Modeling grain growth behavior inhibited by dispersed particles

Grain growth behavior in particle-dispersed materials is investigated by mo deling the interaction between grain boundaries and particles. The elementa ry interaction between a grain boundary with single curvature and a particl e is simulated using the axisymmetric finite element method. Three-dimensio nal distribution of particles is characterized by the equivalent interparti cle distance, and the restraining pressure of the particles is evaluated by considering the velocity effect of the boundary migration. The evaluated r estraining pressure increases with increasing radius of the boundary curvat ure and the increasing rate is accelerated as the critical radius is approa ched. The predicted critical grain size is proportional to f(-0.9) for f ap proximate to0.01 and f(-0.7) for f approximate to0.1, where f is the volume fraction of particles. The experimental comparison of the critical grain s ize shows good consistency. The power law for grain growth is found to be r etained even in particle-dispersed materials for f<0.25, while the grain gr owth exponent varies with 2 + 1.76f(0.5). Zener's model is also modified by considering the velocity effect of the boundary migration and compared wit h the present model. (C) 2001 Acta Materialia Inc. Published by Elsevier Sc ience Ltd All rights reserved.