Microscopic Treatment of Solute Trapping and Drag

TL;DR

This paper derives an analytical model for solute trapping and drag in binary alloys using a microscopic phase field crystal theory, providing new insights and supporting previous simulation results.

Contribution

It presents the first analytical derivation of solute segregation and drag from a microscopic model, linking microscopic theory to macroscopic phenomena.

Findings

Analytical expression for segregation coefficient as a function of interface velocity.

Support for previous molecular dynamics and PFC simulation results.

Provides a new theoretical framework based on classical density functional theory.

Abstract

The long wavelength limit of a recent microscopic phase field crystal (PFC) theory of a binary alloy mix- ture is used to derive an analytical approximation for the segregation coefficient as a function of the interface velocity, and relate it to the two-point correlation function of the liquid and the thermodynamic properties of solid and liquid phases. Our results offer the first analytic derivation of solute segregation and solute drag de- rived from a microscopic model, and analytically support recent molecular dynamics and fully numerical PFC simulations. Our analytical result also provides an independent framework, motivated from classical density functional theory, from which to elucidate the fundamental nature of solute drag, which is still highly contested in the literature.