多晶材料晶粒生长粗化过程的相场方法模拟

Phase field modelling of grain growth in polycrystalline material

基于采用晶体有序化程度参量ψ和晶体学取向θ来表示多晶粒结构的相场模型,利用自适应有限元方法模拟了多晶材料等温过程中的晶粒粗化现象.模拟结果显示,在曲率作用下,通过晶界迁移弯曲晶界逐渐平直化,小晶粒逐渐被大晶粒吞并,当晶界之间的取向差较小时,满足一定能量和几何条件的两晶粒在界面能作用下会发生转动,合并为单个晶粒.模拟结果与实验结果符合较好.因此,该相场模型可以很好地用来模拟固态相变中多晶材料的生长粗化等现象.

Based on the two-parameter phase field model of polycrystalline, the grain growth in polycrystalline material during isothermal holding is simulated by using the adaptive finite element method. The calculated results demonstrates that the cusp grain boundaries are inclined to planar and some small grains coarsen into larger ones through grain boundary migration due to the curvature effect. When the grain boundary misorientations are small enough and meet certain energy and geometric conditions, two grains can rotate to reduce external energy of grain boundaries and coarsen into a single grain. All the modelling results are in good agreement with some experimental observations, and the phase-field model can be successfully employed to simulate polycrystalline grain growth.