What Are The Applications Of Deep Processing Technology For Aluminum Alloys in Aerospace?

一, Precision molding technology: high-precision manufacturing of complex structures
1. Superplastic Forming and Diffusion Bonding (SPF/DB)
SPF/DB technology achieves the integral forming of complex thin-walled structures by controlling the superplasticity of aluminum alloys at high temperatures (450-550 ℃) and low strain rates (10 ⁻³ -10 ⁻⁴⁴⁻¹). For example, 7475 aluminum alloy can achieve an elongation of 600% at 520 ℃ and a strain rate of 10 ⁻³ s ⁻¹, and is used to manufacture complex curved structures such as aircraft inlet lips and satellite antenna reflectors. This technology integrates multiple parts into a whole, reducing the number of welds, improving structural reliability, and reducing weight by 30% -50%.
2. Rheological extrusion forming
For irregular parts such as aircraft engine blades, rheological extrusion technology achieves semi-solid forming of aluminum alloys by controlling the extrusion speed (5-10mm/s) and mold temperature (400-450 ℃). For example, A356 aluminum alloy can be extruded in a semi-solid state with a liquid phase ratio of 40% -60%, resulting in a fine grain structure with a grain size of less than 50 μ m. The tensile strength can be increased to 320 MPa, and the elongation can reach 12%, meeting the high-temperature service requirements of engine blades.
3. Precision forging
Aircraft aluminum alloy forgings must meet the requirements of high strength and high fatigue life. For example, 7050-T7451 aluminum alloy undergoes isothermal forging (420 ℃, strain rate 0.1s ⁻¹) process, resulting in uniform streamline distribution and fatigue life of 2 × 10 ⁶ cycles, which is 40% higher than traditional forging. This technology is widely used in key load-bearing components such as aircraft landing gear and engine shaft.
二, Surface Strengthening Technology: Performance Enhancement in Extreme Environments
1. Laser shock peening (LSP)
LSP technology induces plasma shock waves through high-energy pulsed lasers (10 ⁹ W/cm ²) to introduce residual compressive stress layers on the surface of aluminum alloys. For example, after LSP treatment of 2024-T3 aluminum alloy, the residual compressive stress on the surface reaches -600MPa, and the fatigue crack propagation rate is reduced by 70%, which is suitable for fatigue sensitive parts such as aircraft wing skin and fuselage frame.
2. Micro arc oxidation (MAO)
MAO technology generates a ceramic oxide film on the surface of aluminum alloy, with a thickness of 50-100 μ m and a hardness of HV1200-1500. For example, after MAO treatment, the resistance rate of 2219 aluminum alloy to atomic oxygen corrosion is reduced to 0.005mg/cm ² · h, which is two orders of magnitude higher than anodizing and suitable for outer surface protection of spacecraft.
3. Cold spray repair
For the local damage of aluminum alloy parts, cold spraying technology deposits aluminum alloy powder on the surface of the substrate through supersonic airflow (300-1200m/s) to form a dense coating. For example, after cold spraying repair of cracks in 7075-T6 aluminum alloy, the bonding strength reaches 45MPa, and the repair efficiency is three times higher than traditional welding, making it suitable for rapid on-site repair of aircraft landing gear and engine blades.
三, Additive Manufacturing Technology: Free Manufacturing of Complex Structures
1. Laser Selective Melting (SLM)
SLM technology uses high-energy lasers (200-400W) to melt aluminum alloy powder layer by layer, achieving direct manufacturing of complex structures. For example, a satellite bracket made of AlSi10Mg alloy powder has a density of 99.8%, a tensile strength of 420MPa, an elongation of 8%, a weight reduction of 25% compared to traditional castings, and a 50% increase in design freedom.
2. Arc Additive Manufacturing (WAAM)
WAAM technology uses an arc heat source (20-30kW) to melt aluminum alloy welding wire, with a deposition efficiency of 5-10kg/h. For example, the rocket tank frame made of 7075 aluminum alloy through WAAM has an interlayer bonding strength of 90% of the base material and a fatigue life of 1 × 10 ⁶ cycles, meeting the rapid manufacturing needs of carrier rockets.
3. Post processing of additive manufacturing
Additive manufacturing of aluminum alloys requires the elimination of internal pores through hot isostatic pressing (HIP). For example, after HIP treatment (500 ℃, 150MPa, 4h) on SLM formed 2024 aluminum alloy, the density increased to 99.9% and the fatigue limit increased from 180MPa to 240MPa, meeting the requirements of aviation main load-bearing structures.
四, Composite material integration technology: a leapfrog improvement in performance
1. Aluminum based composite materials (AMCs)
By adding reinforcing phases such as silicon carbide (SiC) and aluminum oxide (Al ₂ O3) to aluminum alloys, the material properties are significantly improved. For example, SiC/2124 composite material has a tensile strength of 650MPa and an elastic modulus of 90GPa, which is 30% higher than the base aluminum alloy. It is used to manufacture high-temperature components such as aircraft wing leading edges and engine blades.
2. Fiber metal laminates (FMLs)
FMLs are composed of alternating layers of aluminum alloy sheets and fiber prepreg. For example, Glare laminates (made of glass fiber/2024 aluminum alloy) have a 20% increase in strength and a 5-fold increase in fatigue resistance compared to aluminum alloys. They have been applied to Airbus A380 fuselage panels, reducing weight by 15% -20%.
3. Nanocrystalline aluminum alloy
The nanocrystalline aluminum alloy prepared by severe plastic deformation (such as equal channel angular pressing) has a grain size of less than 100nm, a yield strength of 800MPa, and an elongation of 10%. For example, the fatigue crack propagation rate of nanocrystalline 7075 aluminum alloy is reduced by 80% compared to coarse-grained materials, making it suitable for high-pressure compressor blades in aircraft engines.