Monte Carlo Study of Ordering and Domain Growth in a Class of fcc-Alloy Models

TL;DR

This study uses Monte Carlo simulations to analyze ordering and domain growth in fcc-alloys with A_3B composition, revealing how second-neighbor interactions influence growth rates and domain evolution.

Contribution

It introduces a lattice model with NN and NNN interactions to simulate domain growth in fcc-alloys and compares growth dynamics with theoretical predictions.

Findings

Zero NNN-interactions lead to slow domain growth with exponent ~1/4.

Increasing NNN-interactions accelerates growth, approaching an exponent of 1/2.

Growth behavior aligns with Lifshitz-Allen-Cahn theory at higher NNN-interactions.

Abstract

Ordering processes in fcc-alloys with composition A_3B (like Cu_3Au, Cu_3Pd, CoPt_3 etc.) are investigated by Monte Carlo simulation within a class of lattice models based on nearest-neighbor (NN) and second-neighbor (NNN) interactions. Using an atom-vacancy exchange algorithm, we study the growth of ordered domains following a temperature quench below the ordering spinodal. For zero NNN-interactions we observe an anomalously slow growth of the domain size L(t) \sim t^\alpha, where \alpha \sim 1/4 within our accessible timescales. With increasing NNN-interactions domain growth becomes faster and \alpha gradually approaches the value 1/2 as predicted by the conventional Lifshitz-Allen-Cahn theory.