Post-processing method for aluminum alloy solid-phase frictionally generated additive components

Abstract

The application discloses a composite post-processing method of an aluminum alloy solid-phase frictional additive component, which is suitable for heat-treatable strengthening aluminum alloys 2 series, 6 series and 7 series prepared by a solid-phase frictional additive method, and comprises preliminary cryogenic treatment, preliminary stress relief treatment, solid solution treatment, secondary cryogenic treatment, deep cryogenic deformation treatment, secondary stress relief treatment and aging treatment. The composite post-processing method can significantly reduce residual stress of the additive component, improve dislocation density of the component and refine grains by firstly performing cryogenic treatment before solid solution treatment and respectively performing cryogenic treatment and deep cryogenic deformation treatment before aging treatment, and is particularly suitable for short-process integrated rapid preparation of large-size complex aluminum alloy components.

Description

Technical Field

[0001] This invention belongs to the field of solid-state triboelectric additive manufacturing, and specifically relates to a composite post-processing method for aluminum alloy solid-state triboelectric additive components. Background Technology

[0002] Aluminum alloys possess advantages such as lightweight, high strength, excellent plasticity, low-temperature toughness, electrical conductivity, thermal conductivity, and corrosion resistance, and are currently widely used in aerospace, transportation, and shipbuilding. With the development of modern industry, the demand for high-performance, large, and complex aluminum alloy structural components in high-end equipment has increased significantly. However, traditional methods of smelting, casting, forging, and machining involve numerous steps, complex processes, long production cycles, low material utilization, and high manufacturing costs, making them insufficient to meet the needs of modern industrial development. Therefore, developing advanced manufacturing technologies for aluminum alloy components has become one of the urgent problems to be solved in the industrial sector.

[0003] Additive manufacturing technology enables the rapid, high-precision, integrated fabrication of complex structural components, providing a new approach for the low-cost, short-process rapid manufacturing of complex aluminum alloy components. However, the current aluminum alloy component fabrication process based on fusion welding still has significant limitations. Due to aluminum's low melting point, chemically active and easily oxidized properties, high thermal conductivity, and the easy burning loss of alloying elements, it is difficult to obtain high-performance aluminum alloy additive components that are completely dense and free of pores and cracks through fusion welding additive manufacturing.

[0004] Solid-state friction additive manufacturing (SPM) is an advanced near-net-shape manufacturing technology that utilizes friction welding to achieve metal additive manufacturing. It possesses the inherent characteristics and advantages of solid-state friction welding, as the material does not melt or solidify during the additive process. This overcomes the inherent limitations of the more mature fusion welding additive manufacturing technology, which involves localized melting and layered deposition, inevitably leading to defects such as alloy element volatilization, porosity, and cracks that cannot be completely eliminated by methods like compositional control, hot isostatic pressing, and mechanical rolling. Currently, friction additive manufacturing technology capable of using filler materials is one of the most cutting-edge technologies in the field of solid-state additive manufacturing. This type of additive process is essentially a shoulder-assisted friction welding process, offering greater flexibility and suitability for machining parts with complex geometries. It can form large-size metal components and provides a new avenue for developing high-performance lightweight alloy additive manufacturing components, making it a solid-state friction additive manufacturing method with greater development potential.

[0005] Currently, solid-state friction additive manufacturing (SPM) has been applied both domestically and internationally to the processing and manufacturing of aluminum alloy additive samples and simple components. Studies have shown that the peak temperature during SPM manufacturing can reach 70%-80% of the melting point of aluminum alloys, exceeding the dissolution temperature of the main strengthening phases. Therefore, in heat-treatable multilayer SPM additive manufacturing of aluminum alloys, almost all the main strengthening phases dissolve, resulting in severe softening of the prepared aluminum alloy additive components. Their tensile strength is only 50-60% of the original base material, making them unsuitable for engineering applications. Innovative heat treatment processes must be developed to control the microstructure and properties of the additive components. SPM additive manufacturing involves multilayer cumulative frictional extrusion thermoplastic deformation. During the additive process, the preceding deposited layer is repeatedly affected by the frictional heat and plastic deformation applied by the subsequent deposited layer, which is significantly different from the traditional single-pass friction stir welding process. Due to the high stacking fault energy of aluminum alloys, it is difficult for the multi-layer thermoplastic deformation in solid-state triboelectric additive manufacturing to produce a complete dynamic recrystallization process. The resulting fine grains contain a significant amount of stored plastic deformation energy, which decreases continuously as the reinforcing phase particles dissolve and their pinning effect on grain boundaries. If this printed additive is subjected to conventional high-temperature heat treatment, a few grains will continue to engulf the original fine grains, resulting in secondary recrystallization and the formation of abnormally large grains. The presence of these abnormally large grains significantly reduces the overall mechanical properties of aluminum alloy solid-state triboelectric additive components.

