Indentation analysis of sub-surface deformation in ductile materials after solid particle erosion

Sub-surface deformation of several industrially important Ni, Co, and Fe-based wrought alloys and pure Cu, Ta, and Ni was analyzed. All samples were eroded by hard Al2O3 particles at a 90° impact angle and 40 m s−1. The deformation and load–displacement response within the plastically deformed zone below the eroded surface were measured by using a nanoindentation test system. Results from the indentation test were used to determine the effect of materials hardness on the restitution coefficient and to compare the amount of energy that is transferred into plastic deformation during particle impact. All materials showed a load–unload hysteresis, which represents a measure of the amount of energy dissipated into plastic deformation during indentation. Also, elastic recovery of the indenter was significantly higher near the eroded surface than away from the eroded surface. For all materials, a logarithmic-type relationship was observed between hardness and restitution coefficient.