中国物理B ›› 2008, Vol. 17 ›› Issue (9): 3516-3522.doi: 10.1088/1674-1056/17/9/063

• 8000 CROSSDISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY • 上一篇    下一篇

Phase field simulation of the columnar dendritic growth and microsegregation in a binary alloy

李俊杰, 王锦程, 杨根仓   

  1. State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an 710072, China
  • 收稿日期:2008-01-23 修回日期:2008-02-24 出版日期:2008-09-08 发布日期:2008-09-08
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No 50401013) and Doctorate Foundation of Northwestern Polytechnical University, China.

Phase field simulation of the columnar dendritic growth and microsegregation in a binary alloy

Li Jun-Jie(李俊杰), Wang Jin-Cheng(王锦程)†, and Yang Gen-Cang(杨根仓)   

  1. State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an 710072, China
  • Received:2008-01-23 Revised:2008-02-24 Online:2008-09-08 Published:2008-09-08
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No 50401013) and Doctorate Foundation of Northwestern Polytechnical University, China.

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摘要： This paper applies a phase field model for polycrystalline solidification in binary alloys to simulate the formation and growth of the columnar dendritic array under the isothermal and constant cooling conditions. The solidification process and microsegregation in the mushy zone are analysed in detail. It is shown that under the isothermal condition solidification will stop after the formation of the mushy zone, but dendritic coarsening will progress continuously, which results in the decrease of the total interface area. Under the constant cooling condition the mushy zone will solidify and coarsen simultaneously. For the constant cooling solidification, microsegregation predicted by a modified Brody-Flemings model is compared with the simulation results. It is found that the Fourier number which characterizes microsegregation is different for regions with different microstructures. Dendritic coarsening and the larger area of interface should account for the enhanced Fourier number in the region with well developed second dendritic arms.

Abstract: This paper applies a phase field model for polycrystalline solidification in binary alloys to simulate the formation and growth of the columnar dendritic array under the isothermal and constant cooling conditions. The solidification process and microsegregation in the mushy zone are analysed in detail. It is shown that under the isothermal condition solidification will stop after the formation of the mushy zone, but dendritic coarsening will progress continuously, which results in the decrease of the total interface area. Under the constant cooling condition the mushy zone will solidify and coarsen simultaneously. For the constant cooling solidification, microsegregation predicted by a modified Brody-Flemings model is compared with the simulation results. It is found that the Fourier number which characterizes microsegregation is different for regions with different microstructures. Dendritic coarsening and the larger area of interface should account for the enhanced Fourier number in the region with well developed second dendritic arms.

Key words: phase field model, solidification, columnar dendrite, microsegregation

中图分类号:  (Whiskers and dendrites (growth, structure, and nonelectronic properties))

  • 68.70.+w
64.70.D- (Solid-liquid transitions) 64.75.-g (Phase equilibria) 81.30.Fb (Solidification)