[0006] Currently, there are many research reports on how to suppress abnormal grain growth in solid-state friction stir welds during subsequent conventional heat treatment. For example, the deformation heating composite heat treatment process can limit abnormal grain growth to a certain extent, but it still cannot completely eliminate the abnormal grain growth phenomenon (Vysotskiy I, Malopheyev S, Mironov S, et al. Effect of pre-strain path on suppression of abnormal grain growth infriction-stir welded 6061aluminum alloy[J].Materials Science and Engineering:A,2019,760:206-213). Compared with welded specimens prepared by solid-state single-pass friction stir welding, aluminum alloy components prepared by solid-state friction additive manufacturing suffer from more severe abnormal grain growth in the additive region during subsequent conventional heat treatment due to the presence of multiple deposition interfaces (Beck SC, Rutherford BA, Avery DZ, et al. The effect of solutionizing and artificial aging on the microstructure and mechanical properties in solid-state additive manufacturing of precipitation hardened Al–Mg–Si alloy[J]. Materials Science and Engineering:A,2021,819:141351.). This significantly affects the overall performance of solid-state friction additive manufacturing specimens and substantially limits the engineering application of solid-state friction additive manufacturing technology. Therefore, how to control the microstructure and properties of aluminum alloy solid-state friction additive components, eliminate the softening phenomenon in the additive region, and avoid abnormal grain growth are urgent problems to be solved in the field of solid-state friction additive manufacturing.

[0007] Therefore, there is an urgent need for a composite post-processing method applicable to the microstructure and performance control of aluminum alloy solid-phase triboelectric additive components. Summary of the Invention

[0008] The purpose of this invention is to overcome the shortcomings of the prior art and propose a composite post-treatment method of heat treatment and cryogenic deformation for aluminum alloy solid-phase friction additive components. The composite post-treatment method first performs cryogenic treatment before solution treatment, and then performs cryogenic treatment and cryogenic deformation treatment before aging treatment. This method can significantly reduce the residual stress of the additive component, increase the dislocation density of the component, and refine the grains. It is particularly suitable for the short-process integrated rapid fabrication of large-size complex aluminum alloy components.

[0009] A composite post-processing method for aluminum alloy solid-phase triboelectric additive manufacturing components is applicable to heat-treatable 2-series, 6-series, and 7-series aluminum alloys prepared by solid-phase triboelectric additive manufacturing. The aluminum alloy components have a thickness of 2-2000 mm, and are particularly suitable for large-size components in the meter range (50 mm-2000 mm). The method includes:

[0010] Step 1: Preliminary cryogenic treatment: The prepared aluminum alloy components are placed in a liquid nitrogen cryogenic device for cryogenic treatment, and then restored to room temperature in an air or inert gas environment after cryogenic treatment.

[0011] Step 2: Preliminary stress relief treatment: Place the aluminum alloy component obtained in Step 1 and restored to room temperature into an inert gas protective heating device for heating and holding for a certain period of time, and then remove it from the furnace and air cool to room temperature;

[0012] Step 3: Solution treatment: The aluminum alloy component obtained in Step 2 after preliminary stress relief treatment is subjected to solution treatment, and quenching and cooling are performed immediately after the solution treatment is completed.

[0013] Step 4: Secondary cryogenic treatment: The aluminum alloy components obtained in Step 3 after solution treatment are placed in a liquid nitrogen cryogenic device for cryogenic treatment.

[0014] Step 5: Cryogenic Deformation Treatment: Immediately remove the aluminum alloy component obtained in Step 4 after cryogenic treatment and place it in a liquid nitrogen cryogenic deformation device for cryogenic deformation treatment.

