Simulation of the effect of anisotropic grain boundary mobility and energy on abnormal grain growth

Abnormal grain growth (AGG) can take place when the grain boundaries of a given grain have the growth advantage exclusively over those of the other grains. The growth advantage can be provided either by high mobility or by low energy of the grain boundaries. Monte Carlo simulation is done to determine which of the two factors is more important in inducing AGG. The results of the simulation indicate that the growth advantage by the low energy induces AGG under a more realistic condition if the grain boundary energy is low enough to allow the AGG grain to grow by solid-state wetting. Grain growth by wetting will take place at the triple junction when the sum of the two grain boundary energies is smaller than the other grain boundary energy. Island grains inside the AGG grain are formed both by anisotropic mobility and energy of grain boundaries. High frequency of island grains, however, comparable to that observed in the initial stage of AGG in an Fe-3%Si alloy, is induced under a condition where growth by wetting is favored while the grain boundary migration is suppressed.