中国物理B ›› 2005, Vol. 14 ›› Issue (4): 838-843.doi: 10.1088/1009-1963/14/4/036

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Modelling the crystal growth in highly undercooled alloy melts by non-isothermal phase-field method

李梅娥1, 杨根仓2, 周尧和2   

  1. (1)School of Material Science and Engineering, Xi'an Jiaotong University,Xi'an,710049, China; (2)State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an, 710072, China
  • 收稿日期:2004-07-23 修回日期:2004-10-02 出版日期:2005-04-20 发布日期:2005-03-28
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos 50395103 and 50271057) and by the fund of the State Key Laboratory of Solidification Processing in NPU, China.

Modelling the crystal growth in highly undercooled alloy melts by non-isothermal phase-field method

Li Mei-E (李梅娥)a, Yang Gen-Cang (杨根仓)b, Zhou Yao-He (周尧和)b   

  1. a School of Material Science and Engineering, Xi'an Jiaotong University,Xi'an 710049, China; b State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an 710072, China
  • Received:2004-07-23 Revised:2004-10-02 Online:2005-04-20 Published:2005-03-28
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos 50395103 and 50271057) and by the fund of the State Key Laboratory of Solidification Processing in NPU, China.

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摘要： A non-isothermal phase-field model is used to simulate the rapid solidification of highly undercooled alloy melts. The influence of undercooling on the solidification process is studied. It is indicated that with the increase of undercooling, the dendrite morphology changes from poorly developed dendrite, via the well-developed dendrite containing secondary and ternary arms, to the compact diamond-shaped grain. With increasing undercooling, the tip radius changes in the following rule: decrease $\to$ increase $\to$ decrease while the growth velocity increases constantly,which is consistent with the results predicted by the Boettinger--Coriell--Trivedi model. The thermal, solutal and kinetic undercooling contributions under different initial undercooling are also determined. It is shown that when the undercooling is increased beyond a certain value, the thermal undercooling contribution exceeds the solutal contribution and the dendrite growth transits from solutal diffusion controlled to thermal diffusion controlled one.

关键词: high undercooling, non-isothermal phase-field method, dendrite morphology, operating state of dendrite tip

Abstract: A non-isothermal phase-field model is used to simulate the rapid solidification of highly undercooled alloy melts. The influence of undercooling on the solidification process is studied. It is indicated that with the increase of undercooling, the dendrite morphology changes from poorly developed dendrite, via the well-developed dendrite containing secondary and ternary arms, to the compact diamond-shaped grain. With increasing undercooling, the tip radius changes in the following rule: decrease $\to$ increase $\to$ decrease while the growth velocity increases constantly,which is consistent with the results predicted by the Boettinger--Coriell--Trivedi model. The thermal, solutal and kinetic undercooling contributions under different initial undercooling are also determined. It is shown that when the undercooling is increased beyond a certain value, the thermal undercooling contribution exceeds the solutal contribution and the dendrite growth transits from solutal diffusion controlled to thermal diffusion controlled one.

Key words: high undercooling, non-isothermal phase-field method, dendrite morphology, operating state of dendrite tip

中图分类号:  (Growth from melts; zone melting and refining)

  • 81.10.Fq
81.10.Aj (Theory and models of crystal growth; physics and chemistry of crystal growth, crystal morphology, and orientation) 64.70.D- (Solid-liquid transitions) 68.70.+w (Whiskers and dendrites (growth, structure, and nonelectronic properties))