In-situ EBSD investigation of thermal stability of a 316L stainless steel nanocrystallized by Surface Mechanical Attrition Treatment

•In-situ EBSD is used to study the thermal stability of a SMATed nanocrystalline steel.•Oxidation is detected at high temperatures and degrades the indexation quality.•Ionic polishing is carried out to remove the oxidized layer and reveal the grains.•No obvious grain changes indicate a good thermal stability of the gradient microstructure. In-situ Electron BackScatter Diffraction (EBSD) was used to study the thermal stability of a stainless steel nanocrystallized by Surface Mechanical Attrition Treatment (SMAT). A grain size gradient was generated after SMAT from the surface to the interior of the specimen. Observations at different temperatures were performed to study the thermal stability of the gradient microstructure. During the investigation, oxidation was detected which greatly affected the indexation quality especially for high temperatures. After an ionic polishing, the grains could be properly revealed. No obvious microstructure changes were highlighted up to 720 °C, which indicated a good thermal stability of the nanocrystalline grains.