On the elastic effects in power-law indentation creep with sharp conical indenters

The elastic deformation contribution can significantly affect the measurement of the strain-rate sensitivity (SRS) of the plastic flow stress by indentation methods. In this paper, the effect of such elastic contribution is critically analyzed using an extension of a previous treatment developed by the authors for the elastic effects on the indentation of strain-hardening materials [J. Alkorta et al., J. Mater. Res.20, 432 (2005)]. The analytical model is calibrated and validated through finite element calculations. The results show that when the elastic contribution to the total deformation is not negligible then the measured SRS is significantly lower than the real one. A satisfactory correction factor for the apparent SRS exponent is proposed based on parameters directly accessible to instrumented indentation test results.