Crack resistance of α2|γ and γ|γ interfaces within a TiAl alloy determined by in situ nano-fracture experiments

This study examines the fracture behavior and mechanisms of a TiAl alloy by assessing individual α2|γ and γ|γ interfaces as well as individual α2 and γ lamellae through in situ nano-mechanical investigations. Utilizing a TNM+ TiAl alloy with a fully lamellar microstructure, notched bending beams wer...

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Main Authors: Michael Burtscher, Simon Fellner, Christoph Gammer, Markus Alfreider, Daniel Kiener
Format: Article
Language:English
Published: Elsevier 2025-07-01
Series:Journal of Materials Research and Technology
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Online Access:http://www.sciencedirect.com/science/article/pii/S2238785425017053
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author Michael Burtscher
Simon Fellner
Christoph Gammer
Markus Alfreider
Daniel Kiener
author_facet Michael Burtscher
Simon Fellner
Christoph Gammer
Markus Alfreider
Daniel Kiener
author_sort Michael Burtscher
collection DOAJ
description This study examines the fracture behavior and mechanisms of a TiAl alloy by assessing individual α2|γ and γ|γ interfaces as well as individual α2 and γ lamellae through in situ nano-mechanical investigations. Utilizing a TNM+ TiAl alloy with a fully lamellar microstructure, notched bending beams were tested within a transmission electron microscope to assess their mechanical response and type of fracture. The notched specimens were prepared to enable real-time observation of crack initiation and propagation along these distinct interfaces and phases. Results indicate that α2|γ interfaces demonstrate a more brittle response, while γ|γ interfaces exhibit increased fracture resistance. This could be attributed to dislocation emissions and crack tip blunting within the γ phase. The notched γ lamella exhibited enhanced plastic deformation, as evidenced by higher conditional J integral values of 100 J/m2. In contrast, the notched α2 lamellae reached 35 J/m2 due to limited available glide systems and easy cleavage of the basal plane. Hence, the α2 phase decreases ductility and promotes a brittle fracture. Thus, this study enhances the understanding of how specific interfaces and phases affect failure tolerance in TiAl alloys. These insights could guide the design rules of TiAl alloys with improved fracture toughness and reliability for demanding structural applications.
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institution Kabale University
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spelling doaj-art-797cd31313804ccebd1513fd1727d1eb2025-08-20T03:50:07ZengElsevierJournal of Materials Research and Technology2238-78542025-07-01373541354810.1016/j.jmrt.2025.07.047Crack resistance of α2|γ and γ|γ interfaces within a TiAl alloy determined by in situ nano-fracture experimentsMichael Burtscher0Simon Fellner1Christoph Gammer2Markus Alfreider3Daniel Kiener4Department of Materials Science, Montanuniversität Leoben, Jahnstraße 12, 8700, Leoben, Austria; Corresponding author.Erich Schmid Institute of Materials Science, Austrian Academy of Sciences (ÖAW), Jahnstraße 12, 8700, Leoben, AustriaErich Schmid Institute of Materials Science, Austrian Academy of Sciences (ÖAW), Jahnstraße 12, 8700, Leoben, AustriaDepartment of Materials Science, Montanuniversität Leoben, Jahnstraße 12, 8700, Leoben, AustriaDepartment of Materials Science, Montanuniversität Leoben, Jahnstraße 12, 8700, Leoben, AustriaThis study examines the fracture behavior and mechanisms of a TiAl alloy by assessing individual α2|γ and γ|γ interfaces as well as individual α2 and γ lamellae through in situ nano-mechanical investigations. Utilizing a TNM+ TiAl alloy with a fully lamellar microstructure, notched bending beams were tested within a transmission electron microscope to assess their mechanical response and type of fracture. The notched specimens were prepared to enable real-time observation of crack initiation and propagation along these distinct interfaces and phases. Results indicate that α2|γ interfaces demonstrate a more brittle response, while γ|γ interfaces exhibit increased fracture resistance. This could be attributed to dislocation emissions and crack tip blunting within the γ phase. The notched γ lamella exhibited enhanced plastic deformation, as evidenced by higher conditional J integral values of 100 J/m2. In contrast, the notched α2 lamellae reached 35 J/m2 due to limited available glide systems and easy cleavage of the basal plane. Hence, the α2 phase decreases ductility and promotes a brittle fracture. Thus, this study enhances the understanding of how specific interfaces and phases affect failure tolerance in TiAl alloys. These insights could guide the design rules of TiAl alloys with improved fracture toughness and reliability for demanding structural applications.http://www.sciencedirect.com/science/article/pii/S2238785425017053IntermetallicsFracture mechanicsTiAlInterfacesIn situ TEM
spellingShingle Michael Burtscher
Simon Fellner
Christoph Gammer
Markus Alfreider
Daniel Kiener
Crack resistance of α2|γ and γ|γ interfaces within a TiAl alloy determined by in situ nano-fracture experiments
Journal of Materials Research and Technology
Intermetallics
Fracture mechanics
TiAl
Interfaces
In situ TEM
title Crack resistance of α2|γ and γ|γ interfaces within a TiAl alloy determined by in situ nano-fracture experiments
title_full Crack resistance of α2|γ and γ|γ interfaces within a TiAl alloy determined by in situ nano-fracture experiments
title_fullStr Crack resistance of α2|γ and γ|γ interfaces within a TiAl alloy determined by in situ nano-fracture experiments
title_full_unstemmed Crack resistance of α2|γ and γ|γ interfaces within a TiAl alloy determined by in situ nano-fracture experiments
title_short Crack resistance of α2|γ and γ|γ interfaces within a TiAl alloy determined by in situ nano-fracture experiments
title_sort crack resistance of α2 γ and γ γ interfaces within a tial alloy determined by in situ nano fracture experiments
topic Intermetallics
Fracture mechanics
TiAl
Interfaces
In situ TEM
url http://www.sciencedirect.com/science/article/pii/S2238785425017053
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AT markusalfreider crackresistanceofa2gandgginterfaceswithinatialalloydeterminedbyinsitunanofractureexperiments
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