Ultralow-temperature forming device and method for low-residual-stress aluminum alloy thin-wall component

Abstract

The invention provides an ultralow-temperature forming device and method for a low-residual-stress aluminum alloy thin-wall component, and the method comprises the following steps: forming an aluminum alloy plate under an ultralow-temperature condition to obtain an aluminum alloy part, then keeping a mold closing state, quickly emptying an ultralow-temperature medium in an environment box, injecting a thermal medium, and finally forming the aluminum alloy part. The environment temperature is rapidly increased to the level lower than the aging temperature from the ultralow temperature, after the temperature is homogenized through temporary heat preservation, a heat medium is discharged, the aluminum alloy part and the mold are cooled to the room temperature, and finally unloading is conducted; the method has the beneficial effects that the temperature of the mold and the aluminum alloy part in the mold closing state is rapidly increased from the ultralow temperature, temporary heat preservation and cooling treatment are carried out, the difference of the thermal expansion coefficients of the steel mold and the aluminum alloy part is utilized, and tiny and uniform plastic deformation of a blank occurs in the heating-heat preservation-cooling process; and therefore, the residual stress after ultralow-temperature forming is more uniform, and the risk of springback of the part after unloading is obviously reduced.

Description

Technical Field

[0001] The invention relates to the technical field of metal sheet forming, and in particular to an ultra-low temperature forming device and method for low residual stress aluminum alloy thin-walled components. Background Art

[0002] Aluminum alloys have high specific strength and specific stiffness, and are important lightweight materials in the fields of aerospace, automobiles, etc. They are widely used to manufacture lightweight, high-strength, thin-walled components such as rocket fuel tanks, aircraft skins, and automobile anti-collision beams. Aluminum alloys have limited plastic deformation capabilities at room temperature, and it is difficult to meet the dual requirements of material strength and plastic deformation capabilities for complex-shaped thin-walled components. In recent years, studies have found that under ultra-low temperature conditions, aluminum alloys exhibit a "double-increase effect" in which both the elongation and hardening index are greatly improved. The ultra-low temperature forming technology developed based on this can improve the forming limit and strength of aluminum alloys, and is a plastic forming technology for aluminum alloys with great application prospects.

[0003] In the plastic forming of aluminum alloy thin-walled parts, the deformation of the material is unevenly distributed due to the difference in shape at different positions. This uneven deformation leads to residual stress inside the part. After unloading, the part will produce a certain amount of springback, affecting the shape accuracy of the final part. In ultra-low temperature forming, aluminum alloy has a higher deformation resistance, which makes the risk of residual stress-induced part deformation more significant. At present, research on ultra-low temperature forming mainly focuses on the mechanism and process itself, and there is still a lack of a process route that combines ultra-low temperature forming with low residual stress manufacturing. Summary of the invention

[0004] In view of the shortcomings of the prior art mentioned above, the purpose of the present invention is to provide an ultra-low temperature forming device and method for low residual stress aluminum alloy thin-walled components, so as to solve the problem that in the existing ultra-low temperature forming technology, aluminum alloy has a higher deformation resistance, making the risk of residual stress-induced part deformation more significant.

[0005] In order to achieve the above-mentioned purpose and other related purposes, the present invention provides the following technical solutions:

[0006] A device for ultra-low temperature forming of low residual stress aluminum alloy thin-walled components comprises an environmental box, wherein a bending die is provided on the inner bottom side of the environmental box, a bending punch located in the environmental box is provided above the bending die, a solid solution aluminum alloy plate to be formed may be provided between the bending die and the bending punch, a pressure rod is provided at the top end of the bending punch, the top end of the pressure rod passes through the environmental box and extends to the outside of the environmental box, a heat medium injection port and a heat medium discharge port are provided at the bottom end of the environmental box, a heat medium injection pipe is installed at the heat medium injection port, and a heat medium discharge pipe is installed at the heat medium discharge port.

[0007] In one embodiment of the present invention, a cooling medium injection port and a cooling medium discharge port are further provided at the bottom end of the environmental box. A cooling medium injection pipe is installed at the cooling medium injection port, and a cooling medium discharge pipe is installed at the cooling medium discharge port. The cooling medium injection pipe in this technical solution can inject the cooling medium into the environmental box, and the cooling medium discharge pipe can discharge the cooling medium from the environmental box.

