Effect of Impurities on the Formation Energy of Point Defects in the γ-TiAl Alloy

Journal Article · Sat Dec 15 04:00:00 EST 2018 · Journal of Experimental and Theoretical Physics

DOI:https://doi.org/10.1134/S1063776118120130· OSTI ID:22917837

Kulkova, S. E. ^[1]

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1. National Research Tomsk State University (Russian Federation)

The projector augmented-wave method within density functional theory is used to study the effect of 4d elements and Group IIIA and IVA elements on the energetics of point defect formation and elastic moduli of the γ-TiAl alloy. To calculate the point defect formation energy, the grand canonical formalism was used. It is shown that the formation energy of aluminum vacancies decreases by approximately 1.3 eV with increasing its content in the series of alloys Ti{sub 3}Al–TiAl–TiAl{sub 3}, whereas the formation energy of titanium vacancies changes insignificantly. In general, the formation of titanium vacancies in these alloys is preferred to the formation of aluminum vacancies. It has been found that Nb, Mo, Tc, Ru, Rh, and Pd impurities on the aluminum sublattice contribute to an increase in the formation energy of an aluminum vacancies, and Mo and Tc also lead to an increase in the formation energy of titanium vacancies. All 4d impurities, if they substitute for titanium, reduce the formation energy of aluminum vacancies, and Nb and Mo are favorable for increasing the formation energy of titanium vacancies. The influence of impurities on the chemical bond in the γ-TiAl alloy and its elastic moduli and characteristics based on them is discussed.

• OSTI ID: 22917837
• Journal Information: Journal of Experimental and Theoretical Physics, Journal Name: Journal of Experimental and Theoretical Physics Journal Issue: 6 Vol. 127; ISSN JTPHES; ISSN 1063-7761
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALUMINIUM COMPOUNDS
APPROXIMATIONS
BINARY ALLOY SYSTEMS
CHEMICAL BONDS
DENSITY FUNCTIONAL METHOD
IMPURITIES
POINT DEFECTS
TITANIUM COMPOUNDS