Effects of indenter geometry and material properties on the correction factor of Sneddon's relationship for nanoindentation of elastic and elastic-plastic materials

Finite element simulations of indentations on elastic and elastic-plastic materials have been performed to systematically study the effects of indenter geometry and mechanical properties, namely Poisson's ratio and the E/sigma(y) ratio, on the correction factor for Sneddon's equation used for analysis of nanoindentation data. Two indenter geometries, namely conical and Berkovich indenters, have been considered. It has been shown that the first-order correction for conical indentation on elastic materials previously developed by Hay et at. [Hay JC, Bolshakov A, Pharr GM. J Maier Res 1999;14:2296-305] can be applied only to conical indentation of elastic deformation-dominated materials but not to Berkovich indentation. A new general relationship for the estimation of the correction factor for Berkovich indentation is proposed based on the finite element simulation results. This relationship gives a better estimation of correction factor for Berkovich indentations on both elastic and elastic-plastic materials. (C) 2007 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.