Manufacturing method for low residual stress aluminum alloy reflector material

Abstract

A method for manufacturing a low-residual-stress aluminum alloy reflector material is provided, which can reduce the residual stress of the aluminum alloy and improve the performance of the aluminum alloy. [Solution] The treated aluminum alloy is immersed at -180 to -160°C for a certain period of time, followed by medium-low temperature annealing, with the annealing temperature being 250-300°C, to obtain a low-residual stress aluminum alloy reflector material, the immersion time being 6-10 hours, the annealing time being 3-5 hours, and the aluminum alloy being an aluminum-magnesium-silicon alloy, and the method for producing the treated aluminum alloy is characterized in that the aluminum alloy blank after homogenization treatment is subjected to medium-low temperature rolling, high temperature annealing, low temperature rolling, medium-low temperature annealing, solid solution treatment, and aging treatment.

Description

Technical Field

[0001] The present invention belongs to the technical field of non-ferrous metal material manufacturing, and specifically relates to a low residual stress aluminum alloy mirror material and a manufacturing method.

Background Art

[0002] Aluminum alloy mirrors can be manufactured by quickly processing the substrate structure of the mirror using conventional processes such as turning, milling, and grinding, fully leveraging the advantage of the easy forming of aluminum alloy materials. At the same time, by using the diamond single-point turning process to process the mirror surface, a smooth surface that meets the requirements of the imaging quality of infrared optical systems can be directly obtained, and aspherical surfaces can be processed economically and efficiently, making it favored in the field of engineering optics.

[0003] Surface shape accuracy is a point that aluminum alloy mirrors always focus on. Single-point diamond machining can directly obtain a surface shape and surface quality that meet the applications in the medium and long-wave infrared wavelength range. Ensuring the surface shape accuracy of the mirror is beneficial for the long-term maintenance of the parameters of the optical system, and is particularly suitable for optical systems with long-term stable operation.

[0004] Chinese Patent Application Publication No. 116904887 discloses a low-cost aluminum alloy mirror material and a manufacturing method, including steps of subjecting a 6-series aluminum alloy after homogenization treatment to medium and low-temperature rolling, high-temperature solid solution, low-temperature rolling, medium and low-temperature annealing, solid solution treatment, and aging treatment to obtain a low-cost aluminum alloy mirror material. This mainly reduces the surface roughness by controlling the crystal grain size.

[0005] Residual stress somewhat occurs in the aluminum alloy material during the plastic deformation and solution quenching processes, causing a problem of reduction in surface shape accuracy during the later application of the aluminum alloy mirror. Therefore, it is necessary to take strict heat treatment measures for the aluminum alloy mirror blank to remove the residual stress in the material, fully release the internal stress of the blank, and stabilize the dimensions of the blank.

[0006] Common methods for relieving residual stress include aging, mechanical drawing (TX51), die cold pressing (TX52), upward gradient quenching (TX53), die drawing (TX54), and vibration removal. Aging is a conventional method for reducing quenched residual stress. Aluminum alloy materials, especially aerospace aluminum alloys, are very sensitive to temperature. Increasing the aging temperature inevitably leads to a significant decrease in strength index, causing excessive precipitation of reinforcing phases such as MgZn2 and resulting in overaging. Therefore, post-quenching aging treatment is usually performed at relatively low temperatures, which affects the stress relief effect (only 10-35%). [Overview of the project] [Problems that the invention aims to solve]

[0007] The technical problem that this invention aims to solve is to provide a low-residual-stress aluminum alloy reflector material and a manufacturing method that reduce residual stress in aluminum alloys and improve the performance of aluminum alloys. [Means for solving the problem]

[0008] An embodiment of the present invention provides a method for manufacturing a low residual stress aluminum alloy reflector material. After processing, the aluminum alloy is immersed at -180 to -160°C for a certain period of time, followed by medium-low temperature annealing, with an annealing temperature of 200-300°C, to obtain a low residual stress aluminum alloy reflector material.

[0009] In one embodiment, the immersion time is 6-10 hours.

[0010] In one embodiment, the annealing time is 3-5 hours.

[0011] In one embodiment, the aluminum alloy is an aluminum-magnesium-silicon alloy.

[0012] In one embodiment, the method for manufacturing the treated aluminum alloy involves performing medium- and low-temperature rolling, high-temperature annealing, low-temperature rolling, medium- and low-temperature annealing, solid solution treatment, and aging treatment on the aluminum alloy blank after homogenization treatment.

