impurity elements.

2. The process for preparing the high-strength multi-level heterogeneous aluminum-lithium alloy material according to claim 1, characterized in that: In step (2), the solution temperature is 520°C-540°C, and the temperature is kept for 1h~1.5h.

3. The process for preparing the high-strength multi-level heterogeneous aluminum-lithium alloy material according to claim 1, characterized in that: After the solution treatment in step (2) is completed, the product is immediately placed in cold water for quenching treatment. The water temperature is 20-25°C and the quenching time is 2-3 minutes.

4. The process for preparing the high-strength multi-level heterogeneous aluminum-lithium alloy material according to claim 1, characterized in that: In step (3), the heating rate is 360°C~400°C / min, and when the temperature is raised to 380°C~400°C, the instantaneous compression deformation is not less than 50%.

5. The process for preparing the high-strength multi-level heterogeneous structure aluminum-lithium alloy material according to claim 1, characterized in that: In step (4), the temperature of the heating furnace is 120°C-150°C, and the insulation time is 10h~12h.

6. The process for preparing the high-strength multi-level heterogeneous structure aluminum-lithium alloy material according to claim 1, characterized in that: In step (5), the asymmetric cold rolling is performed with a total reduction of 50%-60%, the number of cold rolling passes is less than 10, and the reduction of each pass is not less than 5%.

7. The process for preparing the high-strength multi-level heterogeneous structure aluminum-lithium alloy material according to claim 1, characterized in that: The rotation rate ratio of the upper and lower rollers in step (5) is 1.

3.

8. The process for preparing the high-strength multi-level heterogeneous structure aluminum-lithium alloy material according to claim 1, characterized in that: In step (6), the aging temperature is selected to be 120°C~150°C, and the holding time is 12h~14h.

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