Effect of forced lamina flow on microsegregation simulated by phase field method quantitatively

相场法定量模拟强迫层流对微观偏析的影响(英文)

The influence of supercooled melt forced lamina flow on microsegregation was investigated. The concentration distribution at solid-liquid boundary of binary alloy Ni-Cu was simulated using phase field model coupled with flow field. The microsegregation, concentration maximum value, boundary thickness of concentration near upstream dendrite and normal to flow dendrite, and downstream dendrite were studied quantitatively in the case of forced lamia flow. The simulation results show that solute field and flow field interact complexly. Compared with melt without flow, in front of upstream dendrite tip, the concentration boundary thickness is the lowest and the concentration maximum value is the smallest for melt with flow. However, in front of downstream dendrite tip, the results are just the opposite. The zone of poor Cu in upstream dendrite where is the most severely microsegregation and shrinkage cavity is wider and the concentration is lower for melt with flow than that without flow.

采用耦合流场的相场模型,模拟Ni-Cu合金过冷熔体流动对液固界面前沿浓度分布的影响;定量分析强迫层流对迎流方向、垂直流动方向与逆流方向枝晶尖端前沿浓度边界层厚度,浓度最大值和枝晶微观偏析的影响。结果表明:溶质场和流场二者相互影响;枝晶上游侧浓度边界层的厚度较薄,溶质浓度的最大值较小;而枝晶下游侧恰好与此相反。贫Cu区域在迎流方向枝晶臂沿枝晶轴线方向的宽度较大,但Cu原子的浓度较低,微观偏析最严重,枝晶下游侧缩松倾向加剧。