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

Highlights: • Strain mainly concentrated within Mg₂Si particles and at Al/α(Al-Fe-Cu) interface. • Volta potentials of Mg₂Si and α(Al-Fe-Cu) decreased slightly in the elastic stage. • Volta potentials of Mg₂Si and α(Al-Fe-Cu) increased in the plastic stage. • The pitting corrosion resistance was improved under elastic deformation. • The pitting corrosion resistance was degraded under plastic deformation. 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.