[0015] Step Six: Secondary Stress Relief Treatment: Place the aluminum alloy component obtained in Step Five after cryogenic deformation into an inert gas protective heating device for heating and holding at that temperature for a certain period of time, and then remove it from the furnace and air cool it to room temperature.

[0016] Step 7: Aging treatment: The aluminum alloy components obtained in Step 6 after stress relief treatment are subjected to aging treatment, and then air-cooled to room temperature after aging treatment.

[0017] Furthermore, the inert gas protective heating device or solid solution heating device is selected from one of the following: salt bath furnace, atmosphere furnace, vacuum drying oven, induction heating device and laser heating device.

[0018] Furthermore, the preparation of the aluminum alloy component includes: selecting additive friction stir deposition technology, friction extrusion additive manufacturing technology, or friction stir additive manufacturing technology to achieve single-pass multilayer or multi-pass multilayer deposition on the substrate to obtain an aluminum alloy component with the designed shape and size; in the additive process, the shoulder rotation speed is 100-1000 rpm, and the shoulder movement speed is 50-400 mm / min.

[0019] Further, step one specifically includes: placing the aluminum alloy component obtained in step one and restored to room temperature into a liquid nitrogen cryogenic device, with the liquid nitrogen temperature controlled at -196 to -135°C, the cooling rate at 35-75°C / h, and the holding time at (effective thickness / 20mm) hours. If the effective thickness / 20mm is not an integer, it is rounded up. After the holding time is completed, the component is restored to room temperature in the air.

[0020] Furthermore, the heating device mentioned in step two is selected from one of the following: salt bath furnace, atmosphere furnace, vacuum drying oven, induction heating device and laser heating device; the heating temperature is 60-120℃, and the holding time is (effective thickness / 50mm) hours. When the effective thickness / 50mm is not an integer, it is rounded up.

[0021] Furthermore, step three specifically includes: placing the aluminum alloy component obtained in step two after preliminary stress relief treatment into a solution heating device, with a solution temperature of 505-525℃, a heating rate of 10-20℃ / min, and a holding time of (effective thickness / 30mm) hours. When the effective thickness / 30mm is not an integer, it is rounded up. After the holding time is completed, it is immediately quenched and cooled by water quenching or oil quenching.

[0022] Furthermore, step four specifically includes: placing the solution-treated aluminum alloy component obtained in step three into a liquid nitrogen cryogenic device, with the liquid nitrogen temperature controlled at -196 to -135°C and the cooling rate at 35-75°C / h. When the deposition thickness is less than 100mm, the holding time is at least (effective thickness / 5mm) hours, and if effective thickness / 5mm is not an integer, it is rounded up. When the deposition thickness is greater than 100mm, the holding time is at least (20 + (effective thickness - 100) / 25) hours, and if (effective thickness - 100) / 50 is not an integer, it is rounded up. After the holding time is completed, the component is allowed to return to room temperature in the air.

[0023] Furthermore, step five specifically includes: immediately removing the cryogenically treated aluminum alloy component obtained in step four and placing it in a liquid nitrogen cryogenic deformation device for cryogenic pre-stretching deformation, cryogenic ultrasonic impact deformation, cryogenic compression deformation, or cryogenic roll forming deformation; when selecting cryogenic pre-stretching deformation, the cryogenic stretching temperature is -196 to -135℃, and the stretching deformation amount is 1.5%-10%; when selecting cryogenic ultrasonic impact deformation, the cryogenic impact temperature is -196 to -135℃. The temperature is 5℃, the diameter of the impact head is 0.5-5mm, the moving speed of the impact head is 0.5-20mm / s, the impact amplitude is 25-90μm, the offset spacing between paths is 0.1-0.6mm, and the number of impacts is 1-5. When deep cryogenic compression deformation treatment is selected, the deep cryogenic compression deformation temperature is -196 to -135℃, and the compression deformation amount is 1.0%-10%. When deep cryogenic roll forming deformation treatment is selected, the deep cryogenic roll forming temperature is -196 to -135℃, and the total roll forming deformation amount is 1-50%.

