Correlation of intergranular corrosion behaviour with microstructure in Al-Cu-Li alloy

The IGC behaviour, OCP and microstructure of AAl460 (Al-3.12Cu-2.14Li-0.12Sc-0.122r, in wt.%), following HT1 (heat treatment without predeformation) and HT2 (heat treatment with predeformation) tempers were investigated. Both delta' (Al3Li) and T-1 (Al2CuLi) phases were precipitated within grains during heat treatment, while T-1 phase also precipitated in the vicinity of grain boundaries. The evolution of inter-and intra-granular microstructures in AA1460 influenced the local and global electrochemical characteristics, which in turn influenced the temper dependent corrosion morphologies of AA1460. A correlation between OCP and corrosion mode was proposed, which may be used to compare the IGC sensitivity of AA1460 with different tempers.