中国物理B ›› 2003, Vol. 12 ›› Issue (2): 211-217.doi: 10.1088/1009-1963/12/2/317

• CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES • 上一篇    下一篇

Influence of isothermal approximation on the phase-field simulation of directional growth in undercooled melt

于艳梅, 杨根仓, 赵达文, 吕衣礼   

  1. State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an 710072, China
  • 收稿日期:2002-06-28 修回日期:2002-10-14 出版日期:2005-03-16 发布日期:2005-03-16
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No 59971037) and by the Northwestern Polytechnical University Doctoral Dissertation Innovation Foundation, China.

Influence of isothermal approximation on the phase-field simulation of directional growth in undercooled melt

Yu Yan-Mei (于艳梅), Yang Gen-Cang (杨根仓), Zhao Da-Wen (赵达文), Lü Yi-Li (吕衣礼)   

  1. State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an 710072, China
  • Received:2002-06-28 Revised:2002-10-14 Online:2005-03-16 Published:2005-03-16
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No 59971037) and by the Northwestern Polytechnical University Doctoral Dissertation Innovation Foundation, China.

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摘要： By using the phase-field approach, we have simulated the directional growth of alloys in undercooled molten states under the isothermal and nonisothermal conditions. The influences of the isothermal approximation on simulation results are discussed. We found that for undercooling greater than 25K, the isothermal approximation overestimates the interface growth velocity and reduces a critical velocity for an absolute stable planar interface, thus in this simulation, the interface morphology shows the plane-cell-plane transition with increasing initial undercooling of the melt, and the planar interface obtained under a large undercooling is absolutely stable. Whereas in the nonisothermal simulation, only plane-cell transition occurs in the same range of the initial undercoolings of the melt, and the planar interface tends to be destabilized and evolve into cells.

Abstract: By using the phase-field approach, we have simulated the directional growth of alloys in undercooled molten states under the isothermal and nonisothermal conditions. The influences of the isothermal approximation on simulation results are discussed. We found that for undercooling greater than 25K, the isothermal approximation overestimates the interface growth velocity and reduces a critical velocity for an absolute stable planar interface, thus in this simulation, the interface morphology shows the plane-cell-plane transition with increasing initial undercooling of the melt, and the planar interface obtained under a large undercooling is absolutely stable. Whereas in the nonisothermal simulation, only plane-cell transition occurs in the same range of the initial undercoolings of the melt, and the planar interface tends to be destabilized and evolve into cells.

Key words: phase-field, isothermal approximation, directional growth, undercooling

中图分类号:  (Solid-liquid transitions)

  • 64.70.D-
81.40.-z (Treatment of materials and its effects on microstructure, nanostructure, And properties) 68.08.-p (Liquid-solid interfaces)