Astronautical aluminum-lithium alloy brace 3D printing light weight method

Abstract

The application discloses a kind of aerospace aluminum lithium alloy brace 3D printing light weight method, it is related to aluminum lithium alloy technical field.The method includes preparation CeO2-La2O3@TiB2 core-shell structure nano modifier;It is evenly coated on the surface of aluminum lithium alloy base powder by acoustic resonance intermittent pulse mode;After static high vacuum low-temperature degassing treatment, based on finite element topology optimization design, different regions of brace are designed as full dense entity, BCC lattice and Gyroid minimum surface lattice structure respectively, and are exported as 3MF multi-entity file;Blow-suction type ground air knife assisted partition laser selective melting forming is used, pure contour scanning is used to lattice area;Finally, step strengthening hot isostatic pressing, high-pressure gas quenching solid solution aging and alternating pulsating pressure chemical milling and passivation treatment are carried out.The aluminum lithium alloy brace prepared by the application has good mechanical strength and light weight effect.

Description

Technical Field

[0001] This invention relates to the field of aluminum-lithium alloy technology, specifically to a method for 3D printing lightweight aluminum-lithium alloy supports for aerospace applications. Background Technology

[0002] Aluminum-lithium alloys, as a new generation of lightweight structural materials for aerospace applications, benefit from the low density of lithium. Adding 1 wt% lithium can reduce the alloy's density by approximately 3% and increase its elastic modulus by approximately 5%. Simultaneously, they possess high strength, excellent fatigue resistance, and corrosion resistance, making them a preferred material for load-bearing supports in core components such as aerospace engines, satellites, and spacecraft cabins. Aerospace aluminum-lithium alloy supports not only require high mechanical strength to meet load-bearing demands under extreme conditions but also need to achieve extreme lightweighting to reduce the overall weight of aerospace equipment. Furthermore, due to the increasing integration of equipment, support structures are becoming more complex, placing higher demands on the precision of the forming process and the ability to achieve integrated molding.

[0003] Currently, the main manufacturing processes for aluminum-lithium alloys include traditional casting, powder metallurgy, and selective laser melting (SLM) 3D printing. While casting is widely used, it suffers from problems such as severe lithium volatilization and oxidation, significant casting segregation, and coarse grains, which limit the amount of lithium added. It is also prone to hot and cold cracking defects, resulting in low yields of large-size ingots and large amounts of subsequent machining, making it impossible to achieve integrated molding of complex topological structures. Although powder metallurgy can improve alloy properties through dispersion strengthening and partially solve the problem of limited lithium content, it still relies on subsequent plastic processing and machining, resulting in low material utilization and insufficient ability to form complex structures, making it difficult to meet the customized and complex structural requirements of aerospace supports.

[0004] Laser selective melting 3D printing technology has become the core development direction for the preparation of complex aluminum-lithium alloy components for aerospace due to its advantages of integrated molding of complex structures, high material utilization and high molding precision. However, the existing SLM3D printing technology for aluminum-lithium alloy supports is difficult to balance mechanical strength and lightweight effect. Summary of the Invention

[0005] The purpose of this invention is to provide a lightweight 3D printing method for aluminum-lithium alloy supports for aerospace applications, thereby addressing the technical problems mentioned in the background section. The aluminum-lithium alloy supports prepared by this invention possess both excellent mechanical strength and lightweight properties.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A method for lightweighting aluminum-lithium alloy supports for aerospace applications using 3D printing includes the following steps: (1) The nano-TiB2 powder was ultrasonically dispersed in anhydrous ethanol, cerium isopropoxide and lanthanum isopropoxide were added, acetylacetone was added as a chelating agent, and the mixture was stirred under an inert atmosphere. Then, an aqueous ethanol solution was added dropwise and stirred continuously to form a precursor sol. After centrifugation, washing and drying, the mixture was first heated in an air atmosphere and then calcined in an inert atmosphere to obtain CeO2-La2O3@TiB2 core-shell structure nano-modifier. (2) The aluminum-lithium alloy base powder and CeO2-La2O3@TiB2 core-shell structure nano-modifier were loaded into a vacuum mixing tank, vacuumed and filled with inert gas, and then mixed in an acoustic resonance mixer using an intermittent pulse mode to make the nano-modifier uniformly coated on the surface of the base powder to obtain composite powder. (3) Spread the composite powder evenly in the tray and place it in a static high vacuum drying oven. Perform static degassing at a temperature lower than the alloy solution temperature to obtain the degassed composite powder. (4) The support was optimized by finite element analysis, and different stress bearing areas were divided. They were designed as fully dense solid structures, BCC lattice structures and Gyroid minimal surface lattice structures, and each area was exported as an independent entity as a 3MF multi-body assembly file. (5) The degassed composite powder is loaded into the powder cylinder of the selective laser melting equipment. Under the protection of an inert atmosphere, the substrate is preheated. The airflow is controlled by a blow-suction dual-channel ground-mounted air knife. The solid filling parameters are used for laser scanning of the fully dense solid and BCC lattice areas, and the pure contour scanning parameters are used for laser scanning of the Gyroid lattice areas. Layered molding is performed to obtain the support blank. (6) Place the support blank in a hot isostatic pressing furnace, and under an inert atmosphere, first heat it to a temperature below the eutectic temperature and hold it, then heat it to the solution temperature and pressurize it, and then cool it slowly. (7) Place the support obtained after step (6) in a vacuum heat treatment furnace, evacuate and heat it stepwise, then fill it with high-pressure helium and cool it quickly, and then perform aging treatment. (8) Place the support obtained after step (7) in a flow pool, rinse it with alkaline solution under alternating pulsating pressure, then wash it with pure water, then immerse it in deoxygenation brightening solution for treatment, after washing it, immerse it in trivalent chromium conversion solution for passivation treatment, and finally dry it.

