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abstract: 'Using an atom–vacancy exchange algorithm, we investigate the kinetics of the order–disorder transition in an fcc $A_3B$ binary alloy model following a temperature quench from the disordered phase. We observe two clearly distinct ordering scenarios depending on whether the final temperature $T_f$ falls above or below the ordering spinodal $T_{sp}$, which is deduced from simulations at equilibrium. For shallow quenches ($T_f>T_{sp}$) we identify an incubation time $\tau_{inc}$ which characterizes the onset of ordering through the formation of overcritical ordered nuclei. The algorithm we use together with experimental information on tracer diffusion in Cu$_3$Au alloys allows us to estimate the physical time scale connected with $\tau_{inc}$ in that material. Deep quenches, $T_f<T_{sp}$, result in spinodal ordering. Coarsening processes at long times proceed substantially slower than predicted by the Lifshitz–Allen–Cahn $t^{1/2}$ law. Structure factors related to the geometry of the two types of domain walls that appear in our model are found to be consistent with Porod’s law in one and two dimensions.'
author:
- 'M. Kessler,$^1$ W. Dieterich,$^1$ and A. Majhofer$^2$'
date: 24 July 2002
title: 'Ordering kinetics in an fcc $A_3B$ binary alloy model: Monte Carlo studies.'
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Introduction
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Several face–centered cubic binary metallic alloys, like Cu$_3$Au, 