Abstract
Relation of microhardness to the indentation depth has been experimentally investigated for two single crystalline materials of silicon and aluminum. For the case of silicon, the microhardness is strongly affected by phase transition and dislocation emission. The indent-induced phase transition gets over to the diamond structure with the different crystallographic orientation from the bulk after unloading. Increase of microhardness at the depth less than about 1.5μm is observed at the case of aluminum. It is found that onset of the increase is dependent on the surface roughness and surface work-hardening.