[0024] Furthermore, step six specifically includes: placing the cryogenically deformed aluminum alloy component obtained in step five into an inert gas protective heating device for heating at a temperature of 60-120℃ and holding for a time of (effective thickness / 30mm) hours. If the effective thickness / 30mm is not an integer, it is rounded up; then it is removed from the furnace and air-cooled to room temperature.

[0025] Furthermore, step seven specifically includes: subjecting the stress-relieved aluminum alloy component obtained in step six to aging treatment, with a heating temperature of 80-180℃ and a holding time of 1-30 hours, followed by air cooling to room temperature.

[0026] The beneficial effects of the composite post-processing method for aluminum alloy solid-phase triboelectric additive components described in this invention are:

[0027] The composite post-processing method first performs deep cryogenic treatment on the printed additive component before solution treatment, which can significantly reduce the residual stress of the additive component, stabilize the component size, improve the uniformity of the component structure, and significantly reduce the driving force for grain growth. This allows the additive component to withstand higher solution temperatures to obtain a fully dissolved metastable supersaturated solid solution without abnormal grain growth.

[0028] Before aging treatment, deep cryogenic treatment and deep cryogenic deformation treatment are performed on the printed additive components to significantly improve the dislocation density and refine the grains. This can promote the rapid precipitation of a large number of strengthening phases at lower aging temperatures and shorter aging times, so that the strength and toughness of the aluminum alloy additive components reach or even exceed the performance of forged aluminum alloys, thereby significantly increasing the service life of the components.

[0029] The composite post-processing method combines solid-state triboelectric additive manufacturing, traditional heat treatment, deformation treatment and cryogenic treatment to create an economical, efficient, green, environmentally friendly, flexible, highly applicable and easy-to-industrialize composite post-processing technology. The preparation process does not involve metallurgical processes such as aluminum alloy melting and solidification, and can obtain a microstructure with completely dense internal structure and fine and uniform grains. It is particularly suitable for the short-process integrated rapid preparation of large-size complex high-performance aluminum alloy components. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the composite post-processing method for the aluminum alloy solid-phase triboelectric additive component described in this invention.

[0031] Figure 2 This is a flowchart of the composite post-processing method for the aluminum alloy solid-phase triboelectric additive component described in this invention;

[0032] Figure 3 Metallographic image of grain morphology prepared by the composite post-processing method described in Example 1;

[0033] Figure 4 Metallographic image of the grain morphology prepared for Comparative Example 2. Detailed Implementation

[0034] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. The embodiments of the present invention are provided to enable those skilled in the art to better understand the invention and do not constitute any limitation on the invention. The working process and working principle of the present invention will be further described below with reference to a preferred embodiment.

[0035] Example 1: Preparation of 6061 aluminum alloy components

[0036] like Figure 1-2 As shown, a composite post-processing method for aluminum alloy solid-phase triboelectric additive components includes the following specific steps:

[0037] Step 1: Additive Fabrication of Aluminum Alloy Components: This experiment uses solid-state triboelectric additive manufacturing technology to prepare 6061 aluminum alloy cylindrical components. The substrate and consumable bar are made of 6061-T651 aluminum alloy. The substrate thickness is 6mm, and the initial diameter of the consumable bar is 20mm. The 6061 aluminum alloy substrate is polished with sandpaper and cleaned with alcohol solution. Then, the substrate is fixed on the processing platform using a tooling fixture. The consumable bar is loaded into the non-consumable rigid shoulder feeding channel, and the shoulder is moved until the distance between the shoulder surface and the substrate surface is 2mm. The additive component deposition path is set, the rotation speed of the shoulder and consumable bar is 300rpm, and the moving speed is 300mm / min. The program is started, and the deposition of a component with a total thickness of 60mm is completed according to the preset additive path, resulting in a 6061 aluminum alloy cylindrical component.

[0038] Step 2: Cryogenic treatment of aluminum alloy components: After the 6061 aluminum alloy cylindrical component prepared in Step 1 is cooled to room temperature, it is placed in a liquid nitrogen cryogenic treatment chamber. The cooling rate is set to 50℃ / h. After the temperature of the cryogenic treatment chamber drops to -190℃, it is kept at that temperature for 3 hours and then taken out and allowed to recover to room temperature in the air.

