The role of nanostructure in pitting of Al-Alloys

Al-alloys are inherently susceptible to localised corrosion owing to their heterogeneous microstructures. In this work, we adopt a bottom-up approach to quantify the critical microstructural feature size is capable of triggering a cascade of pitting events and eventual degradation of corrosion resistance. This is accomplished via exploiting the well characterised hardening response in a model alloy, Al-1.1Cu-1.7Mg (at%), for which pitting resistance of the alloy was tracked with ageing time and hence microstructural evolution. Corrosion performance and microstructural characterisation were carried out using combination of electrochemical testing, coupled with high resolution scanning transmission electron microscopy (HRSTEM) and atom probe tomography (APT). We propose