摘要
基于KKS模型,采用耦合相场和溶质场的方法,对Fe-0.5mol%C合金凝固过程中的枝晶生长进行了模拟,并研究了过冷度、各向异性强度和扰动强度对枝晶生长形貌的影响。结果表明:随着过冷度的减小,枝晶主干细化,各向异性程度增大,晶粒生长速度减小,溶质扩散层厚度增加,枝晶的最高溶质浓度降低,溶质梯度减小;随着各向异性的增加,晶粒由海藻状转变为枝晶态,枝晶生长速度也随之增大;扰动强度引发了侧向分枝,侧枝间互相竞争生长,根部出现"颈缩"现象,但扰动强度的加入并不改变枝晶尖端的稳态行为。
The phase-field model based on KKS model which is coupled with solute-field has been used to simulate the microstructural dendrite growth of Alloy Fe-C0. 5mol%. The influence of undercooling, anisotropic intensity and noise intensity on dendrite growth has been investigated. The results show that with decreasing of undercooling, the morphology of dendritic trunk will become thinner, while anisotropic degree is increased, the speed of dendrite growth is decreased, thickness of solute diffusion layer is increased. The maximum solute concentration is decreased, the solute gradient is decreased. With increasing of anisotropic intensity,the grain morphology is transformed from seaweed to dendrite, and the speed of dendrite growth is increased. The noise intensity will introduce the growth of side-branches. There are some phenomena just as the side-branches competitive growth and the necking of the dendrite root. The noise intensity cannot change the steady-state behavior of dendrite tip.
出处
《铸造技术》
CAS
北大核心
2008年第2期244-249,共6页
Foundry Technology
基金
陕西省教育厅科研专项(06JK276)
教育部优秀青年教师奖励计划资助项目
关键词
等温凝固
相场法
微观组织
数值模拟
Isothermal solidification
Phase-field method
Microstructure
Numerical simulation
