The influence of grain structure on the corrosion behaviour of 2A97-T3 Al-Cu-Li alloy

In the present study, the corrosion behaviour of 2A97-T3 Al-Cu-Li alloy is investigated. The corrosion propagation path is characterized with electron backscatter diffraction (EBSD) and transmission Kikuchi diffraction (TKD), and correlated to local grain structure and the distribution of T1 (Al2CuLi) and TB (Al7Cu4Li) phase precipitates in the alloy. Localized corrosion occurs preferentially along the subgrain boundaries within unrecrystallized grains of this partially recrystallized alloy. The grain stored energy plays a more decisive role in corrosion propagation compared to T1 phase precipitate. The grain boundaries decorated by TB phase precipitates exhibit relatively low susceptibility to corrosion.