Anisotropy in interface stress at the BCC-iron solid-melt interface: molecular dynamics and phase field crystal modelling

TL;DR

This study compares molecular dynamics and phase field crystal models to evaluate anisotropic interface stress at the BCC-iron solid-melt interface, revealing qualitative agreement but quantitative differences, with implications for nanoscale material properties.

Contribution

It demonstrates that MD and PFC models can evaluate interface stress anisotropy, with PFC providing quantitatively consistent results, advancing modeling approaches for BCC-iron interfaces.

Findings

MD and PFC results are qualitatively similar

Quantitative results differ between MD and PFC

Strong anisotropy affects nanoscale properties

Abstract

The interface stresses at of the solid-melt interface are, in general, anisotropic. The anisotropy in the interfacial stress can be evaluated using molecular dynamics (MD) and phase field crystal (PFC) models. In this paper, we report our results on the evaluation of the anisotropy in interface stress in a BCC solid with its melt. Specifically, we study Fe using both MD and PFC models. We show that while both MD and PFC can be used for the evaluation, and the PFC and the amplitude equations based on PFC give quantitatively consistent results, the MD and PFC results are qualitatively the same but do not match quantitatively. We also find that even though the interfacial free energy is only weakly anisotropic in BCC interfacial stress anisotropy is strong. This strong anisotropy has implications for the equilibrium shapes, growth morphologies and other properties at nano-scale in these materials.