Aircraft skin is a layer of aluminum alloy that keeps the shape of aircraft and makes it have good aerodynamic characteristics.

Edit the working conditions and performance requirements of this paragraph. The function of aircraft skin is to keep the shape of aircraft and make it have good aerodynamic characteristics. After the skin bears aerodynamic force, it transfers the force to the connected fuselage wing frame, and the force is complicated. In addition, the skin is in direct contact with the outside world, so it requires not only high strength and plasticity of skin materials, but also smooth surface and high corrosion resistance.

LY 12 is generally used as the material.

Technical requirements: σb =390~4 10MPa, σ0.2 =255~265MPa, δ 5 ≥ 15%.

The technological process includes plate rolling → annealing → cleaning → solution treatment → stretch forming → aging → mechanical processing → surface treatment.

The heat treatment process is 495~503℃, water cooling for 0.4h and room temperature for more than 96h.

Ultra-hard aluminum alloy, aluminum-zinc-magnesium-copper series, 2024, etc., are mainly used for civil aircraft skin. Some are composite materials, as well as titanium alloys and alloy steels. The current development trend is to increase the proportion of composite materials and titanium alloys. Like Boeing 787, about half of it is carbon fiber composite. And the 777 synthesis is 1 1%. Old 747 Cai 1%. Generally, it is aluminum alloy, but there are also alloy steels, such as MIG -25, which are mainly used for heat protection during hypersonic flight. As for titanium alloy skin, SR-7 1 is useful. But now the plane is becoming a composite material, using carbon fiber composite materials.