Modelling and Simulation of Globular Equiaxed Eutectic Solidification in a Direct Chill Casting of Aluminium Binary Alloy Systems

Abstract

A comprehensive modelling of globular equiaxed eutectic solidification in a direct chill casting of aluminium binary alloy systems has been presented. The modelling applies the finite volume method in a diffusion dominated 2D axisymetric domain. The model couples the macroscopic heat transfer equation with solidification kinetics model to predict total solidification time, actual solidification time, grain size, undercooling, and grain growth rate in the two binary aluminium alloy systems namely; Al-Cu system and Al-Si system. The linearization of the solidification kinetics source term coupled to the heat transfer equation ensures robust and converged computation of the numerical model. The results obtained show that under the same cooling conditions at the billet surface, Al-Cu alloy system solidifies faster than Al-Si alloy system. In addition higher undercooling, grain size and growth rate are evident in the former than the later.