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

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, epsilon(1), and the six fold term, epsilon(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 >. (C) 2011 Elsevier B.V. All rights reserved.