A simple model for short-range ordering kinetics in multi-principal element alloys

TL;DR

This paper introduces a simplified analytical model to predict the kinetics of short-range ordering in multi-principal element alloys, facilitating alloy design by estimating ordering relaxation times using readily available parameters.

Contribution

The paper presents a new isothermal concentration-wave model that accurately estimates SRO formation times using only mobility and thermodynamic data, simplifying previous approaches.

Findings

CW model estimates agree within a factor of five with kMC simulations.

Model requires only mobility and thermodynamic parameters.

Analytical nature aids in alloy processing design.

Abstract

Short-range ordering (SRO) in multi-principal element alloys influences material properties such as strength and corrosion. While some degree of SRO is expected at equilibrium, predicting the kinetics of its formation is challenging. We present a simplified isothermal concentration-wave (CW) model to estimate an effective relaxation time of SRO formation. Estimates from the CW model agree to within a factor of five with relaxation times obtained from kinetic Monte Carlo (kMC) simulations when above the highest ordering instability temperature. The advantage of the CW model is that it only requires mobility and thermodynamic parameters, which are readily obtained from alloy mobility databases and Metropolis Monte Carlo simulations, respectively. The simple parameterization of the CW model and its analytical nature make it an attractive tool for the design of processing conditions to promote or suppress SRO in multicomponent alloys.