Comprehending the coupled effect of multiple microstructure defects on the passive film features and pitting behavior of UNS S32101 in simulated seawater

Abstract

The effect of cold deformation on the passive film features and pitting behavior of DCR2101 (direct cold rolled UNS S32101 billet) in simulated seawater was investigated by considering the coupled effect of multiple microstructure defects. Enhancive SIM (strain-induced martensite) and high-density dislocation within finer microbands deteriorated the stability and thickness of the passive film. Defects stimulated cation vacancy formation at the matrix/film interface. Pitting behavior with less than 70% deformation was mainly determined by finer microbands, continuous/twisted Cr2N and microgalvanic effects, whereas pitting behavior with 70% deformation was primarily dominated by anodic SIM with {111}<110> and {112}<110> components, originating from B, G and G/B of parent austenite. The dominating inducements of anti-pitting deterioration as well as different pitting behaviors were identified.