Fe-C二元合金凝固过程枝晶偏析的数值模拟研究  

Numerical Simulation of Dendritic Segregation in the Fe-C Binary Alloy Solidification Process

作　　者：李继红[1] 汪强[1] 吴伟刚[1] 张敏[1] 

机构地区：[1]西安理工大学材料科学与工程学院,西安710048

出　　处：《材料导报》2013年第12期152-155,共4页Materials Reports

基　　金：国家自然科学基金(51274162);陕西省自然科学基金(2012JM6003);西安市科技计划(CX1250②)

摘　　要：利用元胞自动机法对Fe-C二元合金过冷熔体中枝晶的生长过程进行了模拟,其中明确地将液相溶质浓度与固相溶质浓度区分开,并探讨了冷却速率、液相溶质扩散系数以及固相溶质扩散系数对枝晶偏析的影响规律。模拟结果表明:随着冷却速率的增大,固相中溶质浓度波动不断加剧,且枝晶偏析程度增大,但偏析程度的增大趋势逐渐减缓;当液相扩散系数变化时,液相溶质扩散系数越小,其微观偏析越严重,此外,固相中溶质的波动随液相扩散系数的增大而减小;当固相溶质扩散系数变化时,在枝晶中心附近,微观偏析程度基本保持一致,而在远离中心点的外围区域,微观偏析程度的波动十分明显。Equiaxed crystal growth process of the Fe-C binary alloy in the undercooled melt was simulated by the method of cellular automata. In the simulation, liquid solute concentration and solid solute concentration were distinguished definitely. Moreover, the influence of dendritic segregation under the different cooling rates, the different liquid phase diffusion coefficient and the different solid-phase diffusion coefficient were discussed. The results show that, when the cooling rate increases, fluctuations of the solid-phase solute are intensified, the degree of dendrite seg- regation is increased, but the increasing trend is decreased. When the liquid phase diffusion coefficient changes, the smaller the liquid solute diffusion coefficient is, the more serious dendritic segregation is. At the same time, fluctua- tions in the solid phase solute decreases with the increasing of liquid phase diffusion coefficient. When the solid phase solute diffusion coefficient changes, the degree of dendritic segregation is basically the same near the center of equiaxed grains, but away from the center point, fluctuations of the degree is very obvious.

关 键 词：元胞自动机 枝晶偏析 数值模拟 冷却速率 溶质扩散系数 

分 类 号：TG111.4[金属学及工艺—物理冶金]