相场模拟中金属固-液热扩散系数比对晶体侧向分支形貌的影响

Influence of the Ratio of Solid to Liquid Thermal Diffusivity on Dendrite Side-Branch Morphology Within a Phase-Field Simulation

采用耦合结构起伏和能量起伏的相场方法,系统地研究了纯金属镍的固-液热扩散系数比(μ=ks/kl)对其过冷熔体树枝晶侧向分支形貌的影响规律。研究发现,金属固-液热扩散系数比μ越大,侧向分支的生长受到强烈的抑制,其百分含量减少,同时晶体的RMS距离Zsb越小,晶体的各向异性强度越小。

Dendrite side＇branch growth is studied to examine the effect of the ratio of the thermal diffusivity in the solid .and liquid states （μ=ks/kl） on the side-branching characteristics of the dendrite during the growth of Ni from its undercooled parent melt by simulation of a phase-field model whLch incorporates structural fluctuation and energetic fluctuation of microscopic origin. The calculated results indicate as the ratio is increased the side-branch become strongly Suppressed and meanwhile, the RMS distance at which the mean amplitude of the side-branches is equal to the tip radius becomes little and anisotropy becomes weak.