Influence of surface-roughness on indentation size effect

During nanoindentation of a material with a naturally rough-surface, a flattening of the rough-surface is additionally accomplished compared to nanoindentation on a flat surface. By separating analytically the work expended to flatten the rough-surface and to deform the flattened surface, we develop here a new rough-surface indentation size effect (ISE) model. This new model is applied to nanoindentation results for three Ni samples of different surface-roughness and the applicability of the model is discussed in terms of a critical contact depth for the surface-roughness effect on ISE.