Atomistic Simulations of the Viscoelastic Response of a Model Single-Crystal Equiatomic Solid Solution

Abstract

We use molecular dynamics simulations of cyclic deformation to investigate the viscoelastic response of two-component, defect-free, face-centered cubic equiatomic solid solutions (ESSs). Rather than simulate a specific alloy composition, we use a Lennard-Jones model to study the effect of loading frequency, temperature, model size, and atomic misfit on mechanical energy dissipation. Although free of defects, these models exhibit viscoelastic behavior. We attribute this behavior to the large distortion in the lattice structure induced by atomic misfit. Peaks in loss modulus-frequency plots are due to resonant vibrations occurring at specific frequencies. Moreover, the elastic storage moduli of our ESS models are found to be misfit dependent. Our findings may aid future research in mechanical behavior of concentrated alloys and in molecular dynamics simulations of viscoelastic behavior.