Analysis of indentation stress-strain response of copper by in-situ observation using optical indentation microscopy

Abstract

In this study, deformation behavior in a limited region of Cu with various average grain sizes was investigated by optical indentation microscopy (OIM), a novel in-situ indentation method. The relationship between the macroscopic yield stresses estimated from uniaxial compressive tests and the indentation yield stresses in the limited region estimated by OIM followed an empirical model. The yield stresses in the limited region estimated by OIM depend on the grain size, and they satisfied the Hall-Petch relationship as well as the macroscopic yield stress. The macroscopic yield stresses predicted from the indentation yield stresses were consistent with the experimentally estimated values. Therefore, it is concluded that it is possible to estimate the macroscopic yield stress from the deformation behavior of the limited region analyzed by OIM.