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Séparation de Phase dans les Alliages Al-Zr-Sc: du Saut des Atomes à la Croissance de Précipités Ordonnés

Abstract : Zirconium and scandium addition to aluminium alloys leads to the formation of ordered precipitates. This study aims to a better understanding of precipitation kinetics thanks to an approach combining atomic and mesoscopic models. An experimental work has been undertaken too so as to characterize by transmission electron microscopy Al3Zr kinetics of precipitation.

We mainly focus on the nucleation stage and, in this purpose, an atomic model lying on a rigid lattice has been built for Al-Zr-Sc system allowing us to study precipitation with kinetic Monte Carlo simulations. While keeping the vacancy exchange mechanism for diffusion, we introduce multi-site interactions, going thus beyond
a simple pair interaction model, and test the influence of these interactions on kinetics of precipitation. The comparison between Monte Carlo simulations and classical nucleation theory shows that mesoscopic models can lead to a good description of the nucleation stage of Al3Zr and Al3Sc as long as the order tendency of the system has been taken into account to calculate input parameters of these models. For the ternary Al-Zr-Sc system, atomic simulations
allow a better understanding of the precipitation kinetic path. It is then possible to extend the field of classical nucleation theory so as to model nucleation in a ternary alloy where the stoichiometry of the precipitates is unknown.
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Contributor : Emmanuel Clouet <>
Submitted on : Friday, March 10, 2006 - 3:28:30 PM
Last modification on : Thursday, June 25, 2020 - 2:54:03 PM
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Emmanuel Clouet. Séparation de Phase dans les Alliages Al-Zr-Sc: du Saut des Atomes à la Croissance de Précipités Ordonnés. Analyse de données, Statistiques et Probabilités [physics.data-an]. Ecole Centrale Paris, 2004. Français. ⟨tel-00005967v3⟩

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