A phase field model coupled with pressure-effect-embedded thermodynamic modeling for describing microstructure and microsegregation in pressurized solidification of a ternary magnesium alloy

This paper presents a phase field model for describing microstructure and microsegregation in pressurized solidification of a ternary magnesium alloy, which captured essential physics associated with pressurized solidification of multi-component system, including pressure-effect-embedded thermodynamic modeling (PEE thermodynamic modeling) and interactive diffusion. This model was applied to squeeze casting of a Mg-Al-Sn alloy and revealed that the applied pressure increased solute trapping and solute accumulation in front of solid/liquid interface, which are two opposite factors contributing to microsegregation. Governed by the mechanism, the microsegregation of solute Al aggravates with applied pressure considerably, while that of Sn is rarely influenced by the pressure.