[0013] In one embodiment, the medium- and low-temperature rolling method is such that the rolling temperature is 280-350°C, the total deformation of the medium- and low-temperature rolling is 85% or more, and the medium- and low-temperature large deformation is sufficient to crush and refine the second-phase particles on the order of microns.

[0014] In one embodiment, the high-temperature annealing temperature is 530-580°C, the holding time is 1-3 hours, and the high-temperature annealing dissolves the second phase particles, after crushing and refinement, into the aluminum substrate.

[0015] In one embodiment, the rolling temperature for the low-temperature rolling is 25-30°C, the deformation is 15-25%, and sufficient deformation energy storage can be obtained through low-temperature deformation.

[0016] In one embodiment, the temperature for the medium-to-low temperature annealing was 250-300°C, and the annealing time was 3-5 hours, which removed work hardening, released the deformation energy stored by significant deformation at room temperature, and reduced the driving force for static recrystallization.

[0017] In one embodiment, the temperature of the solid solution treatment was 540-560°C, and the duration was 1-2 hours.

[0018] In one embodiment, the temperature of the aging treatment is 170-180°C, and the duration is 10-16 hours.

[0019] The aluminum alloy of the present invention may be an aluminum alloy that has undergone high-temperature extrusion, high-temperature solid solution, or aging treatment before immersion.

[0020] An embodiment of the present invention provides a low residual stress aluminum alloy reflector material obtained by the above manufacturing method. [Effects of the Invention]

[0021] The beneficial effect of the present invention is that, after artificial aging of the mirror blank of an aluminum alloy reflector, a cryogenic immersion treatment is first employed to introduce new dislocations through lattice strain and lattice contraction under cryogenic conditions, and the motion of dislocations present in the reinforcing phase is shortened by the distance of motion, thereby dispersing the dislocation distribution of the mirror blank. Furthermore, existing dislocations are restored by a medium-to-low temperature annealing treatment, entangled dislocations are ordered, and residual stress is effectively reduced.

[0022] The cryogenic immersion treatment temperature in this invention is -180 to -160°C. If the temperature is lower or higher than this temperature, the residual stress of the aluminum alloy reflector material increases. The annealing temperature in this invention is 200-300°C. If the temperature is lower or higher than this temperature, the residual stress of the aluminum alloy reflector material increases. [Modes for carrying out the invention]

[0023] Example 1 A method for manufacturing a low-residual-stress Al-Mg-Si alloy mirror material includes the following steps. Step 1: Take one Al-Mg-Si alloy blank (specifically, the Al-Mg-Si alloy is 6061 aluminum alloy, and other examples and comparative examples are the same as in Example 1) in a soaked state and perform medium-to-low temperature rolling. The blank thickness is 250 mm, the rolling temperature is 300°C ± 3°C, and it is rolled down to 30 mm. The total deformation is 92%, and the pass deformation is 10-15%. Step 2: Anneal the blank from Step 1 at 580°C for 3 hours. Step 3: The blank from Step 2 is rolled at room temperature at 30°C ± 3°C until it reaches 25 mm, with a total deformation of 16.7% and a pass deformation of 3-5%. Step 4: Anneal the blank from Step 3 at 300°C for 5 hours. Step 5: The blank from Step 4 is subjected to solid solution and quenching treatments, and finally artificial aging treatments are performed to reach the T6 state. The solid solution temperature is 560°C for 2 hours, and the aging temperature is 180°C for 10 hours. Step 6: Perform cryogenic immersion on the blank obtained in Step 5. The immersion time is 10 h and the temperature is -180°C. Step 7: Anneal the blank obtained in Step 6 at medium and low temperatures. The annealing time is 3 h and the temperature is 250°C, thus completing the low residual stress Al-Mg-Si alloy mirror material.

