Simulation of the Dendritic Growth Velocity for Binary Alloy Al-Cu in the Undercooled System

Abstract

The phase-field model was applied to simulate the solidification kinetics to undercooled Al-Cu alloy. The relationships between material properties and model parameters are presented. The diffusivity of solute in the solid region and liquid and liquidus temperature are calculated during the simulation of solidification process. As an example, the two-dimensional computations for the dendritic growth in Al-Cu binary alloy have been performed. The dendritic morphology calculated by phase-field model showed features that are commonly found in experiments on the solidification. The concentration profiles of solute calculated in the solid region and liquid are not completely horizontal, showing evidence of microsegregation. The velocity of the dendrite tip and solute concentration at the interface front are calculated. It is found that the tip velocity is greatly concentration dependent around interface. In order to validate the growth kinetics predicted by this model tests have been performed for comparison with Stefanescu's model. The present work based results show good agreement with those obtained by Stefanescu. The dependence of growth velocity on the initial concentration and super-cooling are also demonstrated.