An atomistic study of the correlation between the migration of planar and curved grain boundaries

Molecular dynamics simulations were performed to investigate the migration of curved and planar boundaries. The reduced mobilities of capillarity driven U-shaped half-loop twin boundaries in b.c.c iron (Fe) were computed between 800 and 1200 K. To rationalize these results, simulations were also performed for planar twin boundaries of different inclination to determine their absolute mobilities and grain boundary energies. The variation of these properties with inclination was integrated into a continuum model which was found to produce the steady-state shapes of curved boundaries consistent with those from simulations. A further extension of the continuum model enabled estimations of the reduced mobility that were in good agreement with simulation results. It was also identified that atomistic events governing the migration of curved and planar boundaries shared a number of similarities. Overall, the analyses of the shapes, mobilities and atomic-scale migration mechanisms of curved and planar boundaries presented here provide a correlation between the migration of these types of twin boundaries. Crown Copyright (C) 2016 Published by Elsevier B.V. All rights reserved.