CORROSION BEHAVIOUR OF Al-Li-Cu-Mg ALLOY 8090-T651

Using accelerated laboratory tests the AI-Li-Cu-Mg alloy 8090-T651 was found to be susceptible to intergranular and exfoliation corrosion. In the long transverse direction the material was proved to be resistant against stress corrosion cracking, whereas in the short transverse direction a susceptibility to stress corrosion cracking was ascertained. In constant load and constant strain tests a threshold stress below 50 MPa was determined. The stress corrosion crack path was intergranluar. On the SCC fracture surfaces a brittle fracture mode and attacked grain and subgrain boundaries were observed