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Diffusion of yttrium in bcc-iron studied by kinetic Monte Carlo simulations

Mock, Markus and Albe, Karsten (2017):
Diffusion of yttrium in bcc-iron studied by kinetic Monte Carlo simulations.
In: Journal of Nuclear Materials, Elsevier, pp. 157-164, 494, ISSN 00223115,
DOI: 10.1016/j.jnucmat.2017.07.021,
[Online-Edition: https://doi.org/10.1016/j.jnucmat.2017.07.021],
[Article]

Abstract

The formation of oxide nanoclusters in oxide dispersion strengthened steels is controlled by the diffusion of yttrium. Yttrium atoms and other oversized solutes show a high binding energy to vacancies and a considerable relaxation from their lattice site towards a neighboring vacancy. In the case of yttrium the relaxation is so prominent, that the resulting situation may also be considered as an interstitial atom sitting in between two vacancies. We calculated the yttrium-vacancy binding energy and the migration barriers of vacancy jumps in the vicinity of a yttrium atom by means of nudged-elastic band calculations using density functional theory calculations. These barriers were used in a kinetic Monte Carlo code to calculate the diffusivity of yttrium and investigate the diffusion mechanism of yttrium in bcc iron with focus on correlation effects. The results reveal that the diffusion of yttrium is due to a sequence of vacancy jumps between the nearest and third nearest neighbor shell of the yttrium atom.

Item Type: Article
Erschienen: 2017
Creators: Mock, Markus and Albe, Karsten
Title: Diffusion of yttrium in bcc-iron studied by kinetic Monte Carlo simulations
Language: English
Abstract:

The formation of oxide nanoclusters in oxide dispersion strengthened steels is controlled by the diffusion of yttrium. Yttrium atoms and other oversized solutes show a high binding energy to vacancies and a considerable relaxation from their lattice site towards a neighboring vacancy. In the case of yttrium the relaxation is so prominent, that the resulting situation may also be considered as an interstitial atom sitting in between two vacancies. We calculated the yttrium-vacancy binding energy and the migration barriers of vacancy jumps in the vicinity of a yttrium atom by means of nudged-elastic band calculations using density functional theory calculations. These barriers were used in a kinetic Monte Carlo code to calculate the diffusivity of yttrium and investigate the diffusion mechanism of yttrium in bcc iron with focus on correlation effects. The results reveal that the diffusion of yttrium is due to a sequence of vacancy jumps between the nearest and third nearest neighbor shell of the yttrium atom.

Journal or Publication Title: Journal of Nuclear Materials
Volume: 494
Publisher: Elsevier
Uncontrolled Keywords: Kinetic Monte Carlo, Oxide dispersion strengthened, Diffusion
Divisions: 11 Department of Materials and Earth Sciences > Material Science > Materials Modelling
Zentrale Einrichtungen > University IT-Service and Computing Centre (HRZ) > Hochleistungsrechner
11 Department of Materials and Earth Sciences > Material Science
Zentrale Einrichtungen > University IT-Service and Computing Centre (HRZ)
11 Department of Materials and Earth Sciences
Zentrale Einrichtungen
Date Deposited: 02 Feb 2018 08:49
DOI: 10.1016/j.jnucmat.2017.07.021
Official URL: https://doi.org/10.1016/j.jnucmat.2017.07.021
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