Existence or nonexistence of thermal pinning effect in grain growth under temperature gradient

In order to clarify existence or nonexistence of the thermal pinning, viz., retardation of grain growth in polycrystalline materials due to steep temperature gradient, effects of the temperature gradient on the grain growth were systematically investigated by means of the phase-field simulations. It was found that the local grain growth is determined only by the local thermal history regardless of the temperature gradient, and hence, the temperature gradient does not directly influence the local grain growth. It was concluded that the thermal pinning does not exist when the grain boundary energy and mobility are isotropic, and the grain growth is driven only by the reduction of total grain boundary energy.