[0039] Step 3: Stress relief treatment of aluminum alloy components: Place the 6061 aluminum alloy cylindrical component, which has been restored to room temperature, into a heat treatment furnace, heat it to 100°C with the furnace, hold it at that temperature for 2 hours, and then air cool it to room temperature.

[0040] Step 4: Solution treatment of aluminum alloy components: After stress relief treatment, the components are placed in a heat treatment furnace and heated to 525°C. The heating rate is set to 20°C / min. After holding at this temperature for 2 hours, immersion water quenching is immediately carried out. The quenching transfer time is 10s. The water temperature after quenching is 35°C. The components are then left in the water for 5 minutes after quenching.

[0041] Step 5: Cryogenic treatment of aluminum alloy components: Place the solution-treated components into a liquid nitrogen cryogenic treatment chamber, set the cooling rate to 50℃ / h, and remove them after the temperature of the cryogenic treatment chamber drops to -190℃ and is kept at that temperature for 12 hours.

[0042] Step Six: Cryogenic Deformation Treatment of Aluminum Alloy Components: After cryogenic treatment, the components are immediately placed in a special stretching device for pre-stretching treatment. At the same time, the nitrogen cooling spray gun in the stretching device is turned on to continuously cool the entire component at a low temperature. When the stretching deformation reaches 6%, the components are taken out and allowed to recover to room temperature in the air.

[0043] Step 7: Stress relief treatment of aluminum alloy components: Place the components that have been restored to room temperature into a heat treatment furnace, heat them to 100°C, hold them at that temperature for 2 hours, and then air cool them to room temperature.

[0044] Step 8: Aging treatment of aluminum alloy components: After stress relief treatment, the components are placed in a heat treatment furnace and heated to 120°C for aging treatment. After holding at this temperature for 4 hours, they are air-cooled to room temperature.

[0045] Example 2:

[0046] The steps in this embodiment are similar to those in Embodiment 1, and the same content will not be repeated.

[0047] The only difference between this embodiment and Embodiment 1 is that in step six, the outer surface of the 6061 aluminum alloy cylindrical component is treated with cryogenic ultrasonic impact. The cryogenic impact temperature is -190℃, the impact amplitude is 60μm, the impact head moving speed is 5mm / s, the impact head diameter is 2mm, the offset spacing between paths is 0.25mm, and the number of impacts is 5. All other steps are exactly the same as in Embodiment 1.

[0048] Example 3: Preparation of 2219 aluminum alloy cylindrical components

[0049] The steps in this embodiment are similar to those in Embodiment 1, and the same content will not be repeated.

[0050] The only difference between this embodiment and Embodiment 1 is that:

[0051] Step 1: Additive fabrication of aluminum alloy components: The rotation speed of the shoulder and the consumable bar is 400 rpm, the moving speed is 150 mm / min, and the total thickness of the additive component is 2000 mm.

[0052] Step 2: Cryogenic treatment of aluminum alloy components: The components are cryogenically treated at -165℃ and removed after 100 hours of heat treatment;

[0053] Step 3: Stress relief treatment of aluminum alloy components: The 2219 aluminum alloy cylindrical components, which have been restored to room temperature, are heated to 80°C in the furnace, held at that temperature for 40 hours, and then air-cooled to room temperature.

[0054] Step 4: Solution treatment of aluminum alloy components: After stress relief treatment, the components are placed in a heat treatment furnace and heated to 520°C with the furnace. The heating rate is set to 15°C / min. After holding at this temperature for 70 hours, immersion water quenching is immediately carried out.

[0055] Step 5: Cryogenic treatment of aluminum alloy components: Place the solution-treated components into a liquid nitrogen cryogenic treatment chamber, set the cooling rate to 45℃ / h, and remove them after the temperature of the cryogenic treatment chamber drops to -165℃ and is kept at that temperature for 100 hours.

[0056] Step Six: Cryogenic Deformation Treatment of Aluminum Alloy Components: Immediately after cryogenic treatment, the components are subjected to cryogenic ultrasonic impact deformation treatment. The cryogenic impact temperature is -180℃, the impact head diameter is 1.5mm, the impact head moving speed is 2mm / s, the impact amplitude is 30μm, the offset spacing between paths is 0.2mm, the number of impacts is 5, and the components are allowed to recover to room temperature in air after the impact is completed.

