Toward the development of continuum single-crystal contact mechanics analyses to microindentation experiments

Abstract

This investigation concerns three-dimensional continuum crystal plasticity finite element simulations of spherical and pyramidal (Berkovich) indentation experiments performed in fcc single and polycrystals. Our fundamental purpose is to examine and extend the correlations between hardness and the uniaxial stress–strain characteristics found from the seminal work by Tabor and from contact mechanics analyses to the case of single-crystal micro/nanoindentations. In doing so, isotropic equivalents to the single-crystal responses are examined in conjunction with the concept of Tabor’s equivalent (representative) indentation stress. The paper also focusses in the self-similar responses of two types of crystals, illustrating influence of the critical resolved shear stress for dislocation gliding on the development of a transitional elasto-plastic regime and a fully-plastic response. A discussion is then given on the potential applicability of the present framework to the analysis of indentation size effects. Clear evidence is finally provided supporting conception that single-crystal sharp and spherical indentations render similar responses at a sufficient penetration of the tip.