Surface and sub-surface damage of 0.20 wt% C-martensite during three-body abrasion

Three-body abrasive wear of 0.2 wt%-C martensitic steel was conducted in a dry-sand rubber wheel test apparatus following non-standard G65-16 test procedure. The specific wear rate (SWR) of the experimental alloy was compared against other microstructures of equivalent hardness. It was observed that the SWR of the experimental alloy follows the Type-1 category, in which hardness plays a major role in controlling wear. The wear mechanism was found to be predominantly micro-cutting followed by furrow and pitting. The deformation of microstructure along the depth from the wear surface was studied by Focused Ion Beam(FIB) milling-Transmission Electron Microscopy(TEM) and X-ray diffraction (XRD), following conventional and modified Williamson-Hall and Warren-Averbach analysis. The crystallographic study reveals limited plastic deformation of martensite (alpha') within a shallow depth from the worn surface, as indicated by marginal change in the character and density of dislocation, which results in higher SWR owing to the inablility of the alpha'-phase to accommodate the strain energy of abrasion.