• CN: 11-2187/TH
  • ISSN: 0577-6686

Journal of Mechanical Engineering ›› 2018, Vol. 54 ›› Issue (2): 62-69.doi: 10.3901/JME.2018.02.062

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Influence of the Crystal Orientation of Epitaxial Solidification on the Linear Instability Dynamic during the Solidification of Welding Pool

ZHENG Wenjian1, HE Yanming1, YANG Jianguo1,2, DONG Zhibo2   

  1. 1. Institute of Process Equipment and Control Engineering, Zhejiang University of Technology, Hangzhou 310014;
    2. State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001
  • Received:2017-08-25 Revised:2017-12-04 Online:2018-01-20 Published:2018-01-20

Abstract: To study the influence of the crystal orientation of epitaxial solidification on the linear instability dynamic, coupled equations are conducted to present the transient conditions of crystal growth near the fusion line of the welding pool. A quantitative phase field model is used to simulate the epitaxial solidification with different crystal orientations. Moreover, a linear instability dynamic analytical model is presented to describe the variation of the onset of the initial planar instability with surface tension anisotropy. The initial average wavelengths obtained by the phase field model and the analytical model are in good agreement with that in experiment result. The epitaxial solidification results show that the greater the angle between the crystal orientation and the temperature gradient, the better the stability of the interface, and the larger the critical time of onset of initial planar instability. Due to the transient of the growth conditions in welding pool and the randomness of the amplification mechanism, it could not show up the law that the greater the crystal orientation angle, the larger the initial average wavelength. Thus, the initial average wavelength of planar instability is seemly independent of the crystal orientation of epitaxial solidification.

Key words: crystal orientation, epitaxial solidification, linear instability, phase field, solidification of welding pool

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