[0008] A method for ultra-low temperature forming of a low residual stress aluminum alloy thin-walled component, based on an ultra-low temperature forming device for the low residual stress aluminum alloy thin-walled component, comprises the following steps: treating an aluminum alloy plate to obtain a solid solution aluminum alloy plate according to the treatment result; placing the solid solution aluminum alloy plate and a forming mold into an environmental box, introducing an ultra-low temperature medium from a cooling medium injection port, cooling and keeping the solid solution aluminum alloy plate and the mold warm, so that the solid solution aluminum alloy plate and the mold are completely cooled to the temperature of the ultra-low temperature medium; then pressurizing a bending punch to complete the ultra-low temperature forming of the aluminum alloy material, thereby obtaining an aluminum alloy part, and maintaining a mold closing state;

[0009] Keep the mold in the closed state, open the cooling medium outlet, and quickly discharge the ultra-low temperature medium; then introduce hot medium from the hot medium injection port to quickly increase the temperature of the mold and aluminum alloy parts and keep them warm, so that the aluminum alloy parts and the mold are completely heated to the hot medium temperature; continue to keep the mold in the closed state, open the hot medium outlet, and discharge the hot medium; then open the environmental box, and after the aluminum alloy parts and molds are air-cooled to room temperature, open the mold for unloading and take out the aluminum alloy parts.

[0010] In one embodiment of the present invention, the processing of the aluminum alloy plate to obtain a solid solution aluminum alloy plate according to the processing result includes: performing solid solution and quenching treatment on the aluminum alloy plate to obtain a solid solution aluminum alloy plate according to the results of the solid solution and quenching treatment.

[0011] In one embodiment of the present invention, after the aluminum alloy plate is subjected to solution and quenching treatment to obtain a solid solution aluminum alloy plate according to the results of the solution and quenching treatment, the solid solution aluminum alloy plate can also be stored and transferred in a low-temperature freezing environment.

[0012] In one embodiment of the present invention, the aluminum alloy plate is subjected to a solution treatment and a quenching treatment, a solution aluminum alloy plate is obtained according to the results of the solution treatment and the quenching treatment, and the solution aluminum alloy plate is placed in a low-temperature freezing environment for storage and transfer, comprising: heating a heat treatment furnace to 520°C, placing a 6061 aluminum alloy sample in the furnace and keeping it warm for 1 hour, then taking it out and performing room temperature water-cooling quenching to obtain a solution 6061 aluminum alloy plate, and placing the solution 6061 aluminum alloy plate in a low-temperature freezing environment (about -20°C) for storage and transfer, wherein the aluminum alloy plate is a 3 mm thick 6061 aluminum alloy sample.

[0013] In one embodiment of the present invention, the solid solution aluminum alloy plate and the forming mold are placed in an environmental box, the ultra-low temperature medium introduced from the cooling medium injection port is liquid nitrogen, and then the solid solution aluminum alloy plate and the mold are cooled, and then immersed in liquid nitrogen for 15 minutes to completely cool the solid solution aluminum alloy plate and the mold to the liquid nitrogen temperature (-196°C).

[0014] In one embodiment of the present invention, the heat medium introduced from the heat medium injection port is boiling water, which causes the temperature of the mold and the aluminum alloy part to rise rapidly, and keeps the aluminum alloy part and the mold immersed in boiling water for 15 minutes so that they are fully heated to the boiling water temperature (100°C).

[0015] As described above, the ultra-low temperature forming device and method of a low residual stress aluminum alloy thin-walled component of the present invention have the following beneficial effects: the aluminum alloy plate in the present invention is first formed under ultra-low temperature conditions to obtain an aluminum alloy part, and then the mold state is maintained, the ultra-low temperature medium in the environmental box is quickly emptied, and the heat medium is injected to quickly raise the ambient temperature from the ultra-low temperature to a level lower than the aging temperature. After a short period of insulation to uniformize the temperature, the heat medium is discharged, and the aluminum alloy part and the mold are cooled to room temperature, and finally unloaded and the aluminum alloy part is taken out; therefore, the present invention rapidly heats the mold and aluminum alloy parts in the mold closing state from an ultra-low temperature, and performs a short insulation and cooling treatment, and utilizes the difference in thermal expansion coefficients between the steel mold and the aluminum alloy part to cause the blank to undergo small and uniform plastic deformation during the heating-insulation-cooling process, thereby making the residual stress after ultra-low temperature forming more uniform, and significantly reducing the risk of part rebound after unloading. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a right front view schematic diagram of an ultra-low temperature forming device for a low residual stress aluminum alloy thin-walled component disclosed in an embodiment of the present invention;

