A highly efficient and flexible route to study multi-scale microstructures in steels via BSE observation

Abstract Microstructural characterization is essential and critical in materials development and application. Traditionally, SEM and TEM are used to characterize multi-scale microstructures of grains and precipitates in steels, which are tedious and highly dependent on the specimen quality. Here, we report a new route that utilizes the high resolution and efficiency of SEM, using the SEM-BSE observation of the specimen with flexible sampling methods. The approach efficiently reveals the microstructures usually investigated using EBSD and TEM, i.e., severely deformed grains and microstructures downing to nanoscale in shot-peened stainless steel, and the complex precipitations in heat resistant steel. Moreover, the sampling is flexible, that a well-polished surface, i.e., TEM thin foil and SEM specimens after electrolytic polishing or ion milling, can be used for BSE observation. The route opens a new way to characterize the microstructures at high efficiency.