4D microstructural characterization of corrosion and corrosion-fatigue in a Ti–6Al–4V / AA 7075-T651 joint in saltwater environment

Abstract

Abstract Dissimilar alloy couples are susceptible to environmentally assisted damage owing to the presence of crevices and potential difference between the constituent alloys. In this study, x-ray computed tomography has been employed to non-destructively study the corrosion behavior of a dissimilar alloy fastener-plate couple (AA7075-T651/Ti–6Al–4V) in a 3.5\xa0wt% NaCl environment. Following this, the specimen was subjected to corrosion fatigue and post fracture failure analysis was performed. The precise locations of corrosion pitting damage in the specimen were studied with respect to corrosion time. Microstructural factors that contribute to crack initiation were identified using a correlative microscopy-based approach and are discussed.