Mechanical characterization and interfacial enzymatic activity of AISI 316L stainless steel after surface nanocrystallization

Shot peening is a well-known surface severe plastic deformation treatment widely used for improving the mechanical performance of metallic materials. It was revealed that applying severe shot peening, which is characterized by high kinetic energy, has an effective role in surface nanocrystallization of metallic materials. In this study, firstly the effects of different shot peening treatments using conventional and severe parameters were investigated on the mechanical properties and fatigue behavior of the 316L stainless steel. Microstructural analyses and measurements of grain size, microhardness, residual stresses, surface roughness, surface wettability as well as fatigue tests were performed. Then for the first time, the interfacial enzymatic activity of Laccase multicopper oxidoreductase enzyme was investigated on the nanostructured and rough surface of the shot peened samples. The surface nanostructured 316L samples exhibited considerable improvement in terms of mechanical properties and fatigue behavior and also showed increased enzymatic activity. These results can promote the application of surface nanocrystallized samples for biochemical and biomedical applications.