[0024] Example 2 The manufacturing method of the low residual stress Al-Mg-Si alloy mirror material includes the following steps. Step 1: Take one Al-Mg-Si alloy blank in the soaking state and perform medium and low temperature rolling. The thickness of the blank is 250 mm, the rolling temperature is 300°C ± 3°C, roll it to 30 mm, the total deformation is 88%, and the pass deformation is 20 - 30%. Step 2: Anneal the blank obtained in Step 1 at a high temperature of 560°C for 1.5 h. Step 3: Roll the blank obtained in Step 2 at room temperature at 25°C ± 3°C and roll it to 25 mm. The total deformation is 16.7% and the pass deformation is 8 - 12%. Step 4: Anneal the blank obtained in Step 3 at medium and low temperatures at 250°C for 3 h. Step 5: Perform solution treatment and quenching on the blank obtained in Step 4, and finally make it in the T6 state through artificial aging treatment. The solution temperature is 550°C, the time is 1 h, the aging temperature is 170°C, and the time is 16 h. Step 6: Perform cryogenic immersion on the blank obtained in Step 5. The immersion time is 10 h and the temperature is -160°C. Step 7: Perform medium and low temperature annealing on the blank obtained in Step 6. The annealing time is 5 h and the temperature is 300°C, thus completing the low residual stress Al-Mg-Si alloy mirror material.

[0025] Comparative Example 1 The specific process includes the following steps. Step 1: Take one Al-Mg-Si alloy blank in the soaking state and perform medium and low temperature rolling. The thickness of the blank is 250 mm, the rolling temperature is 300°C ± 3°C, roll it to 30 mm, the total deformation is 88%, and the pass deformation is 20 - 30%. Step 2: High-temperature anneal the blank from Step 1 at 560°C for 1.5 hours. Step 3: The blank from Step 2 is rolled at room temperature at 25°C ± 3°C until it reaches 25 mm, with a total deformation of 16.7% and a pass deformation of 8-12%. Step 4: Anneal the blank from Step 3 at a moderate temperature of 250°C for 3 hours. Step 5: The blank from Step 4 is subjected to solid solution and quenching treatments, and finally artificial aging treatments are performed to reach the T6 state. The solid solution temperature is 550°C for 1 hour, the aging temperature is 170°C for 16 hours. Step 6: The blank from Step 5 is subjected to cryogenic immersion for 10 hours at a temperature of -160°C.

[0026] Comparative Example 2 The specific process includes the following steps: Step 1: Take one Al-Mg-Si alloy blank in a soaked state and perform medium-to-low temperature rolling. The blank thickness is 250 mm, the rolling temperature is 300°C ± 3°C, and it is rolled down to 30 mm. The total deformation is 88%, and the pass deformation is 20-30%. Step 2: High-temperature anneal the blank from Step 1 at 560°C for 1.5 hours. Step 3: The blank from Step 2 is rolled at room temperature at 25°C ± 3°C until it reaches 25 mm, with a total deformation of 16.7% and a pass deformation of 8-12%. Step 4: Anneal the blank from Step 3 at a moderate temperature of 250°C for 3 hours. Step 5: The blank from Step 4 is subjected to solid solution and quenching treatments, and finally artificial aging treatments are performed to reach the T6 state. The solid solution temperature is 550°C for 1 hour, the aging temperature is 170°C for 16 hours. Step 6: Perform medium-to-low temperature annealing on the blank from Step 5, with an annealing time of 5 hours and a temperature of 300°C to complete the low residual stress Al-Mg-Si alloy reflector material.

[0027] Comparative Example 3 The specific process includes the following steps: Step 1: Take one Al-Mg-Si alloy blank in a soaked state and perform medium-to-low temperature rolling. The blank thickness is 250 mm, the rolling temperature is 300°C ± 3°C, and it is rolled down to 30 mm. The total deformation is 88%, and the pass deformation is 20-30%. Step 2: High-temperature anneal the blank from Step 1 at 560°C for 1.5 hours. Step 3: The blank from Step 2 is rolled at room temperature at 25°C ± 3°C until it reaches 25 mm, with a total deformation of 16.7% and a pass deformation of 8-12%. Step 4: Anneal the blank from Step 3 at a moderate temperature of 250°C for 3 hours. Step 5: The blank from Step 4 is subjected to solid solution and quenching treatments, and finally artificial aging treatments are performed to reach the T6 state. The solid solution temperature is 550°C for 1 hour, the aging temperature is 170°C for 16 hours.

