Local Corrosion Behaviors of LY6 Aluminum Alloy in CI~- Environment

Local corrosion behaviors of LY6 aluminum alloy after natural aging treatment in solution containing Cl~-,such as pitting corrosion, intergranular corrosion, exfoliation corrosion (EXCO) and stress corrosion cracking (SCC), were studied as well as their mechanisms and correlation. LY6 aluminum alloy is susceptible to pitting corrosion, intergranular corrosion,EXCO and SCC in the testing environment, which is essentially due to the existence of second phases, such as S phase (Al_2CuMg) , θ phase (CuAl_2 ) and MnAl6 phase. The exfoliation of alloy happens from original pitting to intergranular corrosion and with cooperation of stress. By constant load tensile test and fracture analysis, SCC of LY6 aluminum alloy is owing to the anodic dissolution effect.