Experimental investigations of the sneddon solution and an improved solution for the analysis of nanoindentation data

The Sneddon solution, as it is implemented in the Oliver-Pharr method, deviates from the indentation experimental data in a manner which depends on both the indenter angle and the Poisson ratio of the sample. These effects are demonstrated experimentally by performing indentations in tungsten and aluminum using a cube-cube corner indenter where the effects are exacerbated by the small indenter angle. The first objective was to experimentally support and validate an approximate analytical solution in conjunction with finite element simulations which illustrate the Poisson ratio and indenter angle effects. Second, a review of data analysis procedures is presented which leads to a better understanding of the systematic errors which percolate through in the measurement of Young's modulus and hardness.