The roles of grain-boundary sliding and dislocation-pope diffusion in high-strain-rate superplasticity

摘要

Much attention has been given recently to superplastic behavior at high strain rates in materials with extremely fine grain sizes. A viable theory is available to explain high-strain-rate superplasticity in such materials at high homologous temperature, where incipient melting can occur at grain boundaries. For the case of very-fine-grained materials deformed at temperatures where incipient melting is unlikely a different explanations is needed. A theory based on the assistance of dislocation-pip diffusion to the grain-boundary sliding process is presented.