[0007] In the technical solution of this invention, (1) the principle of achieving high mechanical strength of aluminum-lithium alloy supports is as follows: First, a CeO2-La2O3@TiB2 core-shell structure nanomodifier with no carbon pollution, uniform shell layer and retaining TiB2 nucleation activity is prepared by chelating sol-gel and decarburizing calcination process. This modifier can effectively refine alloy grains as a heterogeneous nucleation point, and rare earth oxides can also purify the melt and reduce the crack sensitivity of the alloy. The acoustic resonance intermittent coating process is used to firmly anchor the nanomodifier to the surface of the base powder in a pure environment with zero additives, which ensures the modification. The agent is dispersed uniformly and the powder maintains high sphericity, laying a good foundation for subsequent molding. Static high-vacuum low-temperature degassing treatment removes the source of hydrogen pores and avoids molding defects. Finally, the internal micro-metallurgical pores are healed by step-strengthened hot isostatic pressing treatment to prevent TIP expansion and cracking. Combined with high-pressure gas quenching solution-aging treatment to prevent air loss, the precipitation strengthening, fine grain strengthening and TiB2 dispersion strengthening of the alloy are achieved in synergy. At the same time, the collapse of the lattice structure and dimensional deformation are avoided, which ultimately greatly improves the tensile strength, density and mechanical property stability of the aluminum-lithium alloy support. (2) The principle of achieving lightweight aluminum-lithium alloy supports is as follows: First, based on finite element analysis, a digital design of the macro-micro structural gradient topology is carried out using a multi-solid format. According to different stress gradient regions of the support, a fully dense solid, BCC lattice, and minimal curved surface Gyroid lattice structure are designed respectively. The independent boundary properties of each region are preserved through the 3MF multi-solid format, so as to achieve precise matching between the structure and the actual load-bearing stress. The low relative density of the lattice structure is used to significantly reduce the overall mass of the support, thus achieving structural lightweighting. Then, a partitioned laser forming process with a blow-suction type ground-mounted air knife to suppress plasma plumes is adopted. Through precise partitioned laser parameter control, the contradiction between strong wind blowing powder and weak wind blocking light is solved, while achieving high-definition sharp forming of thin-walled microstructures, ensuring the forming accuracy and structural integrity of the lightweight lattice structure. Combined with slow-release chemical milling with alternating pulsating pressure and light-emitting anti-corrosion treatment, the complex microchannel powder and slag are safely removed without damaging the lightweight lattice structure. Finally, without sacrificing the load-bearing performance of the support, a significant improvement in lightweighting effect is achieved.

[0008] Preferably, in step (1), the molar ratio of cerium isopropoxide to lanthanum isopropoxide is 1:1.

[0009] Preferably, in step (2), the aluminum-lithium alloy base powder comprises the following components: Li 1.2-1.8wt%, Cu 2.0-3.0wt%, Mg 0.5-1.0wt%, Zr 0.08-0.15wt%, balance being Al and unavoidable trace impurities.

[0010] Preferably, in step (2), the aluminum-lithium alloy base powder has a particle size distribution of 15-53 μm and a sphericity of ≥98%.

[0011] Preferably, in step (2), the mass ratio of aluminum-lithium alloy base powder to CeO2-La2O3@TiB2 core-shell structure nanomodifier is 500:(5-10).

[0012] Preferably, in step (2), zinc and bismuth are also added to the mixing tank.

[0013] Preferably, in step (2), the amount of zinc added is 0.5 to 0.8 wt% of the aluminum-lithium alloy base powder; and the amount of bismuth added is 0.05 to 0.1 wt% of the aluminum-lithium alloy base powder.

[0014] In experiments, this invention revealed that while the CeO2-La2O3@TiB2 nanoparticles introduced into the aluminum-lithium alloy base powder significantly improved the mechanical strength of the matrix, they also generated a strong particle pinning effect during selective laser melting, leading to a sharp increase in the kinetic viscosity of the liquid aluminum alloy pool. This resulted in the extremely viscous melt failing to flow smoothly and spread due to insufficient thermal energy when performing lightweight structural modification (i.e., using low-power fine laser scanning to form an extremely small curved lattice with a wall thickness of only 0.5 mm). This caused a severe spheroidization effect, resulting in the discontinuous formation of lightweight microfilaments, surface slag buildup, or even complete collapse and scrapping, thus seriously affecting the formation of lightweight aluminum-lithium alloy structures. To address this technical problem, this invention introduces a specific amount of zinc (0.5–0.8 wt%) and bismuth (0.05–0.1 wt%) into the aluminum-lithium alloy base powder, constructing a synergistic regulation system for the rheological properties of the molten pool with an internally dilute and externally expanded structure. High-solid-solid-content Zn acts as a high-temperature lubricant at the atomic scale, significantly reducing the liquidus temperature and molten pool viscosity of the alloy, offsetting the thickening effect of nanoparticles to restore rheological dynamics. Meanwhile, Bi, with its large atomic radius and extreme difficulty in solid dissolution, instantly agglomerates at the gas-liquid interface of the molten pool under laser irradiation, acting as a powerful metallic "surfactant" and significantly reducing the liquid surface tension of the aluminum melt. The synergistic effect of these two elements, under extremely low heat input conditions, reactivates and greatly enhances Marangoni convection within the molten pool, forcing the viscous melt containing numerous nanoparticles to instantly spread and wet, thus completely solving the spheroidization problem and ensuring high-definition, continuous, and sharp forming of complex, extremely fine structures as small as 0.5 mm. This achieves lightweight aluminum-lithium alloy structures while maintaining high strength.

[0015] Preferably, in step (5), the substrate preheating temperature is 125-130°C.

[0016] Preferably, in step (7), the aging treatment temperature is 150-160℃ and the aging treatment time is 20-25h.

[0017] Preferably, in step (8), the deoxygenated light-emitting liquid is composed of HNO3 and CrO3.

[0018] Compared with the prior art, the beneficial effects of the present invention are: 1. By preparing carbon-free CeO2-La2O3@TiB2 core-shell structure nanomodifiers, and combining acoustic resonance coating and hot isostatic pressing processes, the synergistic effect of fine grain strengthening, dispersion strengthening and precipitation strengthening was achieved, which significantly improved the tensile strength, density and mechanical stability of aluminum-lithium alloy supports.

[0019] 2. Based on finite element analysis, a digital design of macro- and micro-gradient topology is carried out. Fully dense solids and lattice structures are matched for different stress regions. Combined with partitioned laser forming and slow-release chemical milling processes, thin-walled microstructures are precisely formed while ensuring load-bearing performance, which significantly reduces the overall weight of the support.

[0020] 3. To address the problem of increased melt viscosity and difficulty in forming fine lattice structures caused by nano-modifiers, a melt pool rheology control system was constructed by quantitatively introducing Zn and Bi elements. Under low heat input conditions, Marangoni convection was activated, which completely solved the spheroidization effect and ensured the high-quality forming of complex microfilament structures at the 0.5mm level. Attached Figure Description

[0021] Figure 1 This is a low-magnification SEM image of the surface of the aluminum-lithium alloy bracket prepared in Example 1 of the present invention.

