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Theoretical study of oxygen insertion and diffusivity in the g-TiAl L10 system

Connétable, Damien and Prillieux, Aurélien and Thenot, Camille and Monchoux, Jean-Philippe Theoretical study of oxygen insertion and diffusivity in the g-TiAl L10 system. (2020) Journal of Physics : Condensed Matter, 32 (17). 175702. ISSN 0953-8984

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Official URL: https://doi.org/10.1088/1361-648X/ab6a2f

Abstract

This work is a first-principles study of the insertion and diffusivity of oxygen in the -TiAl L10 system. Five interstitial positions were identified as stable. One, however, the 2h site a pyramid composed of a Ti square topped by an Al atom, was found more stable than the others. The oxygen interactions with the TiAl system were thus studied and analyzed in detail using vibrational, elastic and electronic properties. The results show that the O atom prefers to be surrounded by Ti atoms and tries to minimize the number of bonds with aluminum. The diffusion mechanism is subsequently studied at the atomic scale, by analyzing displacements between stable interstitial sites. The oxygen diffusivity is found to be anisotropic and the components in the x and z direction, Dx and Dz, are then calculated and compared with those of O diffusion into other Ti–Al alloys. The analysis of results shows two effects. First, the stability of sites is related to the number of O–Al bonds, the fewer there are, the more stable the site is, and second, the diffusion is faster when the content of interstitial sites composed of many Ti atoms is low

Item Type:Article
HAL Id:hal-03031898
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE)
Université de Toulouse > Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE)
Université de Toulouse > Université Toulouse III - Paul Sabatier - UT3 (FRANCE)
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Deposited On:12 Nov 2020 16:19

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