Influence of Nb on Ti diffusion in γ-TiAl intermetallics studied by mechanical spectroscopy

J. Ibanez-Perez, Maria L. No, M. Oehring, Helmut Clemens, J.M. San Juan

Publikation: Beitrag in FachzeitschriftArtikelForschungBegutachtung

1 Zitat (Scopus)

Abstract

The development of intermetallic titanium aluminides has been driven by the aeronautic and aerospace industries because of the excellent mechanical properties and low density of γ-TiAl based alloys. Up to now, several generations of γ-TiAl based alloys were developed with increasing complexity of the alloy systems. Nb is one of the most important alloying elements in γ-TiAl alloys and although it is considered as a slow diffuser, its influence has not been fully quantified yet. In this work we demonstrate, through mechanical spectroscopy measurements conducted on several γ-TiAl based alloys with different Nb content, that Nb impedes the diffusion of Ti atoms in the α 2-Ti 3Al phase. Internal friction measurements show a relaxation peak P(α 2), which is associated with short distance diffusion of Ti atoms in the α 2 phase, involving stress-induced rotation of dipoles Al-V Ti-Al, whose activation energy is dependent on the Nb content. The increase of the activation energy is quantified as ΔE a(Ti)= 0.037 eV × at% Nb, being attributed to the next-neighbor interaction of Nb atoms with the local configuration of Ti-V Ti. This mechanism also produces a further broadening of the relaxation peak, which is attributed to the near-next-neighbor interactions for high Nb contents. Finally, an atomic model for the mechanism responsible for this relaxation is proposed allowing to explain the observed experimental behavior.

OriginalspracheEnglisch
Aufsatznummer158880
Seitenumfang8
FachzeitschriftJournal of alloys and compounds
Jahrgang867.2021
AusgabenummerJune
Frühes Online-Datum2 Feb. 2021
DOIs
PublikationsstatusVeröffentlicht - 25 Juni 2021

Bibliographische Notiz

Funding Information:
The authors thank the financial support from the MINECO , Spain, project CONSOLIDER-INGENIO 2010 CSD2009–00013, as well as by the Consolidated Research Group GIU-17/071 from the University of the Basque Country , UPV/EHU , Spain, and the project ETORTEK CEMAP from the Industry Department of Basque Government , Spain. This work made use of the facilities of the SGIKER from the UPV/EHU, Spain.

Publisher Copyright:
© 2021 The Author(s)

Dieses zitieren