A molecular dynamics simulation study of the crystal–melt interfacial free energy and its anisotropy in the Cu–Ag–Au ternary system

Abstract

The crystal–melt interfacial free energy and its small anisotropy were computed using molecular dynamics simulations and the capillary fluctuation method applied to an embedded atom description of the ternary Cu–Ag–Au alloy system. The use of a ternary system allows for an assessment of the variation in anisotropy as one solute species (Au) is replaced by a nearly equal atomic size species (Ag) at a constant temperature, thereby isolating the effect of solute–solvent binding characteristics. Both the four-fold anisotropy parameter, ε 1 , and the six fold term, ε 2 , were computed for five compositions within the Gibbs triangle at T = 1275 K . The results suggest that solute species exhibiting a large enthalpy of mixing will tend to promote a transition of the dendrite crystallographic growth directions from 〈 1 0 0 〉 to 〈 1 1 0 〉 .