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

The IGC behaviour, OCP and microstructure of AA1460 (Al-3.12Cu-2.14Li-0.12Sc-0.12Zr, in wt.%), following HT1 (heat treatment without predeformation) and HT2 (heat treatment with predeformation) tempers were investigated. Both δ′ (Al3Li) and T1 (Al2CuLi) phases were precipitated within grains during heat treatment, while T1 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.