关键词: 起伏, 树枝晶, 相场方法

Abstract: The growth process of side-branching of dendrites during solidification of pure Ni melt was studied by the phasefield simulation. The phasefield model was modified by coupling both structural fluctuation and energetic fluctuation. The simulation results indicate that with an increase of undercooling, the velocity and radius of the dendritic tip increases, and the sidebranch becomes intense. It is also found that as the level of the structural fluctuation and energetic fluctuation is increased the side-branch become richer, and a morphological transition takes place with dendrite tipsplitting (doubloon formation) resulting in the normal dendrite morphology being replaced by the dendritic‘seaweed’ morphology.

Key words: dendrite, phase field method , fluctuations