[0057] Step 7: Stress relief treatment of aluminum alloy components: Place the components that have been restored to room temperature into a heat treatment furnace, heat them to 80°C, hold them at that temperature for 40 hours, and then air cool them to room temperature.

[0058] Step 8: Aging treatment of aluminum alloy components: After stress relief treatment, the components are placed in a heat treatment furnace and heated to 160°C for aging treatment. After holding at that temperature for 8 hours, they are air-cooled to room temperature.

[0059] Example 5: Preparation of 7075 aluminum alloy reinforcing rib components

[0060] The steps in this embodiment are similar to those in Embodiment 1, and the same content will not be repeated.

[0061] The only difference between this embodiment and Embodiment 1 is that:

[0062] Step 1: Additive fabrication of aluminum alloy components: The rotation speed of the shoulder and consumable bar is 350 rpm, the moving speed is 250 mm / min, and the total thickness of the additive component is 2 mm.

[0063] Step 2: Cryogenic treatment of aluminum alloy components: The components are cryogenically treated at -175℃ and removed after 1 hour of heat treatment;

[0064] Step 3: Stress relief treatment of aluminum alloy components: The 7075 aluminum alloy reinforcing rib components, which have been restored to room temperature, are heated to 90°C in the furnace, held at that temperature for 1 hour, and then air-cooled to room temperature.

[0065] Step 4: Solution treatment of aluminum alloy components: After stress relief treatment, the components are placed in a heat treatment furnace and heated to 470°C with the furnace. The heating rate is set to 25°C / min. After holding at this temperature for 1 hour, immersion water quenching is immediately carried out.

[0066] Step 5: Cryogenic treatment of aluminum alloy components: Place the solution-treated components into a liquid nitrogen cryogenic treatment chamber, set the cooling rate to 40℃ / h, and remove them after the temperature of the cryogenic treatment chamber drops to -175℃ and is kept at that temperature for 6 hours.

[0067] Step Six: Cryogenic Deformation Treatment of Aluminum Alloy Components: After cryogenic treatment, the components are immediately placed in a special compression device for pre-compression treatment. At the same time, the nitrogen cooling spray gun in the compression device is turned on to continuously cool the entire component at a low temperature. When the compression deformation reaches 8%, the components are taken out and allowed to recover to room temperature in the air.

[0068] Step 7: Stress relief treatment of aluminum alloy components: Place the components that have been restored to room temperature into a heat treatment furnace, heat the furnace to 90°C, hold for 1 hour, and then air cool to room temperature;

[0069] Step 8: Aging treatment of aluminum alloy components: After stress relief treatment, the components are placed in a heat treatment furnace and heated to 150°C for aging treatment. After holding at that temperature for 8 hours, they are air-cooled to room temperature.

[0070] Comparative Example 1:

[0071] This comparative example only involves solid-state triboelectric additive manufacturing, and the additive manufacturing process parameters are exactly the same as those in Example 1.

[0072] Comparative Example 2:

[0073] The difference between this comparative example and Example 1 is that the deep cryogenic treatment in step (2) is not performed after solid-state friction extrusion additive manufacturing; the other steps are exactly the same as in Example 1.

[0074] Comparative Example 3:

[0075] The difference between this comparative example and Example 1 is that the aging temperature in step (8) is 150°C, while the other aging parameters and steps are exactly the same as in Example 1.

[0076] Comparative Example 4:

[0077] The difference between this comparative example and Example 1 is that the aging and heat preservation time in step (8) is 8 hours, while the other aging parameters and steps are exactly the same as in Example 1.

[0078] The tensile properties and microhardness test data of the 6061 aluminum alloy cylindrical components prepared according to the weaving and performance treatment methods of Examples 1-2 and Comparative Examples 1-4 are shown in the table below.

[0079] Table 1. Tensile properties and microhardness test data of the examples and comparative examples.

