Investigation into the nanoindentation size effect using static atomistic simulations

Strain gradient theory predicts that the increase in hardness of a material is inversely proportional to the square root of the indentation depth for indentation in the micrometer regime. The aim of this study is to investigate the validity of this phenomenon in the nanometer regime. The simulation results indicate that nanohardness does not have a strong depth dependence in the nanometer regime. However, if the Oliver-Pharr scheme is applied for the measurement of the contact area, a prominent size effect is nevertheless observed. Therefore, this study also investigates the inability of the Oliver-Pharr scheme in the nanometer regime. (c) 2006 American Institute of Physics.