Effect of Thermal Gradient on Phase Gibbs Free Energy

Recent studies on phase nucleation have demonstrated a dependence on undercooling and thermal gradients during transient phase transformations. Assuming a Representative Elementary Volume (REV), in which thermodynamic functions and thermophysical properties are well-defined within the framework of continuum mechanics, an increase in the thermal gradient leads to higher surface energy and Gibbs free energy. This reflects the relationship between the bulk and the surface area of the nucleus. In this work, the surface stress (ΣSL), bulk free energy (ΔGV), surface free energy (ΔGS), configurational free energy (ΔGC), entropy (ΔS), and undercooling (ΔT) are calculated as functions of the thermal gradient (∇T) for the FCC_A1 phase of an Al-Cu-Mg-Fe alloy.