Kinetics of diffusional creep discussed by energy dissipation and effect of grain-size distribution on the rate equations

Abstract The kinetics of diffusional creep of polycrystals is examined using an energy balance method. In the steady state of diffusional creep, work done by an applied stress is considered to be dissipated as heat by sliding of grain boundaries and diffusion of atoms. Describing the sliding and diffusion as Somigliana's dislocations on grain boundaries, the rate equations for Coble creep and Nabarro–Herring creep are derived by using this energy balance. The energy consideration adopted in the present study is simple and enables us to grasp the physics of diffusional creep. Using the energy consideration, we also discuss the effects of grain-size distribution in polycrystals on the rate equations, which have not been treated in previous studies.