Phase-Field Crystal Model for Fe Connected to MEAM Molecular Dynamics Simulations

Abstract

A recently developed phase-field crystal (PFC) model incorporates elasticity and plasticity in the microstructural evolution of materials naturally by representing the density field for the crystalline state by periodic functions and by using a constant density for liquid state. PFC is of great interest in nano- and micro-structural modeling of materials because it is a model with atomistic scale details but is applicable to diffusive time scales. However, determining model parameters for specific materials is one of the less developed aspects of PFC modeling. In this article, molecular dynamics (MD) simulations of solid–liquid structures for Fe were performed using the modified embedded-atom method to determine the melting point, latent heat, expansion in melting, density profile, and liquid structure factor. The influence of simulation cell size on the results of MD simulations was also investigated. The melting temperature, density profile, and liquid structure factor were used as inputs to find model parameters required by the PFC model for Fe. The spatial derivative order of the PFC time-evolution equation was reduced from four to two, and the resultant system of partial differential equations was solved numerically using the finite element method. The required simulation domain and element size for the convergence of the PFC simulations were determined, and the expansion in melting, latent heat and solid–liquid surface free energy were calculated. The PFC results were compared with the results of other computational and experimental works in the literature.