[0080] Case Number Tensile strength / MPa Yield strength / MPa Elongation after fracture / % Microhardness / HV Example 1 345 309 15.3 121 Example 2 348 311 14.8 123 Comparative Example 1 165 110 25.0 60 Comparative Example 2 340 305 12.6 119 Comparative Example 3 305 287 13.5 108 Comparative Example 4 311 293 13.2 110

[0081] As can be seen from the experimental data in Table 1, by implementing the microstructure and performance control method of the aluminum alloy solid-phase friction additive manufacturing component described in this invention, the strength and hardness of the aluminum alloy component are significantly improved compared to the printed component (Comparative Example 1), and the strength and elongation after fracture are comparable to those of the forged aluminum alloy. Figure 3 The grain morphology observation results after Example 1 show that the microstructure and property control method of the present invention can effectively suppress abnormal growth of additive microstructure while obtaining excellent mechanical properties. Although the aluminum alloy additive component in Comparative Example 2 also obtained better mechanical properties, from... Figure 4 The grain morphology observation results after Comparative Example 2 show that the additive structure underwent significant abnormal growth. In Comparative Examples 3 and 4, excessively high aging temperatures or excessively long aging times easily led to over-aging of the additive structure, resulting in mechanical properties inferior to those of the embodiments of this invention.

[0082] Although the above description, in conjunction with the accompanying drawings, details the post-processing flow of the composite solid-phase triboelectric additive components of heat-treatable aluminum alloys of series 2, 6, and 7 to which this invention applies, this invention is not limited to the aforementioned heat-treatable aluminum alloy systems. It is also applicable to non-heat-treatable strengthened aluminum alloys of series 5, with the difference being that steps four and eight are not required.

[0083] Although the present invention has been described above in conjunction with the accompanying drawings, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many modifications under the guidance of the present invention without departing from the spirit of the present invention, and these modifications are all within the protection scope of the present invention.

Claims

1. A composite post-processing method for aluminum alloy solid-phase triboelectric additive manufacturing components, wherein the post-processing method is applicable to heat-treatable aluminum alloys of the 2, 5, 6, and 7 series prepared by solid-phase triboelectric additive manufacturing, wherein the aluminum alloy component has a thickness of 2-2000 mm, and is particularly suitable for large-size components in the meter range of 50 mm-2000 mm; comprising: Step 1: Preliminary cryogenic treatment: The prepared aluminum alloy components are placed in a liquid nitrogen cryogenic device for cryogenic treatment, and then restored to room temperature in an air or inert gas environment after cryogenic treatment. Step 2: Preliminary stress relief treatment: Place the aluminum alloy component obtained in Step 1 and restored to room temperature into an inert gas protective heating device for heating and holding for a certain period of time, and then remove it from the furnace and air cool to room temperature; Step 3: Solution treatment: The aluminum alloy component obtained in Step 2 after preliminary stress relief treatment is subjected to solution treatment, and quenching and cooling are performed immediately after the solution treatment is completed. Step 4: Secondary cryogenic treatment: The aluminum alloy components obtained in Step 3 after solution treatment are placed in a liquid nitrogen cryogenic device for cryogenic treatment. Step 5: Cryogenic Deformation Treatment: Immediately remove the aluminum alloy component obtained in Step 4 after cryogenic treatment and place it in a liquid nitrogen cryogenic deformation device for cryogenic deformation treatment. Step Six: Secondary Stress Relief Treatment: Place the aluminum alloy component obtained in Step Five after cryogenic deformation into an inert gas protective heating device for heating and holding at that temperature for a certain period of time, and then remove it from the furnace and air cool it to room temperature. Step 7: Aging treatment: The aluminum alloy components obtained in Step 6 after stress relief treatment are subjected to aging treatment, and then air-cooled to room temperature after aging treatment.

2. The composite post-processing method for aluminum alloy solid-phase triboelectric additive components according to claim 1, characterized in that, The inert gas protective heating device or solid solution heating device is selected from one of the following: salt bath furnace, atmosphere furnace, vacuum drying oven, induction heating device and laser heating device.

3. The composite post-processing method for aluminum alloy solid-phase triboelectric additive components according to claim 1, characterized in that, The preparation of the aluminum alloy component includes: selecting additive friction stir deposition technology, friction extrusion additive manufacturing technology, or friction stir additive manufacturing technology to achieve single-pass multilayer or multi-pass multilayer deposition on the substrate to obtain an aluminum alloy component with the designed shape and size; the shoulder rotation speed in the additive process is 100-1000 rpm, and the shoulder moving speed is 50-400 mm / min.

