Effects of retained austenite stability on the electrochemical activity and stress corrosion cracking of ultrafine bainite steel in a marine environment

This work investigated the effects of retained austenite (RA) stability on electrochemical activity and stress corrosion cracking (SCC) of ultrafine bainitic (UFB) steel in marine environment. Under pre-strained condition, RA underwent transformation and strain-induced martensite formed, which increased the number of crystal defects in steels. Moreover, the micro-galvanic effect and the high dislocation density in the multiphase complex structure increased the electrochemical activity, which further promoted the SCC susceptibility and crack initiation of the pre-strained steels. However, high pre-strain promoted the transformation of highly stable film-like retained austenite and formed plastic lath martensite, which relatively delayed the crack propagation.