[0017] Figure 2 It is a schematic diagram of a front bottom view of an ultra-low temperature forming device for a low residual stress aluminum alloy thin-walled component disclosed in an embodiment of the present invention;

[0018] Figure 3 Shown is a three-dimensional schematic diagram of a bending die and a bending punch in an ultra-low temperature forming device for a low residual stress aluminum alloy thin-walled component disclosed in an embodiment of the present invention;

[0019] Figure 4 It is a schematic diagram showing the overall process of the ultra-low temperature forming method of a low residual stress aluminum alloy thin-walled component disclosed in an embodiment of the present invention;

[0020] Figure 5It is a schematic diagram showing the overall process route of the ultra-low temperature forming method of a low residual stress aluminum alloy thin-walled component disclosed in an embodiment of the present invention;

[0021] Figure 6 It is a schematic diagram of a finite element simulation model of a bending die, a bending punch and a solid solution aluminum alloy plate in the ultra-low temperature forming method of a low residual stress aluminum alloy thin-walled component disclosed in an embodiment of the present invention;

[0022] Figure 7 Shown is a schematic diagram of temperature changes of parts and molds in the ultra-low temperature forming method of a low residual stress aluminum alloy thin-walled component disclosed in an embodiment of the present invention;

[0023] Figure 8 It is a schematic diagram showing the stress distribution of parts before and after unloading at different times in the ultra-low temperature forming method of a low residual stress aluminum alloy thin-walled component disclosed in an embodiment of the present invention;

[0024] Fig. 9 It is a schematic diagram showing the springback of parts after unloading at different times in the ultra-low temperature forming method of low residual stress aluminum alloy thin-walled components disclosed in an embodiment of the present invention.

[0025] 1. Environmental chamber; 2. Pressure rod; 3. Second through hole; 4. Cooling medium injection pipe; 5. Heat medium discharge pipe; 6. Cooling medium discharge pipe; 7. Heat medium injection pipe; 8. Bending die; 9. Bending punch; 10. Solid solution aluminum alloy plate; 11. Sliding rod; 12. First through hole. DETAILED DESCRIPTION

[0026] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0027] The first embodiment of the present invention relates to an ultra-low temperature forming device for a low residual stress aluminum alloy thin-walled component, see Figures 1 to 3, including an environmental box 1, a bending die 8 is provided on the inner bottom side of the environmental box 1, a bending punch 9 is provided above the bending die 8 and located in the environmental box 1, a solid solution aluminum alloy plate 10 to be formed can be provided between the bending die 8 and the bending punch 9, two sliding rods 11 are provided at the top of the bending die 8, and two first through holes 12 slidably connected to the sliding rods 11 are provided on the bending punch 9; a pressure rod 2 is provided at the top of the bending punch 9, and the top of the pressure rod 2 passes through the environmental box 1 and extends to the outside of the environmental box 1, wherein the environmental box 1 includes a box body and a box cover, and a second through hole 3 for the pressure rod 2 to pass through is provided on the box cover; the bending punch 9 can be moved downward by pressing the pressure rod 2, and the solid solution aluminum alloy plate 10 is deformed under the action of the bending punch 9 and the bending die 8, thereby realizing ultra-low temperature forming of aluminum alloy thin-walled components; and the movement of the bending punch 9 can be made more stable under the cooperation of the sliding rod 11 and the first through hole 12;

[0028] A heat medium injection port and a heat medium discharge port are provided at the bottom end of the environmental box 1, a heat medium injection pipe 7 is installed at the heat medium injection port, and a heat medium discharge pipe 5 is installed at the heat medium discharge port, wherein the heat medium can be injected into the environmental box 1 through the heat medium injection pipe 7, and the heat medium can be discharged from the environmental box 1 through the heat medium discharge pipe 5; a cooling medium injection port and a cooling medium discharge port are also provided at the bottom end of the environmental box 1, a cooling medium injection pipe 4 is installed at the cooling medium injection port, and a cooling medium discharge pipe 6 is installed at the cooling medium discharge port, wherein the cooling medium can be injected into the environmental box 1 through the cooling medium injection pipe 4, and the cooling medium can be discharged from the environmental box 1 through the cooling medium discharge pipe 6.

