A critical examination of the fundamental relations used in the analysis of nanoindentation data

Methods for analyzing nanoindentation load-displacement data to determine hardness and elastic modulus are based on analytical solutions for the indentation of an elastic half-space by rigid axisymmetric indenters. Careful examination of Sneddon{close_quote}s solution for indentation by a rigid cone reveals several largely ignored features that have important implications for nanoindentation property measurement. Finite element and analytical results are presented that show corrections to Sneddon{close_quote}s equations are needed if accurate results are to be obtained. Without the corrections, the equations underestimate the load and contact stiffness in a manner that leads to errors in the measured hardness and modulus, with the magnitudes of the errors depending on the angle of the indenter and Poisson{close_quote}s ratio of the half-space. First order corrections are derived, and general implications for the interpretation of nanoindentation data are discussed. {copyright} {ital 1999 Materials Research Society.}