Curvature-Driven Grain Growth By Cellular Automaton Simulation In Isothermal Process

Grain growth is a main phenonmenon in annealling process.The average grain size is an importrant index to measure the properties of materials after annelling, so investigating the grain growth process is of great significance to improve the properties of materials.Grain boundary begin to migrate after recrystallization with the effect og curvature.In this paper, we study the migration rule of triple junction, single grain and polycrystalline aggregate under curvature-driven in isothermal process based on the grain boundary migration theory and Cellular Automaton.The results showed that:(1) The migration rule of triple junction depends on the sides n of grain.Triple junction migrates towards the grain interior and the grain shrinks when n<6; Triple junction migrates towards the grain exterior and the grain grows when n>6.(2) Dihedral or turning angle has important influence on the motion of triple junction. Half a dihedral0value range for (0, p/3] when n<6,the effect that triple junction hinder the system decrease with θ increase;Turning angle0value range for [p/3, p/2) when n<6,the effect that triple junction hinder the system enhance with0increase.(3) The deformation rule of single grain depends on the the sides n of grain. The grain shrinks when n<6; grain grows when n>6; stay still when n=6.To summarize,the grain boundary migrate towards the centre of curvature under curvature-driven.(4) In polycrystalline aggregate, the grain boundary will migrate towards the centre of curvature under curvature-driven because the grain boundary is not straightness until the grain boundary achieve a stable state.