[0022] Figure 2 This is a high-magnification SEM image of the surface of the aluminum-lithium alloy bracket prepared in Example 1 of the present invention.

[0023] Figure 3 The image shows the XRD pattern of the aluminum-lithium alloy support prepared in Example 1 of this invention.

[0024] Figure 4 This is a SEM image of the CeO2-La2O3@TiB2 core-shell structured nanomodifier prepared in this invention.

[0025] Figure 5 The XRD pattern of the CeO2-La2O3@TiB2 core-shell structured nanomodifier prepared in this invention. Detailed Implementation

[0026] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention. Example 1

[0027] A method for lightweighting aluminum-lithium alloy supports for aerospace applications using 3D printing includes the following steps: Step 1: 45g of nano-TiB2 powder with a particle size of 30-80nm was ultrasonically dispersed in 1L of anhydrous ethanol. Then, 0.15mol of cerium isopropoxide and 0.15mol of lanthanum isopropoxide were added, followed by slow dropwise addition of 0.3mol of acetylacetone as a chelating agent. The mixture was placed in a sealed three-necked flask purged with high-purity argon and magnetically stirred at 60℃ for 2h. 5mL of deionized water was diluted in 50mL of anhydrous ethanol and slowly added to the system at a rate of 1 drop / second, with continuous stirring for 4h to form a precursor sol. The product was centrifuged and washed three times with anhydrous ethanol, then vacuum dried. It was then placed in a tube furnace and heated at 250℃ for 1h in air, followed by rapid switching to high-purity argon protection and heating to 400℃ for calcination for 2h. After cooling, CeO2-La2O3@TiB2 core-shell structure nano-modifier was obtained.

[0028] Step 2: Select 2500g of aluminum-lithium alloy base powder with a particle size distribution of 15-53μm and a sphericity ≥98%. The mass fraction of its components is: Li 1.8%, Cu 3.0%, Mg 1.0%, Zr 0.15%, with the remainder being Al and unavoidable trace impurities. 2500g of this aluminum-lithium alloy base powder and 45g of CeO2-La2O3@TiB2 core-shell structure nano-modifier obtained in step (1) are loaded into a vacuum mixing tank. At the same time, 18g of zinc and 2.2g of bismuth are added to the mixing tank. The mixing tank is evacuated and filled with high-purity argon gas, and then fixed on an acoustic resonance mixer. The resonance frequency is set to 60Hz and the acceleration to 60G. An intermittent pulse mode is used, running for 3 minutes and then stopping for 2 minutes to cool down. The mixture is run for a total of 15 minutes to ensure that the nano-modifier is uniformly coated on the surface of the base powder, thus obtaining a composite powder.

[0029] Step 3: Spread the composite powder obtained in step (2) evenly in a stainless steel tray, controlling the powder layer thickness to ≤2cm, and place the whole thing in a static high vacuum drying oven. Turn on the vacuum pump group to evacuate to the ultimate vacuum degree ≤1×10 -3 The heating temperature was set to 80℃, and static degassing was carried out continuously at this temperature and vacuum for 4 hours. After the process was completed, the powder was allowed to cool naturally to room temperature in the furnace, then removed and sealed to obtain the degassed composite powder.

[0030] Step 4: Import the 3D model of the aerospace support to be printed into finite element analysis software for topology optimization, dividing it into different stress-bearing regions according to the stress conditions. The high-load-bearing region is designed as a fully dense solid structure; the secondary load-bearing region is designed as a BCC lattice structure with a rod diameter of 1.0 mm and a relative density of 60%; the non-load-bearing region is designed as a Gyroid minimal surface lattice structure with a wall thickness of 0.5 mm and a relative density of 20%. After completing Boolean operations, the above three regions are treated as independent entities and exported as a single 3MF multi-body assembly file.

[0031] Step 5: Load the degassed composite powder into the powder cylinder of the selective laser melting equipment. After evacuating the forming cavity, fill it with high-purity argon gas, controlling the oxygen content to ≤10ppm. Turn on the substrate heating module and set the substrate preheating temperature to 128℃. Place a blow-suction dual-channel ground-level air knife above the forming surface and control the airflow velocity between 1.5 and 2.0m / s. Import the 3MF file generated in step (4), and perform laser scanning on the fully dense solid and BCC lattice areas using solid filling parameters (laser power 280W, scanning speed 1000mm / s, scanning spacing 90μm). Perform laser scanning on the Gyroid minimal curved surface lattice areas using pure contour scanning parameters (laser power 120W, scanning speed 800mm / s). Set the powder layer thickness to 30μm, form in layers, and clean the floating powder after printing to obtain the support blank.

[0032] Step 6: Place the support blank with the substrate in a hot isostatic pressing furnace, and introduce high-purity argon gas as the pressure transfer medium. Heat to 480℃ at a heating rate of 5℃ / min and hold for 2 hours; then continue heating to 500℃, simultaneously pressurizing to 100MPa, and hold at this temperature and pressure for 3 hours. After the pressure holding is completed, control the cooling rate to ≤5℃ / min and slowly cool it to room temperature in the furnace before removing it from the furnace.

[0033] Step 7: Place the support obtained in step (6) into a vacuum heat treatment furnace equipped with high-pressure gas quenching function. After evacuation, first maintain the temperature at 480℃ for 1 hour, then gradually increase the temperature to 500℃ and maintain it for another hour. After the heat treatment is completed, leave the support in place, instantly fill the furnace with high-purity helium gas at a pressure of 1.0MPa, and turn on a powerful fan for rapid cooling. After the support cools to room temperature, transfer it to an aging furnace and age it at 155℃ for 24 hours. Then remove it and air-cool it to room temperature.

