| Abstract: | The exfoliation corrosion and stress corrosion cracking behaviour of an unrecrystallized sheet of the Al-Li-Cu-Mg-Zr alloy 8090-T6 was investigated. The material was highly susceptible to exfoliation corrosion in the 96 h EXCO test, whereas the intermittent salt spray test (MASTMAASIS test) revealed only a slight degree of exfoliation. The stress corrosion cracking behaviour was investigated in 3.5% NaCl solution under constant load, constant deformation, and slow strain rate conditions. Tests under constant load were also performed in an inhibited and acidified 2% NaCl solution according to the German standard LN 65666. In these accelerated tests the investigated alloy was found to be not susceptible to stress corrosion cracking in the rolling direction. The slow strain rate tests revealed a great scattering of the relative fracture energy with decreasing strain rates. This scatter is probably caused by pits acting as crack nuclei thus giving rise to scatter of the ductility. |
