Role of impurities in the formation of point defects in Ti-Al alloys

Functional Materials and Nanotechnologies 2018

Bakulin, A.V.^1^2 ; Fuks, A.A.^1 ; Kulkova, S.E.^1^2

National Research Tomsk State University, pr. Lenina 36, Tomsk

634050, Russia^1

Institute of Strength Physics and Materials Science, Russian Academy of Sciences, Siberian Branch, pr. Akademichesky 2/4, Tomsk

634055, Russia^2

关键词: Defect formation energies;    Formation energies;    Grand-canonical formalism;    Impurities in;    Projector augmented waves;    TiAl alloy;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/503/1/012003/pdf
DOI  :  10.1088/1757-899X/503/1/012003

来源: IOP

【 摘 要 】

The effect of impurities on the point defect formation energies in Ti-Al alloys was studied by the projector augmented-wave method. The grand canonical formalism was applied to calculate the formation energies of several kinds of defects. It was shown that the formation energy of Al-vacancy decreases by ∼1.3 eV with increasing its content in the series of alloys Ti3Al-TiAl-TiAl3, whereas the formation energy of Ti-vacancy changes insignificantly. In general, the formation of Ti-vacancies is more preferred in Ti-Al alloys rather than the formation of Al-vacancies. We demonstrate that Nb, Mo, Tc, Ru, Rh, Pd lead to increase of the formation energy of Al-vacancy if they occupy the Al sites, whereas only Mo and Tc increase the formation energy of Ti-vacancy. All 4d elements, if they substitute for Ti, reduce the formation energies of Al-vacancy. The influence of impurities on elastic constants is discussed.