Abstract
In order to facilitate a more widespread use of intermetallic γ-TiAl based alloys in the aircraft and automotive sector, recent research focuses on the development of low-cost titanium aluminides. The strong β-stabilizing effect as well as the increased ductility upon Mn addition renders this alloying element a promising candidate to fully or partially substitute other, more expensive, alloying elements such as Mo, Ta and Nb. Mn-containing γ-TiAl based alloys, however, are prone to the formation of the undesired, brittle Ti(Mn,Al) 2 C14 Laves phase during long-term exposure at the targeted service temperatures, which can deteriorate the ductility at ambient temperatures. In this study, the transformation kinetics as well as the chemical and thermal existence range of the C14 Laves phase in the low-cost Ti–42Al–5Mn (at.%) alloy were investigated by complementary experimental and computational approaches. In situ and ex situ high-energy X-ray diffraction in combination with microstructural investigations were used to study the occurrence and transformation kinetics of possible Laves phase formation in the course of annealing treatments. The chemical stability range of the C14 Laves phase was addressed by chemical analysis in conjunction with complementary ab initio modeling. Using these combined approaches, the critical local Mn concentration of ∼16 at.% for Laves phase formation within lamellar α 2 and ∼17 at.% within β o in the Ti–42Al–5Mn alloy was determined. These results should be critically considered for future design of advanced low-cost γ-TiAl based alloys.
| Originalsprache | Englisch |
|---|---|
| Aufsatznummer | 107962 |
| Seitenumfang | 9 |
| Fachzeitschrift | Intermetallics |
| Jahrgang | 2023 |
| Ausgabenummer | 161 |
| DOIs | |
| Publikationsstatus | Elektronische Veröffentlichung vor Drucklegung. - 11 Juni 2023 |
Bibliographische Notiz
Funding Information:We acknowledge DESY (Hamburg, Germany), a member of the Helmholtz Association HGF, for the provision of experimental facilities at PETRA III. The beamline P07 (HEMS) is operated by Helmholtz-Zentrum Hereon and we would like to thank Peter Staron, Norbert Schell and Emad Maawad for assistance in using the beamline and the dilatometer. Beamtime was allocated for proposal I-20200469 EC. The research leading to this result has been supported by the project CALIPSOplus under the Grant Agreement 730872 from the EU Framework Programme for Research and Innovation HORIZON 2020. The authors thank Reinhold Wartbichler for helpful assistance regarding the ThermoCalc calculations. The computational results presented have been achieved (in part) using the Vienna Scientific Cluster (VSC). L.H. and D.H. greatly acknowledge financial support by the Austrian Science Fund (FWF) Project No. P29731–N36. M.B. and D.K. acknowledge partial financial support by the Austrian Science Fund (FWF) Project No. P33823–N and the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program (Grant No. 771146 TOUGHIT). The authors greatly acknowledge the National Natural Science Foundation of China (Grant No. 51971215) for the funding of the ingot preparation.
Funding Information:
We acknowledge DESY (Hamburg, Germany), a member of the Helmholtz Association HGF, for the provision of experimental facilities at PETRA III. The beamline P07 (HEMS) is operated by Helmholtz-Zentrum Hereon and we would like to thank Peter Staron, Norbert Schell and Emad Maawad for assistance in using the beamline and the dilatometer. Beamtime was allocated for proposal I-20200469 EC. The research leading to this result has been supported by the project CALIPSOplus under the Grant Agreement 730872 from the EU Framework Programme for Research and Innovation HORIZON 2020. The authors thank Reinhold Wartbichler for helpful assistance regarding the ThermoCalc calculations. The computational results presented have been achieved (in part) using the Vienna Scientific Cluster (VSC). L.H. and D.H. greatly acknowledge financial support by the Austrian Science Fund ( FWF ) Project No. P29731–N36 . M.B. and D.K. acknowledge partial financial support by the Austrian Science Fund ( FWF ) Project No. P33823–N and the European Research Council ( ERC ) under the European Union's Horizon 2020 research and innovation program (Grant No. 771146 TOUGHIT ). The authors greatly acknowledge the National Natural Science Foundation of China (Grant No. 51971215 ) for the funding of the ingot preparation.
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