Phase-Field Crystal Study Of Topological Evolution During Grain Annihilation Process In Polycrystalline Materials

The topological evolution and annihilation mechanism of the three-, four- and five-sided grains are studied by using the phase field crystal (PFC) model. Both the large-angle and small-angle grain boundaries are discussed during the grain annihilation process. The results show that for the large-angle grain boundaries, grain annihilation is achieved through grain boundaries migration and absorption by triple junction. For the small-angle grain boundaries, the grain annihilation is achieved by dislocation slip, reaction, and absorption by triple junction. However, when the number of sides of a grain increases to seven, the grains show obvious growth instead of annihilation. Two kinds of growth mechanisms for the seven-sided grain are obtained by simulating the growth process. The effects of the number of grain sides on the evolution of grain annihilation are explored. These results are consistent with the Von Neumann-Mullins model and Euler formula.