强界面能各向异性下二元Ni-Cu合金枝晶生长过程的相场法模拟

基于Wheeler模型和Eggleston修正强界面能各向异性的方法,建立耦合溶质场和温度场的相场模型,模拟强界面能各向异性下Ni-Cu合金枝晶生长过程.结果表明:在强界面能各向异性作用下,界面方向枝晶生长不连续且枝晶出现棱角；由于枝晶尖端温度梯度和溶质梯度较大,枝晶生长迅速.当界面能各向异性强度低于临界值时,枝晶尖端生长速度随界面能各向异性强度的增加而增大；当界面能各向异性强度等于临界值时,枝晶尖端生长速度下降4.34％；当界面能各向异性强度大于临界值时,枝晶尖端生长速度随界面能各向异性强度的增加先增大到极大值后逐渐减小.当无量纲热过冷度较小时,晶体平衡形貌为类矩形；随着无量纲热过冷度的增加,晶体平衡形貌向枝晶转变,枝晶尖端生长速度先呈幂指数增加,然后呈线性增加,枝晶生长由扩散控制转变为动力学控制.

Phase-field simulation of dendrite growth process for binary Ni-Cu alloy with anisotropy of strong interface energy

Based on the Wheeler model and the Eggleston regularization technique of the anisotropy of strong interface energy,the phase-field model was built by coupling the solute field with temperature field,and the dendrite growth process of the anisotropy of strong interface energy of Ni-Cu alloy was simulated.The results show that the variation of interface orientation discontinuous and the corners form on the dendrite with the anisotropy of strong interface energy,the dendrites grow fast due to the large tempera...