Anomalous diffusion in dilute solid solutions

TitleAnomalous diffusion in dilute solid solutions
Publication TypeJournal Article
Year of Publication2007
AuthorsKrishnamurthy R, Srolovitz DJ, Mendelev MI
Journal TitleActa Materialia
Date PublishedSep
Type of ArticleArticle
ISBN Number1359-6454
Accession NumberISI:000249896100035
Keywordsal, impurities, MC simulation, model, molecular statics simulation, monte-carlo-simulation, ordering, RANDOM ALLOY, SHORT-RANGE

Diffusion in metals and alloys encapsulates many different physical phenomena and a range of time and length scales, and consequently, a hierarchical combination of simulation methods is required to study diffusion. We develop such methods to study the role interaction among defects and diffusants, and local association effects, play in diffusion in metals. We use Fe impurity diffusion in Al as an example. Using recently developed, accurate, interatomic potentials for the Fe-Al system, we calculate migration energies for atom-vacancy exchange in a variety of local atomic configurations, using lattice statics methods. These are used in a kinetic Monte-Carlo framework to calculate diffusivities. Two different activation regimes are observed at temperatures above and below 550 K. We explain this anomalous, non-Arrhenius behavior of the diffusion activation energy in terms of the interaction among vacancies and Fe atoms, and local association/ordering effects. (C) 2007 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Alternate JournalActa Mater.