The effects of grain refinement and deformation on corrosion resistance of passive film formed on the surface of 304 stainless steels

Abstract The nano/ultrafine grained stainless steel promoted the form of more deformation nanotwins and inhibited dislocation slip and strain induced α′-martensite transformation during deformation compared with coarse grained stainless steel. The diffusivity of the point defects in passive film in coarse grain stainless steel was lower than that in nano/ultrafine one. The corrosion resistance of nano/ultrafine grained stainless steel was improved by reducing content of strain induced α′-martensite. Moreover, the donor and acceptor densities in passive film formed on the stainless steel increased due to more strain induced α′-martensites and more chloride ions. Fewer strain induced α′-martensites and more nanotwins in nano/ultrafine grained stainless steel improved its corrosion resistance.