Role of microstructure in corrosion initiation of a highly-deformed AA2024 wire

Stable pits with H2 evolution preferentially occurred in an annular region surrounding the centre of AA2024 wire. The grain size and intermetallic particles (α-phase, Al7Cu2Fe, Al2CuMg, Mg2Si, Al2Cu) distributions were the same for both regions. However, the annulus had mixed orientations, high angle grain boundaries and microshear bands while the centre was dominated by [111] orientations and low angle grain boundaries with the latter being responsible for its passive nature.