Phase transformations and phase stability in the Ti–44 at.%Al–(0–7 at.%) Mo system

Michael Musi, Helmut Clemens, Andreas Stark, Peter Staron, Petra Spörk-Erdely

Publikation: Beitrag in FachzeitschriftArtikelForschungBegutachtung

Abstract

Molybdenum is an excellent candidate to study the effect of β-stabilizing elements on the phase transitions in intermetallic γ-TiAl based alloys. In the present work, two model alloys based on the Ti–44Al (at.%) system containing 1 at.% and 5 at.% Mo are investigated. Examinations of the microstructures after casting and subsequent heat treatments reveal significant differences in the morphology and amount of the phases present and, thus, highlight the effect of Mo on the different phase transformations near and far from thermodynamic equilibrium. In-situ high-energy X-ray diffraction and differential scanning calorimetry were employed to identify the occurring phases and determine the phase transition temperatures in the two model alloys. Especially, the β phase was found to be strongly impacted by the Mo content of the alloys. While the β phase is only present at high temperatures in the Ti–44Al–1Mo alloy, it is thermodynamically stable from the liquidus temperature downwards to room temperature in the Ti–44Al–5Mo alloy. Long-term heat treatments for 30 days at 1000 °C were conducted to determine the phase equilibria at intermediate temperatures. Ultimately, the findings of this work were combined with data from literature to reassess the quasi-binary Ti–44Al–(0–7)Mo (at.%) phase diagram.

OriginalspracheEnglisch
Aufsatznummer107484
Seitenumfang9
FachzeitschriftIntermetallics
Jahrgang143.2022
AusgabenummerApril
Frühes Online-Datum2 Feb. 2022
DOIs
PublikationsstatusVeröffentlicht - Apr. 2022

Bibliographische Notiz

Funding Information:
This research was funded in part by the Austrian Science Fund (FWF) [Project Number I 3932-N36 ]. For the purpose of open access, the author has applied a CC BY public copyright licence to any Author Accepted Manuscript version arising from this submission. M. Musi is a Recipient of a DOC Fellowship of the Austrian Academy of Sciences at the Department of Materials Science, Montanuniversität Leoben. We acknowledge DESY (Hamburg, Germany), a member of the Helmholtz Association HGF, for the provision of experimental facilities. Parts of this research were carried out at DORIS III and we would like to thank Thomas Schmoelzer and Svea Mayer for assistance in the performed in-situ HEXRD experiments.

Funding Information:
This research was funded in part by the Austrian Science Fund (FWF) [Project Number I 3932-N36]. For the purpose of open access, the author has applied a CC BY public copyright licence to any Author Accepted Manuscript version arising from this submission. M. Musi is a Recipient of a DOC Fellowship of the Austrian Academy of Sciences at the Department of Materials Science, Montanuniversit?t Leoben. We acknowledge DESY (Hamburg, Germany), a member of the Helmholtz Association HGF, for the provision of experimental facilities. Parts of this research were carried out at DORIS III and we would like to thank Thomas Schmoelzer and Svea Mayer for assistance in the performed in-situ HEXRD experiments.

Publisher Copyright:
© 2022 The Authors

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