Nano-scale dissolution phenomena in Al–Cu–Mg alloys

Localized corrosion of aluminum alloys is a major issue worldwide and in spite of decades of work, several questions still remain unresolved. In this study we focus on key issues in the context of localized corrosion of Al–Cu–Mg/Al–Mg–Cu alloys that have not been adequately addressed. By careful electrochemical exposure along with high-resolution electron microscopy, we reveal that microstructural features down to a few nanometers in size can behave as unique electrochemical entities. In addition, not only is this critical to emerging damage accumulation models, but we also reveal that significant dissolution can occur at potentials below the breakdown potential of the bulk alloy. This work has potentially wide consequences in the interpretation of Al alloy corrosion and alloys design for corrosion resistance.