As an attempt to understand the temperature and strain-rate dependence of strength in nanocrystalline and ultrafine-grained materials, thermally activated de-pinning process was incorporated into a dislocation bow-out model from a grain boundary. Such quantities as activation energy, activation volume, strain-rate sensitivity and yield strength were discussed and compared with experimental results available in literature. It was found that the present model analysis could reasonably explain the observed characteristics of these quantities.

Thermally Activated Dislocation Depinning at a Grain Boundary in Nanocrystalline and Ultrafine-Grained Materials. M.Kato: Materials Science and Engineering A, 2009, 516[1-2], 276-82