The role of intrinsic material length scales in micro-indentation simulations

It is known that the hardness from nano- and micro-indentation tests characterizes mechanical property of materials at micro-level and depends significantly on the indentation depth. The depth-dependent micro-hardness can be modelled using gradient plasticity models. In the present paper the role of the intrinsic material length parameters in the gradient plasticity models is systematically studied. Two different flow stress formulations are adopted and effects of the intrinsic material length scales are quantitatively discussed. Comparison with the known experiments confirms that the computational predictions in the gradient plasticity can catch the size effects in micro-indentation tests accurately.