Abnormal selective dissolution by the partial recrystallization in a plastically deformed austenitic stainless steel

Abstract The influence of microstructure evolution during ageing on the corrosion behavior of deformed Super304H stainless steel was studied. For deformed specimen after ageing, an abnormal dissolution current peak existed in the potentiodynamic polarization curve at early passivation when surface passive film was thin and sensitive to galvanic corrosion, which terminated as passivation proceeded to a complete and compact film. Partial recrystallization during ageing formed uneven microstructure where the recrystallized coarse grains were selectively dissolved due to their inferior corrosion resistance compared to the residual nano-grains. Increased recrystallization region in the over-deformed state intensified the selective dissolution to a higher current peak.