A method for producing an optical microcrystalline aluminum alloy rod

Abstract

The application belongs to the technical field of aluminum alloy material preparation, and particularly relates to a preparation method of optical microcrystalline aluminum alloy rod material, wherein aluminum alloy ingot is sequentially subjected to high-temperature rotary swaging, high-temperature extrusion, intermediate annealing, high-temperature secondary extrusion and stabilization treatment to obtain the optical microcrystalline aluminum alloy rod material; the heating temperature of the high-temperature rotary swaging is 300-350 DEG C, the processing temperature of the high-temperature extrusion is 250-350 DEG C, the temperature of the intermediate annealing is 380-430 DEG C, and the temperature of the high-temperature secondary extrusion is 250-350 DEG C; the application simultaneously improves the hardness and reduces the surface roughness of the product.

Description

Technical Field

[0001] This invention belongs to the field of aluminum alloy material preparation technology, specifically relating to a method for preparing optical microcrystalline aluminum alloy rods. Background Technology

[0002] In recent years, with the continuous expansion of the aerospace satellite research field and the advancement of technologies such as microelectromechanical systems (MEMS) and precision manufacturing, micro- and nano-satellites have emerged. To meet the functional requirements of micro- and nano-satellites, the optical payloads they use must possess characteristics such as excellent performance, low cost, and rapid manufacturing response. Traditional optical payload systems generally use ceramic materials such as glass to manufacture optical elements, and their processing employs grinding, polishing, and shaping processes. This brings many limitations to the development of traditional optical payloads, such as difficulty in improving performance, high manufacturing costs, and long manufacturing cycles, making it difficult to meet the application requirements of micro- and nano-optical payloads.

[0003] The advantages of using aluminum alloys for optical payloads are as follows: 1. Aluminum alloys have excellent machinability and can be designed into complex optical surfaces with greater freedom, which helps to further simplify the structure of optical systems, reduce the number and size of optical components, and further improve imaging quality and enhance the performance of optical systems.

[0004] 2. Aluminum alloy materials have excellent mechanical properties and high thermal conductivity, which can realize the optomechanical integration design of optical systems, avoid the mirror distortion caused by uneven thermal expansion and contraction due to different materials of optical components and structural parts, and help maintain the optical performance of the system.

[0005] 3. Aluminum alloy materials can be rapidly processed and shaped using multi-axis ultra-precision machining technology, and aluminum-based optical components can be processed with simultaneous control over surface shape and position dimensions, thereby simplifying assembly and adjustment steps and reducing the development cycle of optical systems.

[0006] 4. Aluminum is much cheaper than optical glass, enabling rapid and low-cost manufacturing of optical payloads. In addition, aluminum alloys are lightweight, which can reduce the system weight and thus reduce launch costs.

[0007] 5. Aluminum has very high reflectivity across a wide spectral range, from infrared and visible light to ultraviolet light, enabling multispectral imaging.

[0008] Patent CN 120866750A discloses an optical microcrystalline aluminum material, its preparation method, and its uses. The aluminum alloy ingot is subjected to two extrusion processes to obtain extruded bars. The extrusion temperature during the first extrusion is 275–325°C, and the extrusion ratio is 2–8. The extrusion temperature during the second extrusion is 375–425°C, and the extrusion ratio is 20–30. The extruded bars are then subjected to annealing, drawing, and stabilization heat treatment sequentially to obtain the optical microcrystalline aluminum material. The stabilization heat treatment temperature is 90–240°C. The aluminum alloy is a 5-series aluminum alloy. Summary of the Invention

[0009] The technical problem to be solved by the present invention is to provide a method for preparing optical microcrystalline aluminum alloy rods, while improving hardness and reducing surface roughness of the product.

[0010] This invention provides a method for preparing optical microcrystalline aluminum alloy rods, wherein an aluminum alloy ingot is subjected to high-temperature rotary forging, high-temperature extrusion, intermediate annealing, high-temperature secondary extrusion, and stabilization treatment in sequence to obtain optical microcrystalline aluminum alloy rods. The heating temperature for high-temperature rotary forging is 300-350℃, the processing temperature for high-temperature extrusion is 250-350℃, the intermediate annealing temperature is 380-430℃, and the temperature for high-temperature secondary extrusion is 250-350℃.

[0011] Preferably, the heating temperature for high-temperature rotary forging is 310-330℃, the processing temperature for high-temperature extrusion is 280-320℃, the intermediate annealing temperature is 390-410℃, and the temperature for high-temperature secondary extrusion is 310-330℃.

[0012] Preferably, the feed rate of the high-temperature rotary forging is 1-3 mm / s, and the rotation speed is 2-5 r / s.

[0013] Preferably, the extrusion ratio of the high-temperature extrusion is 25-28.

[0014] Preferably, the intermediate annealing time is 1-3 hours, the cooling method is water quenching, and the transfer time does not exceed 10 seconds.

