Numerical Modeling of Macrosegregation in Binary Alloys Solidifying in the Presence of Electromagnetic Stirring

A model for predicting solidification and solute segregation of binary alloys undergoing electromagnetic stirring has been developed. A dual-zone formulation was employed to describe the velocity fields in the mushy region. The key feature of this model lies in its accounting for flow damping in the suspended particle region via turbulent interactions the crystallite surfaces. The damping force is given in terms of the turbulent kinetic energy, fraction solid, and the crystallite sphericity. The computed macrosegregation results for Al-4.5 pctCu alloy were validated against, and were found to agree with, experimental measurements. The effect of final grain size and frequency on segregation was also determined. This validated model represents a rigorous mathematical framework for describing the flow behavior and solute segregation in electromagnetically stirred melts.