[0034] Step 8: Prepare a NaOH solution at 40℃ and 40g / L as the alkali solution. Seal the support obtained in step (7) in a flow cell. Use a programmable diaphragm pump to apply an alternating pulsating pressure flow of 0.1MPa and 5Hz to continuously rinse with the alkali solution for 3 minutes, and then wash with pure water. Quickly immerse the support in a deoxygenating brightening solution composed of 30vol% HNO3 and 100g / L CrO3 at room temperature for 3 minutes. After washing with pure water, immerse the support in a trivalent chromium conversion solution at room temperature for 10 minutes for passivation treatment. Finally, remove it and dry it in a 60℃ oven to obtain the final product. Example 2

[0035] A method for lightweighting aluminum-lithium alloy supports for aerospace applications using 3D printing includes the following steps: Step 1: 45g of nano-TiB2 powder with a particle size of 30-80nm was ultrasonically dispersed in 1L of anhydrous ethanol. Then, 0.15mol of cerium isopropoxide and 0.15mol of lanthanum isopropoxide were added, followed by slow dropwise addition of 0.3mol of acetylacetone as a chelating agent. The mixture was placed in a sealed three-necked flask purged with high-purity argon and magnetically stirred at 60℃ for 2h. 5mL of deionized water was diluted in 50mL of anhydrous ethanol and slowly added to the system at a rate of 1 drop / second, with continuous stirring for 4h to form a precursor sol. The product was centrifuged and washed three times with anhydrous ethanol, then vacuum dried. It was then placed in a tube furnace and heated at 250℃ for 1h in air, followed by rapid switching to high-purity argon protection and heating to 400℃ for calcination for 2h. After cooling, CeO2-La2O3@TiB2 core-shell structure nano-modifier was obtained.

[0036] Step 2: Select 2500g of aluminum-lithium alloy base powder with a particle size distribution of 15-53μm and a sphericity ≥98%. The mass fraction of its components is: Li 1.2%, Cu 2.0%, Mg 0.5%, Zr 0.08%, with the remainder being Al and unavoidable trace impurities. 2500g of this aluminum-lithium alloy base powder and 30g of CeO2-La2O3@TiB2 core-shell structure nano-modifier obtained in step (1) are loaded into a vacuum mixing tank. At the same time, 14g of zinc and 1.65g of bismuth are added to the mixing tank. The mixing tank is evacuated and filled with high-purity argon gas, and then fixed on an acoustic resonance mixer. The resonance frequency is set to 60Hz and the acceleration to 60G. An intermittent pulse mode is used, running for 3 minutes and then stopping for 2 minutes to cool down. The mixture is run for a total of 15 minutes to ensure that the nano-modifier is uniformly coated on the surface of the base powder, thus obtaining a composite powder.

[0037] Step 3: Spread the composite powder obtained in step (2) evenly in a stainless steel tray, controlling the powder layer thickness to ≤2cm, and place the whole thing in a static high vacuum drying oven. Turn on the vacuum pump group to evacuate to the ultimate vacuum degree ≤1×10 -3The heating temperature was set to 80℃, and static degassing was carried out continuously at this temperature and vacuum for 4 hours. After the process was completed, the powder was allowed to cool naturally to room temperature in the furnace, then removed and sealed to obtain the degassed composite powder.

[0038] Step 4: Import the 3D model of the aerospace support to be printed into finite element analysis software for topology optimization, dividing it into different stress-bearing regions according to the stress conditions. The high-load-bearing region is designed as a fully dense solid structure; the secondary load-bearing region is designed as a BCC lattice structure with a rod diameter of 1.0 mm and a relative density of 60%; the non-load-bearing region is designed as a Gyroid minimal surface lattice structure with a wall thickness of 0.5 mm and a relative density of 20%. After completing Boolean operations, the above three regions are treated as independent entities and exported as a single 3MF multi-body assembly file.

[0039] Step 5: Load the degassed composite powder into the powder cylinder of the selective laser melting equipment. After evacuating the forming cavity, fill it with high-purity argon gas, controlling the oxygen content to ≤10ppm. Turn on the substrate heating module and set the substrate preheating temperature to 128℃. Place a blow-suction dual-channel ground-level air knife above the forming surface and control the airflow velocity between 1.5 and 2.0m / s. Import the 3MF file generated in step (4), and perform laser scanning on the fully dense solid and BCC lattice areas using solid filling parameters (laser power 280W, scanning speed 1000mm / s, scanning spacing 90μm). Perform laser scanning on the Gyroid minimal curved surface lattice areas using pure contour scanning parameters (laser power 120W, scanning speed 800mm / s). Set the powder layer thickness to 30μm, form in layers, and clean the floating powder after printing to obtain the support blank.

[0040] Step 6: Place the support blank with the substrate in a hot isostatic pressing furnace, and introduce high-purity argon gas as the pressure transfer medium. Heat to 480℃ at a heating rate of 5℃ / min and hold for 2 hours; then continue heating to 500℃, simultaneously pressurizing to 100MPa, and hold at this temperature and pressure for 3 hours. After the pressure holding is completed, control the cooling rate to ≤5℃ / min and slowly cool it to room temperature in the furnace before removing it from the furnace.

[0041] Step 7: Place the support obtained in step (6) into a vacuum heat treatment furnace equipped with high-pressure gas quenching function. After evacuation, first maintain the temperature at 480℃ for 1 hour, then gradually increase the temperature to 500℃ and continue to maintain the temperature for 1 hour. After the temperature maintenance is completed, leave the support in place, instantly fill the furnace with high-purity helium gas at a pressure of 1.0MPa, and turn on a powerful fan for rapid cooling. After the support cools to room temperature, transfer it to an aging furnace and age it at 155℃ for 22 hours. Then remove it and air-cool it to room temperature.

[0042] Step 8: Prepare a NaOH solution at 40℃ and 40g / L as the alkali solution. Seal the support obtained in step (7) in a flow cell. Use a programmable diaphragm pump to apply an alternating pulsating pressure flow of 0.1MPa and 5Hz to continuously rinse with the alkali solution for 3 minutes, and then wash with pure water. Quickly immerse the support in a deoxygenating brightening solution composed of 30vol% HNO3 and 100g / L CrO3 at room temperature for 3 minutes. After washing with pure water, immerse the support in a trivalent chromium conversion solution at room temperature for 10 minutes for passivation treatment. Finally, remove it and dry it in a 60℃ oven to obtain the final product. Example 3

[0043] A method for lightweighting aluminum-lithium alloy supports for aerospace applications using 3D printing includes the following steps: Step 1: 45g of nano-TiB2 powder with a particle size of 30-80nm was ultrasonically dispersed in 1L of anhydrous ethanol. Then, 0.15mol of cerium isopropoxide and 0.15mol of lanthanum isopropoxide were added, followed by slow dropwise addition of 0.3mol of acetylacetone as a chelating agent. The mixture was placed in a sealed three-necked flask purged with high-purity argon and magnetically stirred at 60℃ for 2h. 5mL of deionized water was diluted in 50mL of anhydrous ethanol and slowly added to the system at a rate of 1 drop / second, with continuous stirring for 4h to form a precursor sol. The product was centrifuged and washed three times with anhydrous ethanol, then vacuum dried. It was then placed in a tube furnace and heated at 250℃ for 1h in air, followed by rapid switching to high-purity argon protection and heating to 400℃ for calcination for 2h. After cooling, CeO2-La2O3@TiB2 core-shell structure nano-modifier was obtained.

