A molecular dynamics simulation study was made of the migration of grain boundaries with triple junctions. The grain-boundary profile, triple-junction angles and rate of grain-boundary migration were monitored as a function of grain size, grain misorientation, direction of migration and temperature; using configurations which were designed to

ensure steady-state migration. The results demonstrated that triple-junction mobility was finite and could be sufficiently small to limit the rate of grain-boundary migration. The drag on grain boundaries, due to limited triple-junction mobility, was important at small grain sizes, low temperature and near to high-symmetry grain misorientations. This drag limited the rate of grain-boundary migration, and led to triple-junction angles that differed markedly from their equilibrium values. Simulation data suggested that triple-junction drag was much more relevant at low temperatures than at high temperatures. The triple-junction mobility was shown to depend upon the direction of triple-junction migration. The results were in excellent qualitative agreement with experimental observations.

Molecular Dynamics Simulation of Triple Junction Migration. M.Upmanyu, D.J.Srolovitz, L.S.Shvindlerman, G.Gottstein: Acta Materialia, 2002, 50[6], 1405-20