Stress-Corrosion and Corrosion-Fatigue Properties of Surface-Treated Aluminium Alloys for Structural Applications

Aluminium alloys are materials of choice for structural applications with remarkable mechanical and corrosion properties but prone to premature failure under the combined action of stress and corrosive environment. Over the years, several efforts including surface modifications and thermomechanical treatments have been made to address this shortcoming. The present work reviews the corrosion, stress corrosion cracking (SCC), and corrosion fatigue (CF) behaviour of nanostructured Al alloys especially the Al–Mg (5xxx-series) and Al–Zn–Mg (7xxx-series), after surface modifications. To a large extent, the SCC behaviour of Al alloys could be influenced by the microstructure, heat treatments, stress, pre-strain, alloy compositions, and environments. The CF properties of surface-modified Al alloys were reviewed with a view to finding a relation between the nanostructured Al alloys and their aftermath corrosion fatigue properties. The fatigue behaviour of Al alloys can be influenced by the corrosion behaviour via various mechanisms including hydrogen embrittlement, prompt crack growth in aggressive environment, and crack initiation at pits. The strengthening mechanisms in nanostructured Al alloys are also briefly explained. For further study, some insights are then provided to avail the readers on options for future research.