外来夹杂物颗粒对枝晶生长形态影响的相场法研究

在KKS相场模型基础上提出了一种耦合取向场的二元合金相场模型.通过该模型分析了外来夹杂物颗粒与晶粒之间的取向错配对于枝晶生长的影响，模拟结果表明外来夹杂物颗粒的大小、位置、数量以及与晶粒的取向差等因素均对枝晶生长形态有较大影响，外来夹杂物颗粒会造成枝晶臂的偏转与分叉，从而最终形成各种形貌的非规则枝晶. 关键词： 相场法 枝晶 外来夹杂物颗粒 晶体取向

Effect of foreign particles on the dendritic growth in phase-field theory

The presence of foreign particles in the undercooled melt can influence the evolution of solidification structure and change the dendritic morphology.In this work,according to the KKS model,a hybrid phase field model for binary alloys,which takes into account the random crystallographic orientation,is developed to analyze the effect of misorientation between foreign particles and crystal grains on the dendritic growth.The simulation results show that the influence of foreign particles depends on the particle size,position,numbers and the degree of misorientation.The foreign particles which do not match the initial orientation of the crystal cause the dendrite trunks to deflect and split,leading to the formation of irregular dendritic morphology.