[0028] Comparative Example 4 The specific process includes the following steps: Step 1: Take one Al-Mg-Si alloy blank in a soaked state and perform high-temperature multi-directional forging. Heat the material to 460°C and adopt a multi-directional forging process of four upsettings and three drawing. Perform one upsetting and one drawing in each of the three directions of the corresponding blank: lateral, longitudinal, and height. The final upsetting is performed in the height direction, with a deformation amount of 55% per upsetting, and the final forging temperature is 320°C. Step 2: High-temperature anneal the blank from Step 1 at 560°C for 1.5 hours. Step 3: Cryogenic multi-directional forging is performed on the blank from Step 2, the forged blank is cooled to -196°C, and a three-upset, three-draw forging process is adopted, with one upset and one draw performed in each of the three directions of the forged blank: lateral, longitudinal, and height, with a deformation amount of 40% per upset. Step 4: Anneal the blank from Step 3 at a moderate temperature of 250°C for 3 hours. Step 5: The blank from Step 4 is subjected to solid solution and quenching treatments, and finally artificial aging treatments are performed to reach the T6 state. The solid solution temperature is 550°C for 1 hour, the aging temperature is 170°C for 16 hours.

[0029] Comparative Example 5 The specific process includes the following steps: Step 1: Take one Al-Mg-Si alloy blank in a soaked state and forge the blank using high-temperature multi-directional forging. Heat the blank to 460°C and employ a multi-directional forging process with four upsettings and three drawing steps. Perform one upsetting and one drawing step in each of the three directions corresponding to the blank: lateral, longitudinal, and vertical. The final upsetting is performed in the vertical direction, with a deformation amount of 55% per upsetting step and a final forging temperature of 320°C. Step 2: The blank from Step 1 is cryogenically multi-directional forged, the forged blank is cooled to -196°C, and a three-upset, three-draw forging process is adopted, with one upset and one draw performed in each of the three directions of the forged blank: lateral, longitudinal, and height, with a deformation amount of 40% per upset. Step 3: Take the blank from Step 2 and perform medium-to-low temperature rolling at a rolling temperature of 300°C ± 3°C, with a total deformation of 88% and a pass deformation of 20-30%. Step 4: High-temperature anneal the blank from Step 3 at 560°C for 1.5 hours. Step 5: The blank from Step 4 is rolled at room temperature at 25°C ± 3°C until it reaches 25 mm, with a total deformation of 16.7% and a pass deformation of 8-12%. Step 6: Anneal the blank from Step 5 at a moderate temperature of 250°C for 3 hours. Step 7: The blank from Step 6 is subjected to solid solution and quenching treatments, and finally artificial aging treatments are performed to reach the T6 state. The solid solution temperature is 550°C for 1 hour, the aging temperature is 170°C for 16 hours.

[0030] Comparative Example 6 The specific process includes the following steps: Step 1: Take one Al-Mg-Si alloy blank in a soaked state and perform medium-to-low temperature rolling. The blank thickness is 250 mm, the rolling temperature is 300°C ± 3°C, and it is rolled down to 30 mm. The total deformation is 88%, and the pass deformation is 20-30%. Step 2: High-temperature anneal the blank from Step 1 at 560°C for 1.5 hours. Step 3: The blank from Step 2 is rolled at room temperature at 25°C ± 3°C until it reaches 25 mm, with a total deformation of 16.7% and a pass deformation of 8-12%. Step 4: Anneal the blank from Step 3 at a moderate temperature of 250°C for 3 hours. Step 5: The blank from Step 3 is subjected to solid solution and quenching treatments, and finally artificial aging treatments are performed to reach the T6 state. The solid solution temperature is 550°C for 1 hour, the aging temperature is 170°C for 16 hours. Step 6: The blank from Step 5 is cryogenically multi-directional forged, the forged blank is cooled to -196°C, and a three-upset, three-draw forging process is adopted, with one upset and one draw performed in each of the three directions of the forged blank: lateral, longitudinal, and height, with a deformation amount of 10% per upset. Step 7: Perform medium-to-low temperature annealing on the blank from Step 6, with an annealing time of 5 hours and a temperature of 300°C to complete the low residual stress Al-Mg-Si alloy reflector material.

