Microscopic Modeling of the Growth of Order in an Alloy: Nucleated and Continuous Ordering

TL;DR

This paper models early-stage ordering in Cu3Au alloys using a microscopic Hamiltonian, revealing a crossover in growth regimes and aligning with experimental observations of nucleated and continuous ordering.

Contribution

It introduces a microscopic model based on effective medium theory to simulate alloy ordering, providing new insights into early-stage kinetics and growth regimes.

Findings

Crossover from nucleated to continuous growth regimes

Semi-quantitative agreement with experimental growth kinetics

Real-space structures reveal early-stage kinetic mechanisms

Abstract

We study the early-stages of ordering in $Cu_3 Au$ using a model Hamiltonian derived from the effective medium theory of cohesion in metals: an approach providing a microscopic description of interatomic interactions in alloys. Our simulations show a crossover from a nucleated growth regime to a region where the ordering does not follow any simple growth laws. This mirrors the experimental observations in $Cu_3 Au$. The kinetics of growth, obtained from the simulations, is in semi-quantitative agreement with experiments. The real-space structures observed in our simulations offer some insight into the nature of early-stage kinetics