[0015] Preferably, the extrusion ratio of the high-temperature secondary extrusion is 4-6.

[0016] Preferably, the stabilization treatment is performed at a temperature of 140-180°C for 1-4 hours.

[0017] Preferably, the aluminum alloy ingot is a 5-series aluminum alloy ingot.

[0018] Preferably, the 5-series aluminum alloy ingot comprises the following components by mass percentage: Mg 4-5%, balance Al.

[0019] Preferably, the method for preparing the aluminum alloy ingot is as follows: the components of the aluminum alloy ingot are melted at 700-750°C, a refining agent is added for degassing, then slag is removed, and the ingot is cast to obtain the aluminum alloy ingot.

[0020] The beneficial effects of this invention are that, generally speaking, the size of the residual crystalline phase and the grain size directly affect the strength and formability of the bar stock. This invention eliminates the ingot homogenization heat treatment process and uses plastic deformation to reduce the segregation of Mg at the grain boundaries, achieving compositional homogeneity. This invention employs high-temperature rotary forging, which promotes a denser and more uniform internal grain structure by subjecting the ingot to triaxial compressive stress. By eliminating the high-temperature homogenization treatment, temperature control during high-temperature rotary forging not only improves the formability of the ingot but also controls the internal grain size. Simultaneously, it transforms the original cast dendritic segregation into dynamic recrystallization nucleation points, eliminating stress concentration problems caused by casting defects and improving the elongation of the material. Subsequently, during high-temperature extrusion, more uniform deformation in the radial direction eliminates the localized stress generated by high-temperature rotary forging and injects dislocation density, controlling the growth of recrystallized grains. Subsequent annealing treatment controls the size, morphology, and distribution of the residual crystalline phase, making the second phase particles small, uniformly distributed, and dispersed. After quenching, high-temperature secondary extrusion and stabilization treatment are carried out, which helps to densify the grain size, improve the strength and elongation of the material, and also improve the precision and surface roughness of the material.

[0021] The forging temperature of this invention is set at 300-350℃, and the high-temperature secondary extrusion temperature is set at 250-350℃, which allows for control over product precision and facilitates performance adjustment. Annealing is incorporated between the two extrusions to facilitate the control of residual crystalline phases. The secondary extrusion further helps to break down the residual crystalline phases, resulting in smaller, more dispersed, and uniformly distributed phases. The first extrusion has a higher extrusion ratio, which better eliminates localized stress generated by forging and enhances the uniformity of grains in the radial direction. The second extrusion has a lower extrusion ratio, allowing for better plasticity control, thus allowing for better control of the bar stock's precision. Detailed Implementation

[0022] Example 1 A 5-series optical microcrystalline aluminum alloy rod comprises the following components by mass percentage: Mg 4.19% and balance Al.

[0023] The preparation method of the above-mentioned 5-series optical microcrystalline aluminum alloy rods includes the following steps: 1) Prepare the raw materials by mixing pure A1 ingots and pure Mg ingots in proportion, and then melt them in a high-purity argon furnace at a melting temperature of 730℃. After all the metals have been completely melted, add the pure Mg ingots. When adding them to the melting furnace, they should be pressed in or buried in the melt. Refine the melt at a temperature of 725℃. The melt in the furnace is refined using high-purity argon. Stir, remove slag, and after the composition in front of the furnace is qualified, let it stand for more than 20 minutes before casting. Pour the aluminum liquid into a rapid cooling mold to obtain a 200×500mm 5-series aluminum alloy ingot.

[0024] 2) Heat the ingot to 320℃ and perform high-temperature rotary forging. The feed rate for high-temperature rotary forging is 2mm / s and the rotation speed is 2r / s to obtain the billet.

[0025] 3) Heat the high-temperature rotary forged billet to 300℃ and perform high-temperature extrusion on it. Set the extrusion ratio to 25 to obtain the first extruded bar.

[0026] 4) The first extruded bar is annealed in a heat treatment furnace at a temperature of 400℃ for 2 hours. After the heat treatment is completed, the bar is removed from the furnace and air-cooled.

[0027] 5) The annealed extruded bar is subjected to high-temperature secondary extrusion at a temperature of 300℃ and an extrusion ratio of 4 to obtain the second extruded bar.

[0028] 6) Stabilize the second extruded bar at a temperature of 160℃ for 2 hours, and then air-cool it after the heat treatment is completed.

[0029] Comparative Example 1 The difference from Example 1 is that in step 2), the ingot is heated to 420°C instead of 320°C. Everything else is the same as in Example 1.

[0030] Comparative Example 2 Compared to Example 1, the difference is that in step 5), the temperature of the high-temperature secondary extrusion is set to 380°C instead of 300°C. Everything else is the same as in Example 1.

