Review of passivity and electrochemical properties of nanostructured stainless steels obtained by surface mechanical attrition treatment (SMAT): trend and progress

Surface nanocrystallization provides the opportunity to produce gradient-structured metallic materials with improved properties. Several attempts have been made to produce nanostructured stainless steel (SS), along with the study of the resultant corrosion resistance. However, the current knowledge is insufficient to address the corrosion mechanism and the possible ways of enhancing the corrosion resistance after surface treatment. The present work reviews the past significant works on the effect of surface treatment by surface mechanical attrition treatment (SMAT) method as well as its processing parameters on the corrosion properties of SS. The corrosion resistance of nanostructured SS is influenced by the extent of grain refinement, compactness, and homogeneity of the passive film, Cr content, grain boundary structure, composition, and alloying elements. In addition, the resulting corrosion properties can be controlled by choosing the right processing parameters during treatment. Progress on the corrosion behavior of nanostructured steels was summarized and new avenues for further research and developments are proposed.