Material structure of aluminum alloy

Pure aluminum has a low density (ρ=2.7 g/cm³), about 1/3 of iron, and has a low melting point (660°C). Aluminum is a face-centered cubic structure, so it has a high plasticity (δ: 32~40%, ψ: 70~90%), easy to process, can be made into various profiles and plates, and has good corrosion resistance. However, the strength of pure aluminum is very low, and the annealing state σb value is about 8 kgf/mm², so it is not suitable as a structural material. Through long-term production practices and scientific experiments, people gradually strengthened aluminum by adding alloying elements and applying heat treatment, which resulted in a series of aluminum alloys. The alloy formed by adding certain elements can have higher strength while maintaining the advantages of pure aluminum, and the σb value can reach 24 to 60 kgf/mm², respectively. This makes its "specific strength" (ratio of strength to specific gravity σb / ρ) better than many alloy steels, becoming an ideal structural material, widely used in machinery manufacturing, transportation machinery, power machinery and aviation industry, aircraft fuselage , skins, compressors, etc. are often made of aluminum alloy to reduce their own weight. The use of aluminum alloy instead of steel plate welding can reduce the structural weight by more than 50%.