Characterization of Frictional Stressed White Etching Layers out of Cutting Tools by Means of Transmission Electron Microscopy (TEM)

Abstract

Abstract White etching layers have been found at the surface of water submerged cutting tools and have been analyzed by transmission electron microscopy (TEM). For high resolution investigations, samples had been prepared by sandwich and lift-out preparation. The investigations have shown a grain refinement at the surface. The origin martensitic microstructure is transferred into a nano-crystalline microstructure of domain sizes down to 50 nm. The crystallographic structure was identified by electron diffraction as martensite. Moreover, the depth of the grain-refined layer is not as deep as the white etching phenomenon as it is found in conventional optical micrographs. Thus, the white etching layer is not only caused by the grain refinement.