Simulation of the influence of particles on grain structure evolution in two-dimensional systems and thin films

A two-dimensional front-tracking simulation of grain growth has been extended to treat the effects of particles on the evolution of grain structures during annealing. When grain boundaries come into contact with particles, boundary motion is assumed to be pinned. It is found that even a small volume fraction of particles retards grain growth, lowers the ultimate average grain size, and leads to significant changes in the grain-size and number-of-sides distributions. These changes differ in detail from the changes in the grain-size distribution predicted using the Potts model. The changes in the nature of the grain-size distribution are explained by considering the topology of the evolving and of the stagnant grain structures. The average grain size in the stagnant structure scales with the number of particles in a way consistent with a scaling with area fraction of the particles to the power 0.46, in near agreement with the expected dependence from a Zener-pinning analysis in two dimensions. Particle pinning is also simulated in conjunction with the effects of other mechanisms impeding grain growth such as solute drag or grain boundary grooving. In this case it is found that the stagnant grain-size distribution is determined by the competing stagnation forces, and that the Zener-pinning analysis is not obeyed and must be modified. (C) 1999 Acta Metallurgica Inc. Published by Elsevier Science Ltd. All rights reserved.