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Monte Carlo simulations of precipitation of $L1_2$

Abinandanan, TA and Haider, F and Martin, G (1994) Monte Carlo simulations of precipitation of $L1_2$. In: Proceedings of an International Conference on Solid-Solid Phase Transformations, 17-22 July 1994, Framington, PA, USA, pp. 443-448.

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Abstract

Precipitation of an $A_3B$ ordered phase (with an $L1_2$ structure) from a supersaturated, disordered fcc phase has been studied using a novel Monte Carlo (MC) technique, in which atomic transport takes place through vacancy migration. A single vacancy is introduced in the fcc lattice for this purpose. This MC technique, in combination with a stochastic formulation of chemical kinetics, allows us to define “time�? in a physically meaningful way. Thus, our simulations are more realistic than those which use atom-exchange mechanism for diffusion and define time in terms of number of MC steps. The A-B interaction potentials in the fcc lattice extend up to second nearest neighbours, and are chosen such that the phase diagram shows disordered fcc and ordered $L1_2$ and $L1_0$ phases. Our simulations of precipitation of the $L1_2$ phase from the disordered fcc phase indicate that phase separation and ordering take place simultaneously, and on similar time scales, even for a concentrated alloy (which has about 47 volume percent of the ordered phase in equilibrium at the transformation temperature). During late stages, the precipitates of the ordered phase undergo coarsening, obeying the classical scaling laws applicable for this regime

Item Type: Conference Paper
Additional Information: Copyright of this article belongs to TMS - Minerals Metals & Materials Society.
Keywords: Monte Carlo methods;order disorder transformations; precipitation;self diffusion;vacancies (crystal)
Department/Centre: Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited: 19 Nov 2007
Last Modified: 11 Jan 2012 10:06
URI: http://eprints.iisc.ernet.in/id/eprint/11051

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