4. The composite post-processing method for aluminum alloy solid-phase triboelectric additive components according to claim 1, characterized in that, Step one specifically includes: placing the aluminum alloy component obtained in Step one and restored to room temperature into a liquid nitrogen cryogenic device, with the liquid nitrogen temperature controlled at -196 to -135℃, the cooling rate at 35-75℃ / h, and the holding time at (effective thickness / 20mm) hours. If the effective thickness / 20mm is not an integer, it is rounded up. After the holding time is completed, the component is restored to room temperature in the air.

5. The composite post-processing method for aluminum alloy solid-phase triboelectric additive components according to claim 1, characterized in that, The heating device mentioned in step two is selected from one of the following: salt bath furnace, atmosphere furnace, vacuum drying oven, induction heating device and laser heating device; the heating temperature is 60-120℃, and the holding time is (effective thickness / 50mm) hours. When the effective thickness / 50mm is not an integer, it is rounded up.

6. The composite post-processing method for aluminum alloy solid-phase triboelectric additive components according to claim 1, characterized in that, Step 3 specifically includes: placing the aluminum alloy component obtained in Step 2 after preliminary stress relief treatment into a solution heating device, with a solution temperature of 505-525℃, a heating rate of 10-20℃ / min, and a holding time of (effective thickness / 30mm) hours. When the effective thickness / 30mm is not an integer, it is rounded up. After the holding time is completed, it is immediately quenched and cooled by water quenching or oil quenching.

7. The composite post-processing method for aluminum alloy solid-phase triboelectric additive components according to claim 1, characterized in that, Step four specifically includes: placing the solution-treated aluminum alloy component obtained in step three into a liquid nitrogen cryogenic device, with the liquid nitrogen temperature controlled between -196 and -135°C and the cooling rate at 35-75°C / h. When the deposition thickness is less than 100mm, the holding time should be at least (effective thickness / 5mm) hours, and if effective thickness / 5mm is not an integer, it should be rounded up. When the deposition thickness is greater than 100mm, the holding time should be at least (20 + (effective thickness - 100) / 25) hours, and if (effective thickness - 100) / 50 is not an integer, it should be rounded up. After the holding time is completed, the component should be allowed to return to room temperature in the air.

8. The composite post-processing method for aluminum alloy solid-phase triboelectric additive components according to claim 1, characterized in that, Step five specifically includes: immediately removing the cryogenically treated aluminum alloy component obtained in step four and placing it in a liquid nitrogen cryogenic deformation device for cryogenic pre-stretching deformation, cryogenic ultrasonic impact deformation, cryogenic compression deformation, or cryogenic roll forming deformation. When cryogenic pre-stretching deformation is selected, the cryogenic stretching temperature is -196 to -135℃, and the stretching deformation amount is 1.5% to 10%. When cryogenic ultrasonic impact deformation is selected, the cryogenic impact temperature is -196 to -135℃. The impact head diameter is 0.5-5mm, the impact head moving speed is 0.5-20mm / s, the impact amplitude is 25-90μm, the offset spacing between paths is 0.1-0.6mm, and the number of impacts is 1-5. When cryogenic compression deformation treatment is selected, the cryogenic compression deformation temperature is -196 to -135℃, and the compression deformation amount is 1.0%-10%. When cryogenic roll forming deformation treatment is selected, the cryogenic roll forming temperature is -196 to -135℃, and the total roll forming deformation amount is 1-50%.

9. The composite post-processing method for aluminum alloy solid-phase triboelectric additive components according to claim 1, characterized in that, Step six specifically includes: placing the cryogenically deformed aluminum alloy component obtained in step five into an inert gas protective heating device for heating at a temperature of 60-120℃ and holding for a time of (effective thickness / 30mm) hours. If the effective thickness / 30mm is not an integer, it is rounded up. Then, the component is removed from the furnace and air-cooled to room temperature.

10. The composite post-processing method for aluminum alloy solid-phase triboelectric additive components according to claim 1, characterized in that, Step seven specifically includes: aging the stress-relieved aluminum alloy components obtained in step six, heating at 80-180℃, holding for 1-30 hours, and then air-cooling to room temperature.

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