Evaluating local strain rate sensitivity of titanium alloy using dynamic nanoindentation testing

Constant strain rate nanoindentation testing is useful for evaluating local strain rate sensitivity. In titanium alloys, the dwell fatigue at room temperature is a critical issue, and this phenomenon is known as relating to local strain rate sensitivity. We investigate the local strain rate sensitivity of Ti–6242S and IMI834 which are well known heat resistant titanium alloys. Firstly, the validity of strain rate sensitivity by using dynamic nanoindentation testing was verified by measuring the material which has low strain rate sensitivity. Then, rate sensitivity of titanium alloy was examined by nanoindentation testing. Combined with the results from the structural analysis by the electron back scattered diffraction pattern, the factors which affect the strain rate sensitivity are investigated