The impact of stochastic atomic jumps on the kinetics of curvature-driven grain growth

A model for grain growth allowing stochastic jumps of atoms across boundaries to occur concurrently with curvature-driven boundary migration has been solved numerically. At small grain sizes, the stochastic mechanism controls the overall rate of grain growth, whereas at large sizes, the growth rate is governed by the boundary curvature. The transition between the two regimes occurs smoothly over a range of grain sizes about one order of magnitude in width. Since the upper bound of the transition range is estimated to lie below 20 nm for most polycrystalline materials, the stochastic mechanism is expected to be relevant to the measurement and modeling of grain growth only in nanocrystalline samples. (C) 2003 Acta Materialia Inc. Published by Elsevier Science Ltd. All rights reserved.