Phase field modeling the selection mechanism of primary dendritic spacing in directional solidification
Phase field modeling the selection mechanism of primary dendritic spacing in directional solidification
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DOI：
10.1016/j.actamat.2011.12.029
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发表时间：
2012-03
期刊：
影响因子：
9.4
通讯作者：
Zhijun Wang;Junjie Li;Jincheng Wang;Yaohe Zhou
中科院分区：
文献类型：
--
作者：
Zhijun Wang;Junjie Li;Jincheng Wang;Yaohe Zhou
采用相场法研究了定向凝固中一次枝晶间距的选择机制。结果表明，初级间距的下限和上限分别由枝晶间溶质相互作用和枝晶间过冷度决定。由于第三臂过度生长而导致的初级间距的上限可能是下限的大约四倍。恒定拉速定向凝固过程中从平面失稳开始的微观结构演化可分为三个阶段：初始竞争阶段、浸没阶段和横向调整阶段。模拟结果还表明，由于枝晶浸没机制，恒定拉速下的最终初级间距非常接近下限。
Selection mechanisms of primary dendritic spacing in directional solidification are investigated by the phase field method. Results show that the lower and upper limits of primary spacing are determined by the interdendritic solutal interactions and the interdendritic undercooling respectively. The upper limit of primary spacing resulting from overgrowth of the tertiary arm could be about four times as large as the lower limit. The microstructural evolution from the onset of planar instability during directional solidification with a constant pulling velocity can be divided into three stages: an initial competition stage, a submerging stage and a lateral adjustment stage. Simulation results also demonstrate that the final primary spacing with a constant pulling velocity is very close to the lower limit due to the dendrite submerging mechanism.