Atomistic modeling of carbon Cottrell atmospheres in bcc iron

Atomistic simulations with an EAM interatomic potential were used to evaluate carbon-dislocation binding energies in bcc iron. These binding energies were then used to calculate the occupation probability of interstitial sites in the vicinity of an edge and a screw dislocation. The saturation concen...

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Bibliographic Details
Published in:Journal of physics. Condensed matter 2013-01, Vol.25 (2), p.025401-025401
Main Authors: Veiga, R G A, Perez, M, Becquart, C S, Domain, C
Format: Article
Language:English
Subjects:
Atmospheres
Binding energy
Carbon
Carbon - chemistry
Computer Simulation
Condensed matter
Condensed matter: structure, mechanical and thermal properties
Defects and impurities in crystals
microstructure
Dislocations
Edge dislocations
Energy Transfer
Engineering Sciences
Exact sciences and technology
Iron
Iron - chemistry
Linear defects: dislocations, disclinations
Materials
Mathematical models
Models, Chemical
Models, Molecular
Physics
Pressure
Structure of solids and liquids
crystallography
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Summary:Atomistic simulations with an EAM interatomic potential were used to evaluate carbon-dislocation binding energies in bcc iron. These binding energies were then used to calculate the occupation probability of interstitial sites in the vicinity of an edge and a screw dislocation. The saturation concentration due to carbon-carbon interactions was also estimated by atomistic simulations in the dislocation core and taken as an upper limit for carbon concentration in a Cottrell atmosphere. We obtained a maximum concentration of 10 ± 1 at.% C at T = 0 K within a radius of 1 nm from the dislocation lines. The spatial carbon distributions around the line defects revealed that the Cottrell atmosphere associated with an edge dislocation is denser than that around a screw dislocation, in contrast with the predictions of the classical model of Cochardt and colleagues. Moreover, the present Cottrell atmosphere model is in reasonable quantitative accord with the three-dimensional atom probe data available in the literature.
ISSN:0953-8984
1361-648X
DOI:10.1088/0953-8984/25/2/025401