Computational study of nanoindentation on an elastoplastic solid with an interface parallel to the indentation direction

Abstract

Nanoindentation has been developed to map the local mechanical properties of heterogeneous solids. Although the local properties at the indentation site are required for mapping, the map resolution worsens because of the deformation of other components surrounding the indentation, such as the grains encompassing an indentation in heterogeneous polycrystals. To quantify the transitional change in a P-h curve with an increase in h, where P is the indentation load and h is the indentation penetration depth, this study proposes weight functions. These functions aim to quantify point-sharp nanoindentations on a circular column embedded in a matrix, which has an interface parallel to the indentation direction. The mechanical properties of the column can be accurately evaluated by extrapolating the weight functions to an indentation depth of zero, which improves the map resolution. When comparing the effects of the parallel and vertical interfaces, the impact of the vertical interface on the P-h curve is more significant than that of the parallel interface. This suggests that the correlation between the heterogeneity of local mechanical properties and the microstructure observed at the surface is controversial.