Atomistic Simulation Study of the FCC and BCC Crystal-Melt Interface Stresses

Abstract

In this work, molecular dynamics simulations have been used to undertake a computational study of the equilibrium crystal-melt interface stresses in face-centered-cubic (FCC) Ni and body-centered-cubic (BCC) Fe, BCC Nb, and a model BCC soft-sphere elemental system, for three different interface orientations, i.e., (100), (110), and (111). The sign, magnitude, and anisotropy of the excess interface stresses and their relationships with the corresponding interfacial free energies have been examined. The universality of a few trends regarding the interfacial stresses observed in FCC crystal-melt interfaces has been assessed for the BCC crystal-melt interfaces. The role of the interatomic bonding that affects the shape of the interfacial stress profiles, thus modulating the magnitude or sign of the excess interface stress, has been discussed through inspecting a particular type of crystal-melt interface over different materials. Besides, for the first time, we have demonstrated that the Irving-Kirkwood fine-grained algorithm for depicting microscopic pressure components and stresses in the vicinity of the crystal-melt interface is superior to the previously used per-particle virial stress algorithm. The reported data and new knowledgqe could enrich the accumulation for theory breakthroughs in predicting interface stresses and motivate future studies on the interfacial stresses for more types of solid-liquid interfaces.