Processes of Deformation-induced Martensite Transformation and Microstructure Refinement of 316L Stainless Steel during Surface Mechanical Rolling Treatment postprint

Abstract: A gradient and nanostructured (GNS) surface layer was formed on a 316L stainless steel sample by using surface mechanical rolling treatment (SMRT). The effect of SMRT on the evolution of phase composition and microstructure was studied of the GNS surface layer. The results show that deformation- induced martensite transformation occurs in the surface layer after SMRT, and the martensite amount increases with the increasing penetration depth of SMRT. The microstructural refinement mechanism includes subsequently the formation and interaction of various dislocations, deformation twinning, deformation- induced martensite transformation, and martensite refinement. Finally, nanostructure with mostly martensite and a mean grain size of ca. 55 nm was achieved in the topmost surface layer of the 316L sample.