Evaluating plastic flow properties by characterizing indentation size effect using a sharp indenter

Abstract

The strain-hardening exponent, used in describing the plastic flow properties of materials, is evaluated from the characteristic length in the indentation size effect (ISE). A linear relationship is found between the strain-hardening exponent and the log of the ISE characteristic length for Ni and SCM21 (structural steel) samples with different plastic pre-strain values. These results are explained through the Taylor dislocation hardening model and a representative stress-strain approach. A dimensionless function characterizing the plastic deformation using only parameters generally measurable by nanoindentation testing is also proposed. The feasibility of developing a unique dimensionless function is studied for 22 metals.