[0029] The second embodiment of the present invention relates to a method for ultra-low temperature forming of a low residual stress aluminum alloy thin-walled component, comprising the following steps: solution treatment, ultra-low temperature forming treatment, constrained heating treatment in a mold-closed state, and unloading at room temperature. Figure 4 and Figure 5 As shown, the details are as follows:

[0030] Step 101, solution treatment includes: performing solution treatment and quenching treatment on the aluminum alloy plate to obtain a solution aluminum alloy plate 10; and storing and transferring the solution aluminum alloy plate 10 in a low-temperature freezing environment.

[0031] Specifically, for 3mm thick 6061 aluminum alloy, take a square bar sample with a size of 120mm×30mm, heat the heat treatment furnace to 520℃, put the 6061 aluminum alloy sample in and keep it warm for 1h, then take it out and quench it with water cooling at room temperature; then put the solid solution 6061 aluminum alloy into a low-temperature freezing environment (about -20℃) for storage and transfer.

[0032] Step 102, the ultra-low temperature forming treatment includes: placing the solid solution aluminum alloy plate 10 and the forming mold into the environmental box 1, introducing the ultra-low temperature medium from the cooling medium injection port, cooling and keeping the solid solution aluminum alloy plate 10 and the mold warm, so that the solid solution aluminum alloy plate 10 and the mold are completely cooled to the ultra-low temperature medium temperature; then pressurizing the bending punch 9 to complete the ultra-low temperature forming of the aluminum alloy material, thereby obtaining an aluminum alloy part, and maintaining the mold closing state.

[0033] Specifically, firstly, the solid solution aluminum alloy plate 10 and the forming mold are placed in the environmental box 1, as shown in FIG. Figures 1 to 3 As shown, liquid nitrogen is introduced from the cooling medium injection port to cool the solid solution aluminum alloy plate 10 and the mold, and then immersed in liquid nitrogen for 15 minutes to completely cool the solid solution aluminum alloy plate 10 and the mold to the liquid nitrogen temperature (-196°C); then the bending punch 9 is pressurized by the pressure rod 2, and the bending die 8 is kept fixed to complete the ultra-low temperature bending of the 6061 aluminum plate, and the mold state is maintained. The mold and the sample are as shown in FIG. Figure 6 shown.

[0034] Step 103, constrained temperature rise treatment in the mold closing state: keep the mold in the mold closing state, open the cooling medium discharge port, and quickly discharge the ultra-low temperature medium; then introduce the hot medium from the hot medium injection port to quickly increase the temperature of the mold and the aluminum alloy parts and keep them warm, so that the aluminum alloy parts and the mold are completely heated to the hot medium temperature.

[0035] Specifically, keep the mold in a closed state, open the cooling medium discharge port, and quickly discharge the remaining liquid nitrogen; then, pass boiling water through the hot medium injection port to quickly raise the temperature of the mold and aluminum alloy parts, and keep the aluminum alloy parts and mold immersed in boiling water for 15 minutes to fully heat them to the boiling water temperature (100°C).

[0036] Step 104, unloading at room temperature includes: continuing to keep the mold in the mold-closed state, opening the heat medium discharge port, and discharging the heat medium; then opening the environmental box 1, and after the aluminum alloy part and the mold are air-cooled to room temperature, opening the mold for unloading and taking out the aluminum alloy part.

[0037] Specifically, the mold is kept in the closed state, the heat medium outlet is opened, and the boiling water is discharged; then the environmental box 1 is opened, and after the aluminum alloy parts and the mold are cooled to room temperature, the mold is opened for unloading (corresponding to Figure 7 At the unloading moment 1), take out the aluminum alloy parts.

[0038] Furthermore, the present invention also provides a 6061 aluminum alloy U-shaped part ultra-low temperature bending forming method, which is compared with the above-mentioned second embodiment, that is, comparative example 1, and includes the following steps: solution treatment, ultra-low temperature forming treatment, constrained heating treatment in a closed mold state, and unloading and cooling under high temperature conditions; wherein the solution treatment step is the same as the step in the above-mentioned second embodiment; the ultra-low temperature forming treatment step is the same as the step in the above-mentioned second embodiment; the constrained heating treatment step in the closed mold state is the same as the step in the above-mentioned second embodiment; the unloading and cooling step under high temperature conditions includes: a) opening the mold in a boiling water immersion state to unload (corresponding to Figure 7 unloading moment 2); b) open the heat medium discharge port to discharge the boiling water; c) open the environmental box 1, and take out the aluminum alloy parts after the aluminum alloy parts and the mold are air-cooled to room temperature.

