Research Center for Advanced Science and Technology, The University of Tokyo, Meguro-ku, Tokyo 153
The dynamics of grain boundary movement is analyzed in two and three dimensions by constructing an atomic jump model. The driving force for the movement is obtained from the decrease of the grain boundary surface energy due to the reduction of the surface area. By considering the diffusion-like atomic jump across the grain boundary, the moving velocity is represented in a form of exp (-1/r), where r is the radius of the curved boundary. The model is applied to the description of the shrinkage behavior of an isolated spherical particle. When r is large, the simulation of the shrinkage behavior gives the nearly same results with the conventional parabolic law of grain growth. The present model also predicts the existence of the critical temperature at which the movement of grain boundary stops. The moving velocity increases with increasing temperature, until it reaches a maximum at a certain temperature and then starts decreasing to zero near the critical temperature.
(Received January 10, 1997)
grain boundary, atomic jump model, driving force, curvature, particle, critical temperature, surface energy
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