[0044] Step 2: Select 2500g of aluminum-lithium alloy base powder with a particle size distribution of 15-53μm and a sphericity ≥98%. The mass fraction of its components is: Li 1.8%, Cu 3.0%, Mg 1.0%, Zr 0.15%, with the remainder being Al and unavoidable trace impurities. 2500g of this aluminum-lithium alloy base powder and 35g of CeO2-La2O3@TiB2 core-shell structure nano-modifier obtained in step (1) are loaded into a vacuum mixing tank. At the same time, 16g of zinc and 2.0g of bismuth are added to the mixing tank. The mixing tank is evacuated and filled with high-purity argon gas, and then fixed on an acoustic resonance mixer. The resonance frequency is set to 60Hz and the acceleration to 60G. An intermittent pulse mode is used, running for 3 minutes and then stopping for 2 minutes of cooling, for a total of 15 minutes, so that the nano-modifier is uniformly coated on the surface of the base powder to obtain composite powder.

[0045] Step 3: Spread the composite powder obtained in step (2) evenly in a stainless steel tray, controlling the powder layer thickness to ≤2cm, and place the whole thing in a static high vacuum drying oven. Turn on the vacuum pump group to evacuate to the ultimate vacuum degree ≤1×10 -3The heating temperature was set to 80℃, and static degassing was carried out continuously at this temperature and vacuum for 4 hours. After the process was completed, the powder was allowed to cool naturally to room temperature in the furnace, then removed and sealed to obtain the degassed composite powder.

[0046] Step 4: Import the 3D model of the aerospace support to be printed into finite element analysis software for topology optimization, dividing it into different stress-bearing regions according to the stress conditions. The high-load-bearing region is designed as a fully dense solid structure; the secondary load-bearing region is designed as a BCC lattice structure with a rod diameter of 1.0 mm and a relative density of 60%; the non-load-bearing region is designed as a Gyroid minimal surface lattice structure with a wall thickness of 0.5 mm and a relative density of 20%. After completing Boolean operations, the above three regions are treated as independent entities and exported as a single 3MF multi-body assembly file.

[0047] Step 5: Load the degassed composite powder into the powder cylinder of the selective laser melting equipment. After evacuating the forming cavity, fill it with high-purity argon gas, controlling the oxygen content to ≤10ppm. Turn on the substrate heating module and set the substrate preheating temperature to 128℃. Place a blow-suction dual-channel ground-level air knife above the forming surface and control the airflow velocity between 1.5 and 2.0m / s. Import the 3MF file generated in step (4), and perform laser scanning on the fully dense solid and BCC lattice areas using solid filling parameters (laser power 280W, scanning speed 1000mm / s, scanning spacing 90μm). Perform laser scanning on the Gyroid minimal curved surface lattice areas using pure contour scanning parameters (laser power 120W, scanning speed 800mm / s). Set the powder layer thickness to 30μm, form in layers, and clean the floating powder after printing to obtain the support blank.

[0048] Step 6: Place the support blank with the substrate in a hot isostatic pressing furnace, and introduce high-purity argon gas as the pressure transfer medium. Heat to 480℃ at a heating rate of 5℃ / min and hold for 2 hours; then continue heating to 500℃, simultaneously pressurizing to 100MPa, and hold at this temperature and pressure for 3 hours. After the pressure holding is completed, control the cooling rate to ≤5℃ / min and slowly cool it to room temperature in the furnace before removing it from the furnace.

[0049] Step 7: Place the support obtained in step (6) into a vacuum heat treatment furnace equipped with high-pressure gas quenching function. After evacuation, first maintain the temperature at 480℃ for 1 hour, then gradually increase the temperature to 500℃ and maintain it for another hour. After the heat treatment is completed, leave the support in place, instantly fill the furnace with high-purity helium gas at a pressure of 1.0MPa, and turn on a powerful fan for rapid cooling. After the support cools to room temperature, transfer it to an aging furnace and age it at 155℃ for 23 hours. Then remove it and air-cool it to room temperature.

[0050] Step 8: Prepare a NaOH solution at 40℃ and 40g / L as the alkali solution. Seal the support obtained in step (7) in a flow cell. Use a programmable diaphragm pump to apply an alternating pulsating pressure flow of 0.1MPa and 5Hz to continuously rinse with the alkali solution for 3 minutes, and then wash with pure water. Quickly immerse the support in a deoxygenating brightening solution composed of 30vol% HNO3 and 100g / L CrO3 at room temperature for 3 minutes. After washing with pure water, immerse the support in a trivalent chromium conversion solution at room temperature for 10 minutes for passivation treatment. Finally, remove it and dry it in a 60℃ oven to obtain the final product. Example 4

[0051] A method for lightweighting aluminum-lithium alloy supports for aerospace applications using 3D printing includes the following steps: Step 1: 45g of nano-TiB2 powder with a particle size of 30-80nm was ultrasonically dispersed in 1L of anhydrous ethanol. Then, 0.15mol of cerium isopropoxide and 0.15mol of lanthanum isopropoxide were added, followed by slow dropwise addition of 0.3mol of acetylacetone as a chelating agent. The mixture was placed in a sealed three-necked flask purged with high-purity argon and magnetically stirred at 60℃ for 2h. 5mL of deionized water was diluted in 50mL of anhydrous ethanol and slowly added to the system at a rate of 1 drop / second, with continuous stirring for 4h to form a precursor sol. The product was centrifuged and washed three times with anhydrous ethanol, then vacuum dried. It was then placed in a tube furnace and heated at 250℃ for 1h in air, followed by rapid switching to high-purity argon protection and heating to 400℃ for calcination for 2h. After cooling, CeO2-La2O3@TiB2 core-shell structure nano-modifier was obtained.

