J. Mater. Sci. Technol. ›› 2019, Vol. 35 ›› Issue (6): 1044-1052.DOI: 10.1016/j.jmst.2018.12.009

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Phase-field simulation for the evolution of solid/liquid interface front in directional solidification process

Yuhong Zhaoa*(), Bing Zhanga, Hua Houa*(), Weipeng Chena, Meng Wangb   

  1. a College of Materials Science and Engineering, North University of China, Taiyuan 030051, China
    b State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xian 710072, China
  • Received:2018-07-13 Revised:2018-08-24 Accepted:2018-08-26 Online:2019-06-20 Published:2019-06-19
  • Contact: Zhao Yuhong,Hou Hua
  • About author:

    1The authors contributed equally to this work.

Abstract:

In this study, the phase field method was used to study the multi-controlling factors of dendrite growth in directional solidification. The effects of temperature gradient, propelling velocity, thermal disturbance and growth orientation angle on the growth morphology of the dendritic growth in the solid/liquid interface were discussed. It is found that the redistribution of solute leads to multilevel cavity and multilevel fusion to form multistage solute segregation, and the increase of temperature gradient and propelling velocity can accelerate the dendrite growth of directional solidification, and also make the second dendrites more developed, which reduces the primary distance and the solute segregation. When the temperature gradient is large, the solid-liquid interface will move forward in a flat interface mode, and the thermal disturbance does not affect the steady state behavior of the directionally solidified dendrite tip. It only promotes the generation and growth of the second dendrites and forms the asymmetric dendrite. Meanwhile, it is found that the inclined dendrite is at a disadvantage in the competitive growth compared to the normal dendrite, and generally it will disappear. When the inclination angle is large, the initial primary dendrite may be eliminated by its secondary or third dendrite.

Key words: Phase field method, Directional solidification, Interface morphology, Multi-control factors