[0039] The present invention also provides a 6061 aluminum alloy U-shaped piece ultra-low temperature bending forming method, which is compared with the above-mentioned second embodiment, that is, comparative example 2, and includes the following steps: solution treatment, ultra-low temperature forming treatment, heating treatment in an unloaded state, and cooling to room temperature; the solution treatment step is the same as the step in the above-mentioned second embodiment; the ultra-low temperature forming step is the same as the step in the above-mentioned second embodiment; the heating treatment step in the unloaded state includes: a) opening the mold in a liquid nitrogen soaked state to unload (corresponding to Figure 7 unloading moment 3); b) opening the cooling medium outlet and quickly discharging the remaining liquid nitrogen; c) introducing boiling water from the heat medium injection port to rapidly increase the temperature of the mold and the aluminum alloy part, and keeping the aluminum alloy part and the mold immersed in boiling water for 15 minutes to fully heat them to the boiling water temperature (100°C); the cooling to room temperature step includes: a) opening the heat medium outlet and discharging the boiling water; b) opening the environmental box, and taking out the aluminum alloy part after the aluminum alloy part and the mold are air-cooled to room temperature.

[0040] The above process was simulated by thermal-mechanical coupling finite element simulation. The simulation software was ABAQUS. The part material was 6061 aluminum alloy and the mold material was 4Cr5Mo2MnVSi mold steel. The stress distribution of the parts before and after unloading at three different unloading times was compared. Figure 8 As shown, the unloading rebound result is as follows Fig. 9As shown; it can be seen that under the condition of unloading immediately after ultra-low temperature forming in comparative example 2, the stress distribution of the part is uneven, the deformation of the U-shaped side wall and the fillet is large and has a large stress, the deformation of the two sides of the sample and the U-shaped bottom is small and the stress is small, and the springback angle of the part after unloading is 4.11°; in comparative example 1, since the part and the mold undergo a heating treatment and show different thermal expansion amounts, the two sides of the part and the U-shaped bottom are deformed, thereby reducing the overall stress unevenness. After unloading under high temperature, the springback angle of the part is reduced to 2.67°; in the second embodiment, the part is cooled to room temperature under a constrained state. Since the cooling shrinkage of the aluminum alloy part is greater than that of the steel mold, the part is unloaded to a certain extent, so that the residual stress reaches a lower level. At this time, the mold is opened to unload, and the springback angle of the part is only 0.25°.

[0041] In summary, compared with the traditional method of direct unloading after ultra-low temperature forming, the present invention proposes for the first time to add a constrained heating and cooling step after ultra-low temperature forming, and utilizes the different thermal expansion coefficients of the steel mold and the aluminum alloy part so that in the process of heating from the ultra-low temperature state to the high temperature, the mold undergoes a smaller thermal expansion when heated, and the aluminum alloy undergoes a larger thermal expansion when heated, so that the aluminum alloy part is squeezed as a whole during the heating process and undergoes a certain plastic deformation, thereby reducing the degree of uneven deformation of the part after forming, thereby reducing the residual stress level of the part, reducing the amount of springback of the part after unloading, and realizing ultra-low temperature forming of aluminum alloy low residual stress thin-walled components; in addition, after the part is subjected to ultra-low temperature-heating treatment, the higher temperature gradient is conducive to the uniform dispersion nucleation of the aluminum alloy strengthening phase, and at the same time, due to the low heating temperature, the ultra-low temperature forming microstructure can be preserved to the greatest extent, thereby providing excellent microstructure preparation for subsequent aging heat treatment, which is conducive to obtaining high-performance parts.

[0042] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. All equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical ideas disclosed in the present invention shall still be covered by the claims of the present invention.

Claims

1. An ultra-low temperature forming device for low residual stress aluminum alloy thin-walled components, characterized in that: The invention comprises an environmental box (1), wherein a bending die (8) is provided on the inner bottom side of the environmental box (1), a bending punch (9) located in the environmental box (1) is provided above the bending die (8), a solid solution aluminum alloy plate (10) to be formed may be provided between the bending die (8) and the bending punch (9), a pressure rod (2) is provided at the top end of the bending punch (9), the top end of the pressure rod (2) passes through the environmental box (1) and extends to the outside of the environmental box (1), a heat medium injection port and a heat medium discharge port are provided at the bottom end of the environmental box (1), a heat medium injection pipe (7) is installed at the heat medium injection port, and a heat medium discharge pipe (5) is installed at the heat medium discharge port.