[0052] Step 2: Select 2500g of aluminum-lithium alloy base powder with a particle size distribution of 15-53μm and a sphericity ≥98%. The mass fraction of its components is: Li 1.8%, Cu 3.0%, Mg 1.0%, Zr 0.15%, with the remainder being Al and unavoidable trace impurities. 2500g of this aluminum-lithium alloy base powder and 50g of CeO2-La2O3@TiB2 core-shell structure nano-modifier obtained in step (1) are loaded into a vacuum mixing tank. At the same time, 20g of zinc and 2.5g of bismuth are added to the mixing tank. The mixing tank is evacuated and filled with high-purity argon gas, and then fixed on an acoustic resonance mixer. The resonance frequency is set to 60Hz and the acceleration to 60G. An intermittent pulse mode is used, running for 3 minutes and then stopping for 2 minutes of cooling, for a total of 15 minutes, so that the nano-modifier is uniformly coated on the surface of the base powder to obtain composite powder.

[0053] Step 3: Spread the composite powder obtained in step (2) evenly in a stainless steel tray, controlling the powder layer thickness to ≤2cm, and place the whole thing in a static high vacuum drying oven. Turn on the vacuum pump group to evacuate to the ultimate vacuum degree ≤1×10 -3The heating temperature was set to 80℃, and static degassing was carried out continuously at this temperature and vacuum for 4 hours. After the process was completed, the powder was allowed to cool naturally to room temperature in the furnace, then removed and sealed to obtain the degassed composite powder.

[0054] Step 4: Import the 3D model of the aerospace support to be printed into finite element analysis software for topology optimization, dividing it into different stress-bearing regions according to the stress conditions. The high-load-bearing region is designed as a fully dense solid structure; the secondary load-bearing region is designed as a BCC lattice structure with a rod diameter of 1.0 mm and a relative density of 60%; the non-load-bearing region is designed as a Gyroid minimal surface lattice structure with a wall thickness of 0.5 mm and a relative density of 20%. After completing Boolean operations, the above three regions are treated as independent entities and exported as a single 3MF multi-body assembly file.

[0055] Step 5: Load the degassed composite powder into the powder cylinder of the selective laser melting equipment. After evacuating the forming cavity, fill it with high-purity argon gas, controlling the oxygen content to ≤10ppm. Turn on the substrate heating module and set the substrate preheating temperature to 130℃. Place a blow-suction dual-channel ground-level air knife above the forming surface and control the airflow velocity between 1.5 and 2.0m / s. Import the 3MF file generated in step (4), and perform laser scanning on the fully dense solid and BCC lattice areas using solid filling parameters (laser power 280W, scanning speed 1000mm / s, scanning spacing 90μm). Perform laser scanning on the Gyroid minimal curved surface lattice areas using pure contour scanning parameters (laser power 120W, scanning speed 800mm / s). Set the powder layer thickness to 30μm, form in layers, and clean the floating powder after printing to obtain the support blank.

[0056] Step 6: Place the support blank with the substrate in a hot isostatic pressing furnace, and introduce high-purity argon gas as the pressure transfer medium. Heat to 480℃ at a heating rate of 5℃ / min and hold for 2 hours; then continue heating to 500℃, simultaneously pressurizing to 100MPa, and hold at this temperature and pressure for 3 hours. After the pressure holding is completed, control the cooling rate to ≤5℃ / min and slowly cool it to room temperature in the furnace before removing it from the furnace.

[0057] Step 7: Place the support obtained in step (6) into a vacuum heat treatment furnace equipped with high-pressure gas quenching function. After evacuation, first maintain the temperature at 480℃ for 1 hour, then gradually increase the temperature to 500℃ and maintain it for another hour. After the heat treatment is completed, leave the support in place, and instantly fill the furnace with high-purity helium gas at a pressure of 1.0MPa, and turn on a powerful fan for rapid cooling. After the support cools to room temperature, transfer it to an aging furnace and age it at 160℃ for 25 hours, then remove it and air-cool it to room temperature.

[0058] Step 8: Prepare a NaOH solution at 40℃ and 40g / L as the alkali solution. Seal the support obtained in step (7) in a flow cell. Use a programmable diaphragm pump to apply an alternating pulsating pressure flow of 0.1MPa and 5Hz to continuously rinse with the alkali solution for 3 minutes, and then wash with pure water. Quickly immerse the support in a deoxygenating brightening solution composed of 30vol% HNO3 and 100g / L CrO3 at room temperature for 3 minutes. After washing with pure water, immerse the support in a trivalent chromium conversion solution at room temperature for 10 minutes for passivation treatment. Finally, remove it and dry it in a 60℃ oven to obtain the final product. Example 5

[0059] A method for lightweighting aluminum-lithium alloy supports for aerospace applications using 3D printing includes the following steps: Step 1: 45g of nano-TiB2 powder with a particle size of 30-80nm was ultrasonically dispersed in 1L of anhydrous ethanol. Then, 0.15mol of cerium isopropoxide and 0.15mol of lanthanum isopropoxide were added, followed by slow dropwise addition of 0.3mol of acetylacetone as a chelating agent. The mixture was placed in a sealed three-necked flask purged with high-purity argon and magnetically stirred at 60℃ for 2h. 5mL of deionized water was diluted in 50mL of anhydrous ethanol and slowly added to the system at a rate of 1 drop / second, with continuous stirring for 4h to form a precursor sol. The product was centrifuged and washed three times with anhydrous ethanol, then vacuum dried. It was then placed in a tube furnace and heated at 250℃ for 1h in air, followed by rapid switching to high-purity argon protection and heating to 400℃ for calcination for 2h. After cooling, CeO2-La2O3@TiB2 core-shell structure nano-modifier was obtained.

[0060] Step 2: Select 2500g of aluminum-lithium alloy base powder with a particle size distribution of 15-53μm and a sphericity ≥98%. The mass fraction of its components is: Li 1.2%, Cu 2.0%, Mg 0.5%, Zr 0.08%, with the remainder being Al and unavoidable trace impurities. Place 2500g of this aluminum-lithium alloy base powder and 25g of the CeO2-La2O3@TiB2 core-shell structure nano-modifier obtained in step (1) into a vacuum mixing tank. Simultaneously, add 12.5g of zinc and 1.25g of bismuth to the mixing tank. Evacuate the mixing tank and fill it with high-purity argon gas. Then fix it on an acoustic resonance mixer, set the resonance frequency to 60Hz, the acceleration to 60G, and use an intermittent pulse mode with 3 minutes of operation followed by 2 minutes of cooling. Run for a total of 15 minutes to ensure the nano-modifier is uniformly coated on the surface of the base powder, thus obtaining a composite powder.