[0031] Comparative Example 7 A method for manufacturing a low-residual-stress Al-Mg-Si alloy mirror material includes the following steps. Step 1: Take one Al-Mg-Si alloy blank (specifically, the Al-Mg-Si alloy is 6061 aluminum alloy, and other examples and comparative examples are the same as in Example 1) in a soaked state and perform medium-to-low temperature rolling. The blank thickness is 250 mm, the rolling temperature is 300°C ± 3°C, and it is rolled down to 30 mm. The total deformation is 92%, and the pass deformation is 10-15%. Step 2: Anneal the blank from Step 1 at 580°C for 3 hours. Step 3: The blank from Step 2 is rolled at room temperature at 30°C ± 3°C until it reaches 25 mm, with a total deformation of 16.7% and a pass deformation of 3-5%. Step 4: Anneal the blank from Step 3 at 300°C for 5 hours. Step 5: The blank from Step 4 is subjected to solid solution and quenching treatments, and finally artificial aging treatments are performed to reach the T6 state. The solid solution temperature is 560°C for 2 hours, and the aging temperature is 180°C for 10 hours. Step 6: The blank from Step 5 is subjected to cryogenic immersion for 10 hours at a temperature of -190°C. Step 7: The blank from Step 6 is annealed at a medium-low temperature for 3 hours at a temperature of 250°C to complete the low-residual-stress Al-Mg-Si alloy reflector material.

[0032] Comparative Example 8 A method for manufacturing a low-residual-stress Al-Mg-Si alloy mirror material includes the following steps. Step 1: Take one Al-Mg-Si alloy blank (specifically, the Al-Mg-Si alloy is 6061 aluminum alloy, and other examples and comparative examples are the same as in Example 1) in a soaked state and perform medium-to-low temperature rolling. The blank thickness is 250 mm, the rolling temperature is 300°C ± 3°C, and it is rolled down to 30 mm. The total deformation is 92%, and the pass deformation is 10-15%. Step 2: Anneal the blank from Step 1 at 580°C for 3 hours. Step 3: The blank from Step 2 is rolled at room temperature at 30°C ± 3°C until it reaches 25 mm, with a total deformation of 16.7% and a pass deformation of 3-5%. Step 4: Anneal the blank from Step 3 at 300°C for 5 hours. Step 5: The blank from Step 4 is subjected to solid solution and quenching treatments, and finally artificial aging treatments are performed to reach the T6 state. The solid solution temperature is 560°C for 2 hours, and the aging temperature is 180°C for 10 hours. Step 6: The blank from Step 5 is subjected to cryogenic immersion for 10 hours at a temperature of -180°C. Step 7: The blank from Step 6 is annealed at a medium-low temperature for 3 hours at a temperature of 350°C to complete the low-residual-stress Al-Mg-Si alloy reflector material.

[0033] The aluminum alloys of each of the above examples and comparative examples were detected, their surface shape accuracy was measured, and the performance detection table in Table 1 was obtained.

[0034] JPEG0007894501000001.jpg79170

[0035] The single-point turning method of this invention is ultra-precision surface machining using a single-point diamond lathe, and the assembly method is screw fixing + hinge + adhesive bonding.

[0036] The detection methods for the single-point turning rear surface shape accuracy and the assembly rear surface shape accuracy described in this application are both three-dimensional contour methods.

[0037] Those skilled in the art should understand that the discussion of any of the embodiments described above is illustrative and not intended to imply that the scope of protection of this application is limited to these examples, and that in the spirit of this application, technical features in the embodiments described above or in different embodiments may be combined, the steps may be implemented in any order, and many other variations exist in different aspects of one or more embodiments of this application as described above, which are not provided in detail for the sake of brevity.

[0038] One or more embodiments in this Application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of this Application. Accordingly, any omissions, modifications, equivalent substitutions, improvements, etc., made without departing from the spirit and principles of one or more embodiments in this Application should be included within the scope of protection of this Application.

Claims

[Claim 1] A method for manufacturing a low residual stress aluminum alloy reflector material made of an aluminum-magnesium-silicon alloy, characterized in that, after homogenization treatment, the aluminum-magnesium-silicon alloy blank is subjected to a series of processes: medium-low rolling at a rolling temperature of 280 to 350°C, high-temperature annealing at a temperature of 530 to 580°C, low-temperature rolling at a rolling temperature of 25 to 30°C, medium-low annealing at a temperature of 250 to 300°C, solid solution treatment at a temperature of 540 to 560°C, and aging treatment at a temperature of 170 to 180°C; the aluminum-magnesium-silicon alloy after the aging treatment is immersed at -180 to -160°C for 6 to 10 hours, and then subjected to a further medium-low annealing at a temperature of 250 to 300°C for 3 to 5 hours.

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