过冷度影响Fe-C合金枝晶生长的相场研究  

Study of Undercooling Influencing Dendrite Growth of Fe-C Alloy Using Phase Field Method

作　　者：袁训锋[1] 杨燕[1] 李春[1] 刘宝盈[1] 丁雨田[2] 

机构地区：[1]商洛学院,陕西商洛726000 [2]兰州理工大学,甘肃兰州730050

出　　处：《中国铸造装备与技术》2013年第6期15-19,共5页China Foundry Machinery & Technology

基　　金：商洛学院博士启动基金资助项目(12SKY01-1)

摘　　要：采用耦合流场的相场模型,模拟了强制流动作用下Fe-C合金等温凝固中的枝晶生长过程,研究了过冷度对枝晶生长行为的影响。结果表明:在纯扩散条件下,枝晶臂尖端为抛物线形,主枝根部有明显的二次分支。在强制流动作用下,逆流侧区域枝晶臂受过冷熔体冲刷,侧枝生长受到促进,形成发达二次枝晶;顺流侧区域富集大量溶质,不利于侧枝的形成和生长,无二次分支出现。随着过冷度的增加,逆流尖端生长速度和溶质摩尔分数均线性增加;顺流尖端生长速度二次函数增加,但顺流尖端的溶质摩尔分数先减小后增加。The phase field model within coupling flow field has been used to simulate the dendrite growth process under forced flow during isothermal solidification of Fe-C alloy with research on effects of undercooling on the dendrite growth. The results have shown that the tip of dendrite arm was in shape of parabola and the secondary branches appeared at the root of main branches under the pure diffusion conditions. Under forced flow the undercooled melt flushing the dendrite arms in upstream side, which was advantageous to the growth of the side dendrite, the side-branches became developed secondary dendrites. The solute enriched in the downstream side, which was disadvantageous to the formation and growth of the side-branches, no secondary branches appeared on principal branch. With the increasing of undercooling, both the tip velocity and solute mole fraction of upstream dendrite increased linearly. And the growth velocity of tip of downstream dendrite increased in accordance with quadratic functional form but tip solute mole fraction decreased at first and then increased.

关 键 词：FE-C合金 相场法 强制流动 枝晶生长 过冷度 

分 类 号：TG111[金属学及工艺—物理冶金]