Crystal-melt interface stresses: Atomistic simulation calculations for a Lennard-Jones binary alloy, Stillinger-Weber Si, and embedded atom method Ni

Molecular-dynamics and Monte Carlo simulations have been used to compute the crystal-melt interface stress (f) in a model Lennard-Jones (LJ) binary alloy system, as well as for elemental Si and Ni modeled by many-body Stillinger-Weber and embedded-atom-method (EAM) potentials, respectively. For the LJ alloys the interface stress in the (100) orientation was found to be negative and the f vs composition behavior exhibits a slight negative deviation from linearity. For Stillinger-Weber Si, a positive interface stress was found for both (100) and (111) interfaces: f₁₀₀=(380±30) mJ∕m² and f₁₁₁=(300±10) mJ∕m². The Si (100) and (111) interface stresses are roughly 80 and 65% of the value of the interfacial free energy (γ), respectively. In EAM Ni we obtained f₁₀₀=(22±74) mJ∕m², which is an order of magnitude lower than γ. A qualitative explanation for the trends in f is discussed.