2015 Volume 56 Issue 2 Pages 175-181
Thermally activated deformation processes are discussed with reference to the studies done by the present author and his coworkers. First, dislocation motion in one- and two-dimensional periodic stress fields is analyzed to understand the deformation mechanisms of bcc metals and spinodally decomposed alloys. The role of the thermally activated kink-pair formation on the temperature and strain-rate dependence of strength is also discussed. Secondly, diffusion-controlled processes pertinent to high-temperature deformation are discussed by applying a unified and fundamental rate equation derived previously. Thirdly, mechanisms for the temperature and strain-rate dependence of polycrystals and ultrafine-grained and nanocrystalline materials are introduced. A proposed model taking into account the thermally activated dislocation depinning at grain boundaries is discussed.