Diffusion Properties of Oxygen in the γ-TiAl Alloy

The oxygen absorption and migration energies in the γ-TiAl alloy are calculated using the projector augmented-wave method within the density functional theory. The phonon frequencies required for estimating the average jump rate are determined at initial and saddle oxygen positions. The temperature-...

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Bibliographic Details
Published inJournal of experimental and theoretical physics Vol. 130; no. 4; pp. 579 - 590
Main Authors Bakulin, A. V., Kulkov, S. S., Kulkova, S. E.
Format Journal Article
LanguageEnglish
Published Moscow Pleiades Publishing 01.04.2020
Springer Nature B.V
Subjects
Classical and Quantum Gravitation
Density functional theory
Diffusion coefficient
Diffusion rate
Disorder
Elementary Particles
Intermetallic compounds
Order
Oxygen
Particle and Nuclear Physics
Phase Transition in Condensed System
Physics
Physics and Astronomy
Quantum Field Theory
Relativity Theory
Solid State Physics
Statistical methods
Temperature dependence
Titanium aluminides
Titanium base alloys
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Summary:The oxygen absorption and migration energies in the γ-TiAl alloy are calculated using the projector augmented-wave method within the density functional theory. The phonon frequencies required for estimating the average jump rate are determined at initial and saddle oxygen positions. The temperature-dependent diffusion coefficient, the activation energy, and preexponential factor D 0 are calculated along axes a and c using two models, which differ in oxygen interstitial positions, and two methods (statistical, Landman). The factors that determine the temperature-dependent diffusion coefficient in the Landman model are found. On the whole, the diffusion coefficients calculated within both methods are shown to agree satisfactorily; however, the Landman model can overestimate the contributions of low-barrier paths.
ISSN:1063-7761
1090-6509
DOI:10.1134/S1063776120030115