Insights into the electrochemical response of a partially recrystallized Al-Mg-Si alloy and its relationship to corrosion events

The degradation of ultra-fine grained aluminum alloys involves multiple localized corrosion mechanisms at once which make its understanding complex. Here we investigate the electrochemical response of a partially recrystallized ultra-fine grained AA6061 alloy after a low-temperature post-aging treatment. Our results show that the anodic current density, the severity of the filiform corrosion along the shear direction, and the intergranular corrosion are significantly influenced by the precipitation within the shear bands, being the highest at peak aging. Also, passivation is enhanced but the passive film is less stable after ECAP regardless of the low- temperature post-aging treatment. because of the high density of dislocation, precipitates, and grain boundary in the extruded material. •The electrochemical response of UFG AA6061 are influenced by the precipitation within the shear bands after ECAP and post-aging treatment.•The severity of the anodic dissolution along the shear direction, and the intergranular corrosion are the highest at peak aging.•Passivation is enhanced after ECAP regardless of the post-aging treatment but the passive film is less stable.