Determination of creep parameters from indentation creep experiments: a parametric finite element study for single phase materials

This paper explores the possibilities of determining creep parameters for a simple Norton law material from indentation creep testing. Using creep fin ite element analysis the creep indentation test technique is analysed in te rms of indentation rates at constant loads. Emphasis is placed on the evolv ing stress distribution in front of the indenter during indentation creep. Moreover the role of indenter geometry, size effects and of macroscopic con straints is explicitly considered. A simple procedure is proposed to transl ate indentation creep results into constitutive creep equations for cases w here the dimensions of the tested material are significantly larger than th e indenter. The influence of macroscopic constraints becomes important when the size of the indenter is of the same order of magnitude as the size of the testing material. As a striking example for size effects and for macros copic constraints the indentation creep process in a thin film is analyzed. The results contribute to a better mechanical understanding of indentation creep testing.