2. The ultra-low temperature forming device for low residual stress aluminum alloy thin-walled components according to claim 1, characterized in that: The bottom end of the environmental box (1) is also provided with a cooling medium injection port and a cooling medium discharge port, a cooling medium injection pipe (4) is installed at the cooling medium injection port, and a cooling medium discharge pipe (6) is installed at the cooling medium discharge port.

3. A method for ultra-low temperature forming of low residual stress aluminum alloy thin-walled components, characterized in that: The ultra-low temperature forming device of the low residual stress aluminum alloy thin-walled component according to any one of claims 1 to 2 comprises the following steps: Treating the aluminum alloy plate to obtain a solid solution aluminum alloy plate (10) according to the treatment result; The solid solution aluminum alloy plate (10) and the forming mold are placed in an environmental box (1), and an ultra-low temperature medium is introduced from the cooling medium injection port to cool and keep the solid solution aluminum alloy plate (10) and the mold warm, so that the solid solution aluminum alloy plate (10) and the mold are completely cooled to the temperature of the ultra-low temperature medium; then, the bending punch (9) is pressurized to complete the ultra-low temperature forming of the aluminum alloy material, thereby obtaining an aluminum alloy part, and the mold is kept in a closed state; Keep the mold in the closed state, open the cooling medium outlet, and quickly discharge the ultra-low temperature medium; then introduce the hot medium from the hot medium injection port to quickly raise the temperature of the mold and aluminum alloy parts and keep them warm, so that the aluminum alloy parts and the mold are completely heated to the hot medium temperature; The mold is kept in the closed state, and the heat medium outlet is opened to discharge the heat medium; then the environmental box (1) is opened, and after the aluminum alloy part and the mold are air-cooled to room temperature, the mold is opened to unload and the aluminum alloy part is taken out.

4. The ultra-low temperature forming method of a low residual stress aluminum alloy thin-walled component according to claim 3, characterized in that: The step of treating the aluminum alloy plate to obtain a solid solution aluminum alloy plate (10) according to the treatment result comprises: The aluminum alloy plate is subjected to a solid solution treatment and a quenching treatment, and a solid solution aluminum alloy plate (10) is obtained according to the results of the solid solution treatment and the quenching treatment.

5. The ultra-low temperature forming method of a low residual stress aluminum alloy thin-walled component according to claim 4, characterized in that: After the aluminum alloy plate is subjected to solution and quenching treatment to obtain a solid solution aluminum alloy plate (10) according to the results of the solution and quenching treatment, the solid solution aluminum alloy plate (10) can also be placed in a low-temperature freezing environment for storage and transfer.

6. The ultra-low temperature forming method of a low residual stress aluminum alloy thin-walled component according to claim 5, characterized in that: The aluminum alloy plate is subjected to a solutionizing and quenching treatment, a solid-solution aluminum alloy plate (10) is obtained according to the results of the solutionizing and quenching treatment, and the solid-solution aluminum alloy plate (10) is placed in a low-temperature freezing environment for storage and transfer, comprising: After the heat treatment furnace is heated to 520°C, a 6061 aluminum alloy sample is placed in the heat treatment furnace and kept warm for 1 hour, then taken out and water-cooled quenched at room temperature to obtain a solid solution 6061 aluminum alloy plate, and the solid solution 6061 aluminum alloy plate is placed in a low-temperature freezing environment (about -20°C) for storage and transfer, wherein the aluminum alloy plate is a 3 mm thick 6061 aluminum alloy sample.

7. The ultra-low temperature forming method of a low residual stress aluminum alloy thin-walled component according to claim 3, characterized in that: The solid solution aluminum alloy plate (10) and the forming mold are placed in an environmental box (1), and the ultra-low temperature medium introduced from the cooling medium injection port is liquid nitrogen. The solid solution aluminum alloy plate (10) and the mold are then cooled, and then immersed in liquid nitrogen for 15 minutes to completely cool the solid solution aluminum alloy plate (10) and the mold to the liquid nitrogen temperature (-196°C).

8. The ultra-low temperature forming method of a low residual stress aluminum alloy thin-walled component according to claim 3, characterized in that: The heat medium introduced from the heat medium injection port is boiling water, which rapidly increases the temperature of the mold and the aluminum alloy part, and keeps the aluminum alloy part and the mold immersed in boiling water for 15 minutes to fully heat them to the boiling water temperature (100° C.).

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