Determining the activation energy and volume for the onset of plasticity during nanoindentation

摘要: Nanoindentation experiments are performed on single crystals of platinum, and the elastic-plastic transition is studied statistically as a function temperature indentation rate. The experimental results consistent with thermally activated mechanism incipient plasticity, where higher time-at-temperature under load promotes yield. Using statistical thermal activation model stress-biasing term, data analyzed to extract energy, volume, attempt frequency for rate-limiting event that controls In addition full numerical without significant limiting assumptions, simple graphical approximation also developed quick reasonable estimation parameters. Based these analyses, onset plasticity believed be associated heterogeneous process dislocation nucleation, an atomic-scale, low-energy rate limiter.