Insight into the localized strain effect on micro-galvanic corrosion behavior in AA7075-T6 aluminum alloy

Micro-galvanic corrosion behaviors between two primary intermetallic particles (Mg2Si, α(Al-Fe-Cu)) and the Al matrix were investigated under elastic and plastic deformations in AA7075-T6. Strain localization was mainly concentrated within Mg2Si and at the interface of α(Al-Fe-Cu)/Al matrix under deformations. The experimental Volta potential differences between Mg2Si, α(Al-Fe-Cu) and Al decreased by 0–16 mV and 2–27 mV in the elastic stage but increased by 0–39 mV and 0–81 mV in the plastic stage, which were consistent with the calculation results. Accordingly, the pitting corrosion resistance was improved under elastic deformation but deteriorated under plastic deformation.