[0061] Step 3: Spread the composite powder obtained in step (2) evenly in a stainless steel tray, controlling the powder layer thickness to ≤2cm, and place the whole thing in a static high vacuum drying oven. Turn on the vacuum pump group to evacuate to the ultimate vacuum degree ≤1×10-3 The heating temperature was set to 80℃, and static degassing was carried out continuously at this temperature and vacuum for 4 hours. After the process was completed, the powder was allowed to cool naturally to room temperature in the furnace, then removed and sealed to obtain the degassed composite powder.

[0062] Step 4: Import the 3D model of the aerospace support to be printed into finite element analysis software for topology optimization, dividing it into different stress-bearing regions according to the stress conditions. The high-load-bearing region is designed as a fully dense solid structure; the secondary load-bearing region is designed as a BCC lattice structure with a rod diameter of 1.0 mm and a relative density of 60%; the non-load-bearing region is designed as a Gyroid minimal surface lattice structure with a wall thickness of 0.5 mm and a relative density of 20%. After completing Boolean operations, the above three regions are treated as independent entities and exported as a single 3MF multi-body assembly file.

[0063] Step 5: Load the degassed composite powder into the powder cylinder of the selective laser melting equipment. After evacuating the forming cavity, fill it with high-purity argon gas, controlling the oxygen content to ≤10ppm. Turn on the substrate heating module and set the substrate preheating temperature to 125℃. Place a blow-suction dual-channel ground-level air knife above the forming surface and control the airflow velocity between 1.5 and 2.0m / s. Import the 3MF file generated in step (4), and perform laser scanning on the fully dense solid and BCC lattice areas using solid filling parameters (laser power 280W, scanning speed 1000mm / s, scanning spacing 90μm). Perform laser scanning on the Gyroid minimal curved surface lattice areas using pure contour scanning parameters (laser power 120W, scanning speed 800mm / s). Set the powder layer thickness to 30μm, form in layers, and clean the floating powder after printing to obtain the support blank.

[0064] Step 6: Place the support blank with the substrate in a hot isostatic pressing furnace, and introduce high-purity argon gas as the pressure transfer medium. Heat to 480℃ at a heating rate of 5℃ / min and hold for 2 hours; then continue heating to 500℃, simultaneously pressurizing to 100MPa, and hold at this temperature and pressure for 3 hours. After the pressure holding is completed, control the cooling rate to ≤5℃ / min and slowly cool it to room temperature in the furnace before removing it from the furnace.

[0065] Step 7: Place the support obtained in step (6) into a vacuum heat treatment furnace equipped with high-pressure gas quenching function. After evacuation, first maintain the temperature at 480℃ for 1 hour, then gradually increase the temperature to 500℃ and continue to maintain the temperature for 1 hour. After the heat treatment is completed, the support remains in place, and high-purity helium gas at a pressure of 1.0MPa is instantly introduced into the furnace, and a powerful fan is turned on for rapid cooling. After the support cools to room temperature, it is transferred to an aging furnace and aged at 150℃ for 20 hours. Then, it is taken out and air-cooled to room temperature.

[0066] Step 8: Prepare a NaOH solution at 40℃ and 40g / L as the alkali solution. Seal the support obtained in step (7) in a flow cell. Use a programmable diaphragm pump to apply an alternating pulsating pressure flow of 0.1MPa and 5Hz to continuously rinse with the alkali solution for 3 minutes, and then wash with pure water. Quickly immerse the support in a deoxygenating brightening solution composed of 30vol% HNO3 and 100g / L CrO3 at room temperature for 3 minutes. After washing with pure water, immerse the support in a trivalent chromium conversion solution at room temperature for 10 minutes for passivation treatment. Finally, remove it and dry it in a 60℃ oven to obtain the final product.

[0067] Comparative Example 1: The difference between Comparative Example 1 and Example 1 is that the CeO2-La2O3@TiB2 core-shell structure nanomodifier in step 2 is replaced with an equal mass of TiB2 powder.

[0068] Comparative Example 2: The difference between Comparative Example 2 and Example 1 is that in step 6, hot isostatic pressing, the step of holding at 480°C for 2 hours was eliminated. Instead, the temperature was directly heated to 500°C at a heating rate of 5°C / min and then pressurized and held.

[0069] Comparative Example 3: The difference between Comparative Example 2 and Example 1 is that in step 6, the high-pressure helium rapid cooling (high-pressure gas quenching) in step 7 is replaced with traditional water quenching.

[0070] Comparative Example 4: The difference between Comparative Example 4 and Example 1 is that zinc and bismuth are not added to the mixing tank in step 2.

[0071] Comparative Example 5: The difference between Comparative Example 5 and Example 1 is that zinc is not added to the mixing tank in step 2.

[0072] Comparative Example 6: The difference between Comparative Example 6 and Example 1 is that bismuth is not added to the mixing tank in step 2.

[0073] Performance testing: 1. Mechanical Property Testing: Blanks were cut from the fully dense solid parts of the high-load-bearing area of ​​the supports prepared in each embodiment and comparative example, and processed into plate-shaped standard tensile specimens with a gauge length of 25 mm, a parallel section width of 6 mm, and a thickness of 2 mm. Five parallel specimens were prepared for each group. Tensile tests were conducted using a microcomputer-controlled electronic universal testing machine at a constant strain rate of 2 mm / min in an environment of 25°C and 50% relative humidity. The force-displacement curves of the specimens were recorded simultaneously. Finally, the tensile strength, specified plastic extension strength (Rp0.2, i.e., yield strength), and elongation after fracture of the specimens were obtained. After removing outliers, the arithmetic mean of the valid parallel specimens was taken. The test results are shown in Table 1.

[0074] 2. Overall Average Density Test of the Stent: The overall mass weighing-volume displacement method was used to characterize the overall lightweight effect of the stent. The dry total mass of the complete stent was weighed using an electronic analytical balance with an accuracy of 0.001g. Then, the stent was completely immersed in a standard volumetric flask containing a known volume of anhydrous ethanol at 25℃ with an accuracy of 0.1mL. The total volume of the stent was determined by the volume difference caused by the rise in liquid level. The overall average density of the stent was calculated based on "total mass / total volume". Three complete stents prepared in the same batch were tested in each group, and the final result was the arithmetic mean. The test results are shown in Table 1.

