Si-Ni合金中小晶面枝晶生长的相场法模拟

Phase-field method simulation of faceted dendrite growth in Si-Ni alloy

相场法作为一种有效预测过冷熔体凝固过程的数值模拟计算方法,在模拟枝晶生长方面得到了广泛应用。应用界面能的校正形式,建立二元合金小晶面枝晶生长的相场模型,对Si-Ni二元合金小晶面枝晶生长进行了模拟。结果表明,当各向异性强度系数超过临界值υ=1/15时,枝晶生长表现出小晶面生长形态,尖端曲率效应消失,呈现出棱角状的不连续结构;同时在枝晶主支上产生大量侧向分支。实验观察验证了小晶面枝晶生长相场模型的有效性。

As a useful numerical modeling method in predicting solidification process of supercooled melt,phase-field method was applied in simulating the dendrite growth extensively.In this paper,a phase-field model of faceted dendrite growth in binary alloy was built by adj usting interface energy,and the faceted dendritic growth of Si-Ni binary alloy was simulated.The simulation results showed that,when the anisotropic strength coeffi-cientυexceeded the critical value 1/1 5 ,the morphology of dendritic growth performed as a faceted dendrite, and the curvature effect disappeared,then a discontinuous angular contracture was presented;and a large num-ber of side-branches generated in the spine of the primary dendrite.The availability of the faceted dendritic phase-field model was verified by experimental observation.