Zhu Changsheng  Wang Zhiping

(CAD Center, Lanzhou University of Technology, Lanzhou 730050)

Liu Baicheng  Jing Tao

(Department of Mechanical Engineering, Tsinghua University, Beijing 100084)

Abstract: The dependence dendritic sidebranching on phase- field parameters is studied by using a phase-field model which incorporates thermal noise quantitatively. The calculated results indicate that, with the increment of undercooling, the thermal diffusion layer collected around the equiaxed dendritic is more thin, which is advantageous to the growth of the sidebranching and the equiaxed dendritic presents the morphology of developed sidebranching; The anisotropy parameter e influence the steady state of the dendrite tip, the larger e, the quicker the dendrite tip velocity is, the more developed the side-branches are and the smaller the DAS are; The smaller coupling coefficient l, the quicker the dendrite tip velocity converges on the Green function calculation, the more developed the side-branches are; The magnitude of thermal noise influence temperature field obviously, when appropriate value is assigned to Fu, noise can enhance the emergence of sidebranching but does not influence the tip operating state.

Key words: Phase-field Method   Thermal noise  Undercooling   Sidebranching  Numerical simulation

CLC No: TG248  TG244

国家自然科学基金资助项目(50005011, 59990490). Received 20040811, received in revised form 20041122