[0075] 3. Gyroid lattice structure forming pass rate test: This test employed a combination of industrial CT scanning and defect identification to verify the forming quality of the thin-walled lightweight structure. A 20μm resolution industrial CT scanner was used to scan and reconstruct the Gyroid miniature curved surface lattice region of the support layer by layer. The total number of 0.5mm thick microfilaments designed within this region was counted. Simultaneously, image recognition algorithms were used to mark the number of microfilaments with defects such as broken wires, spheroidization, collapse, slag adhesion, and lack of fusion. The forming pass rate of the lattice structure was calculated as "number of defect-free microfilaments / total number of microfilaments × 100%". Three supports from the same batch were tested in each group, and the final result was the arithmetic mean. The test results are shown in Table 1.

[0076] Table 1: Example 1 531 467 11.2 1.45 99.0 Example 2 520 452 10.3 1.48 98.5 Example 3 526 460 10.8 1.46 98.7 Example 4 535 476 11.6 1.43 99.2 Example 5 516 446 9.8 1.49 97.8 Comparative Example 1 458 392 7.2 1.52 95.1 Comparative Example 2 479 407 6.8 1.51 94.6 Comparative Example 3 517 422 4.5 1.48 62.3 Comparative Example 4 422 353 5.2 1.71 28.7 Comparative Example 5 481 412 8.1 1.63 76.3 Comparative Example 6 473 405 7.6 1.65 68.5 Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for lightweighting aerospace aluminum-lithium alloy supports using 3D printing, characterized in that, Includes the following steps: (1) The nano-TiB2 powder was ultrasonically dispersed in anhydrous ethanol, cerium isopropoxide and lanthanum isopropoxide were added, acetylacetone was added as a chelating agent, and the mixture was stirred under an inert atmosphere. Then, an aqueous ethanol solution was added dropwise and stirred continuously to form a precursor sol. After centrifugation, washing and drying, the mixture was first heated in an air atmosphere and then calcined in an inert atmosphere to obtain CeO2-La2O3@TiB2 core-shell structure nano-modifier. (2) The aluminum-lithium alloy base powder and CeO2-La2O3@TiB2 core-shell structure nano-modifier were loaded into a vacuum mixing tank, vacuumed and filled with inert gas, and then mixed in an acoustic resonance mixer using an intermittent pulse mode to make the nano-modifier uniformly coated on the surface of the base powder to obtain composite powder. (3) Spread the composite powder evenly in the tray and place it in a static high vacuum drying oven. Perform static degassing at a temperature lower than the alloy solution temperature to obtain the degassed composite powder. (4) The support was optimized by finite element analysis, and different stress bearing areas were divided. They were designed as fully dense solid structures, BCC lattice structures and Gyroid minimal surface lattice structures, and each area was exported as an independent entity as a 3MF multi-body assembly file. (5) The degassed composite powder is loaded into the powder cylinder of the selective laser melting equipment. Under the protection of an inert atmosphere, the substrate is preheated. The airflow is controlled by a blow-suction dual-channel ground-mounted air knife. The solid filling parameters are used for laser scanning of the fully dense solid and BCC lattice areas, and the pure contour scanning parameters are used for laser scanning of the Gyroid lattice areas. Layered molding is performed to obtain the support blank. (6) Place the support blank in a hot isostatic pressing furnace, and under an inert atmosphere, first heat it to a temperature below the eutectic temperature and hold it, then heat it to the solution temperature and press it to hold it, and then cool it slowly. (7) Place the support obtained after step (6) in a vacuum heat treatment furnace, evacuate and heat it stepwise, then fill it with high-pressure helium and cool it quickly, and then perform aging treatment. (8) Place the support obtained after step (7) in a flow pool, rinse it with alkaline solution under alternating pulsating pressure, then wash it with pure water, then immerse it in deoxygenation brightening solution for treatment, after washing it, immerse it in trivalent chromium conversion solution for passivation treatment, and finally dry it.

2. The lightweight 3D printing method for aerospace aluminum-lithium alloy supports according to claim 1, characterized in that, In step (1), the molar ratio of cerium isopropoxide to lanthanum isopropoxide is 1:

1.

3. The lightweight 3D printing method for aerospace aluminum-lithium alloy supports according to claim 1, characterized in that, In step (2), the aluminum-lithium alloy base powder includes the following components: Li 1.2-1.8wt%, Cu 2.0-3.0wt%, Mg 0.5-1.0wt%, Zr 0.08-0.15wt%, balance being Al and unavoidable trace impurities.

4. The lightweight 3D printing method for aerospace aluminum-lithium alloy supports according to claim 1, characterized in that, In step (2), the aluminum-lithium alloy base powder has a particle size distribution of 15-53 μm and a sphericity of ≥98%.

5. The lightweight 3D printing method for aerospace aluminum-lithium alloy supports according to claim 1, characterized in that, In step (2), the mass ratio of aluminum-lithium alloy base powder to CeO2-La2O3@TiB2 core-shell structure nanomodifier is 500:(5-10).

6. The lightweight 3D printing method for aerospace aluminum-lithium alloy supports according to claim 1, characterized in that, In step (2), zinc and bismuth are also added to the mixing tank.

7. A method for lightweighting aerospace aluminum-lithium alloy supports using 3D printing according to claim 6, characterized in that, In step (2), the amount of zinc added is 0.5 to 0.8 wt% of the aluminum-lithium alloy base powder; the amount of bismuth added is 0.05 to 0.1 wt% of the aluminum-lithium alloy base powder.

8. A method for lightweighting aerospace aluminum-lithium alloy supports using 3D printing, as described in claim 1, characterized in that... In step (5), the substrate preheating temperature is 125-130°C.

9. A method for lightweighting aerospace aluminum-lithium alloy supports using 3D printing, as described in claim 1, characterized in that... In step (7), the aging treatment temperature is 150-160℃ and the aging treatment time is 20-25h.

10. A method for lightweighting aerospace aluminum-lithium alloy supports using 3D printing according to claim 1, characterized in that, In step (8), the deoxygenated light-emitting liquid is composed of HNO3 and CrO3.

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