Effect of the friction between a point-sharp indenter and an indented elastoplastic solid on the load and depth sensing indentation

Abstract The effect of the friction coefficient μ between a point-sharp indenter and an indented elastoplastic solid on nanoindentation behavior is examined quantitatively in a wide range of μ with varying the elastoplasticity of the solids through the numerical analysis of nanoindentations simulated with the finite element method. The mean pressure under an indentation significantly increases with an increase in μ. In addition, the increase is emphasized by the increase in the plasticity of the deformation under the frictional indentation. On the other hand, the increase in μ with the large plasticity restricts the piling-up around the frictional indentation, which leads to the decrease in the contact depth. As a result, the increase of indentation loading slope by the increase of the mean pressure is cancelled because of the decrease in the contact depth. The indentation unloading is not significantly affected by the friction for any elastolplasticity of indented solids. Consequently, as far as an indentation on a typical elastoplastic bulk is considered, the friction yields only a small change in apparent nanoindentation behavior.