Theoretical study of oxygen sorption and diffusion in the volume and on the surface of a γ-TiAl alloy

Journal Article · Sun Feb 15 04:00:00 EST 2015 · Journal of Experimental and Theoretical Physics

DOI:https://doi.org/10.1134/S1063776115020090· OSTI ID:22472391

Kulkova, S. E. ^[1]; Hu, Q. M.; Yang, R. ^[2]

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1. Russian Academy of Sciences, Institute of Strength Physics and Materials Science, Siberian Branch (Russian Federation)
2. Chinese Academy of Sciences, National Laboratory for Materials Science, Institute of Metal Research (China)

The oxygen sorption on the low-index (001), (100), and (110) surfaces of a γ-TiAl alloy is studied by the pseudopotential method with the generalized gradient approximation for the exchange-correlation functional. The most preferred sites for oxygen sorption in the bulk and on the surface of the alloy are determined. The titanium-rich octahedral site is shown to be preferred for oxygen sorption in the bulk material. The effect of the oxygen concentration on the atomic and electronic structures of the stoichiometric TiAl(100) surface is studied. It is shown that, at the first stage of oxidation, oxygen prefers to form bonds with titanium. The energy barriers for oxygen diffusion on the stoichiometric (100) surface and in the bulk of the material are calculated. The energy barriers are shown to depend substantially on the local environments of oxygen and to increase during diffusion from titanium-rich sites. The most possible mechanism of oxygen diffusion from the (100) surface to the bulk of the material is oxygen migration through tetrahedral sites.

• OSTI ID: 22472391
• Journal Information: Journal of Experimental and Theoretical Physics, Journal Name: Journal of Experimental and Theoretical Physics Journal Issue: 2 Vol. 120; ISSN JTPHES; ISSN 1063-7761
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM ALLOYS
CHEMICAL BONDS
CONCENTRATION RATIO
CRYSTAL STRUCTURE
ELECTRONIC STRUCTURE
OXIDATION
POTENTIALS
SORPTION
STOICHIOMETRY
SURFACES
TITANIUM ALLOYS