[0031] Comparative Example 3 Compared to Example 1, step 1) is the same as in Example 1. The other steps are: 2) Heat the ingot to 300℃ and perform high-temperature extrusion on it. Set the extrusion ratio to 25 to obtain the first extruded bar.

[0032] 3) Then, a second high-temperature extrusion is performed, with the temperature set at 300℃ and the extrusion ratio set at 4, to obtain the second extruded bar.

[0033] 4) The second extruded bar is annealed in a heat treatment furnace at a temperature of 400℃ for 2 hours. After the heat treatment is completed, the bar is removed from the furnace and air-cooled.

[0034] 5) Heat the annealed extruded bar to 320℃ for high-temperature rotary forging. The feed rate for high-temperature rotary forging is 2mm / s and the rotation speed is 2r / s.

[0035] 6) Stabilize the extruded bars after high-temperature rotary forging at a temperature of 160℃ for 2 hours, and then air-cool them after heat preservation.

[0036] Comparative Example 4 Compared to Example 1, the difference is that step 2 is omitted. Everything else is the same as Example 1.

[0037] Comparative Example 5 Compared to Example 1, step 1) is the same as in Example 1. The other steps are: 2) Heat the ingot to 320℃ for high-temperature rotary forging. The feed rate for high-temperature rotary forging is 2mm / s and the rotation speed is 2r / s.

[0038] 3) Heat the high-temperature rotary forged billet to 300℃ and perform high-temperature extrusion on it. Set the extrusion ratio to 25 to obtain extruded bars.

[0039] 4) Then, a high-temperature secondary extrusion is performed, with the temperature set at 300℃ and the extrusion ratio set at 4, to obtain extruded bars.

[0040] 5) The extruded bar obtained in step 4 is annealed in a heat treatment furnace at a temperature of 400℃ for 2 hours. After the heat treatment is completed, the bar is removed from the furnace and air-cooled.

[0041] 6) The extruded bar obtained in step 5 is subjected to stabilization treatment at a temperature of 160℃ for 2 hours. After the stabilization is completed, the bar is removed from the furnace and air-cooled.

[0042] Comparative Example 6 The difference compared to Example 1 is as follows: The extrusion ratio for the high-temperature extrusion in step 3) is set to 4, and the extrusion ratio for the high-temperature secondary extrusion in step 5) is set to 25. Everything else is the same as in Example 1.

[0043] The performance of the aluminum alloy bars in the different embodiments and comparative examples described above is summarized in Table 1.

[0044] Table 1. Properties of different 5-series optical microcrystalline aluminum alloy rods

[0045] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of protection of this application is limited to these examples; within the framework of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of one or more embodiments of this application as described above, which are not provided in detail for the sake of brevity.

[0046] 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. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of one or more embodiments in this application should be included within the protection scope of this application.

Claims

1. A method for preparing optical microcrystalline aluminum alloy rods, characterized in that, Aluminum alloy ingots are subjected to high-temperature rotary forging, high-temperature extrusion, intermediate annealing, high-temperature secondary extrusion, and stabilization treatment in sequence to obtain optical microcrystalline aluminum alloy rods. The heating temperature for high-temperature rotary forging is 300-350℃, the processing temperature for high-temperature extrusion is 250-350℃, the intermediate annealing temperature is 380-430℃, and the temperature for high-temperature secondary extrusion is 250-350℃.

2. The preparation method according to claim 1, characterized in that, The heating temperature for high-temperature rotary forging is 310-330℃, the processing temperature for high-temperature extrusion is 280-320℃, the intermediate annealing temperature is 390-410℃, and the temperature for high-temperature secondary extrusion is 310-330℃.

3. The preparation method according to claim 1, characterized in that, The feed rate of the high-temperature rotary forging is 1-3 mm / s, and the rotation speed is 2-5 r / s.

4. The preparation method according to claim 1, characterized in that, The extrusion ratio of the high-temperature extrusion is 25-28.

5. The preparation method according to claim 1, characterized in that, The intermediate annealing time is 1-3 hours, the cooling method is water quenching, and the transfer time does not exceed 10 seconds.

6. The preparation method according to claim 1, characterized in that, The extrusion ratio of the high-temperature secondary extrusion is 4-6.

7. The preparation method according to claim 1, characterized in that, The stabilization treatment is performed at a temperature of 140-180℃ for 1-4 hours.

8. The preparation method according to claim 1, characterized in that, The aluminum alloy ingot is a 5-series aluminum alloy ingot.

9. The preparation method according to claim 8, characterized in that, The 5-series aluminum alloy ingot comprises the following components by mass percentage: Mg 4-5%, balance Al.

10. The preparation method according to claim 1, characterized in that, The method for preparing the aluminum alloy ingot is as follows: the components of the aluminum alloy ingot are melted at 700-750℃, a refining agent is added for degassing, then slag is removed, and the ingot is cast to obtain the aluminum alloy ingot.

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