强制对流作用下纯Ni枝晶生长的相场法研究  

Simulation on Dendritic Growth of Pure Ni Using Phase-field Model under Forced Flow

作　　者：袁训锋[1] 丁雨田[2] 

机构地区：[1]商洛学院物理与电子信息工程系,陕西商洛726000 [2]兰州理工大学甘肃省有色金属新材料省部共建国家重点实验室,甘肃兰州730050

出　　处：《铸造技术》2012年第8期913-917,共5页Foundry Technology

基　　金：商洛学院博士启动基金资助项目(12SKY01-1)

摘　　要：基于耦合流场的Wheeler模型,采用有限差分法,对纯镍单枝晶和多枝晶生长过程进行模拟,研究了强制对流对枝晶形貌、温度分布及枝晶臂尖端生长行为的影响。结果表明,在流速为14.76 m/s的垂直强制对流作用下,单枝晶生长时逆流枝晶臂生长迅速,其尖端稳态生长速度比纯扩散时增加了47.14%;顺流枝晶臂生长缓慢,其尖端稳态生长速度比纯扩散时减小了49.72%。模拟结果与Ivanstov理论及试验结果一致。多枝晶生长时,受强制流动、晶体结构特征和生长空间的共同作用,仅有指向逆流侧外部区域的优先生长方向上的枝晶臂生长受到促进,主枝和侧枝发达,其他优先生长方向的枝晶臂生长均受到抑制,主枝和侧枝退化。The phase field model based on Wheeler model coupled with the flow field was used to simulate dendrite growth of single and multi-dendrites of pure Ni by finite difference method. The effect of forced flow on dendrite morphology, temperature distribution and tip growth behavior of pure Ni was studied. The result shows that when the flow velocity is 14.76 m/s, in the case of single-dendrite growth, the upstream arms of dendrite grows fast, the tip velocity at steady state on the upstream is increased by about 47.14% compared with the case without flow. The downstream arms of it grows slow, the tip velocity at steady state on the upstream is decreased by about 49.72% compared with the case without flow. The simulated results are consistent with Ivanstov theory and test result. For multi-dendrites growth, the growth of dendrite arms on the preferred directions toward the out of upstream area is promoted, which make the principal branches and side branches develope. The growth of dendrite arms on the other preferred directions is inhibited, 10rincioal branches and side branches degenerate.

关 键 词：相场法 强制对流 枝晶生长 凝固 

分 类 号：TG131[一般工业技术—材料科学与工程]