On the transitions among different creep regimes

The conditions marking the transitions among Harper–Dorn (H–D), grain boundary sliding (GBS) and power-law creep are studied. This is based on our recently developed models for these three kinds of creep. It is shown that the theoretically predicted transition conditions are in good agreement with experimental data, and Peierls stress is an important factor in controlling the transitions. A deformation mechanism map is constructed with the incorporation of Peierls stress. It is illustrated that H–D creep may be a dominant mechanism in materials with high Peierls stress over wide ranges of grain size and stress.