About this Abstract |
Meeting |
2025 TMS Annual Meeting & Exhibition
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Symposium
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Advanced Characterization Techniques for Quantifying and Modeling Deformation
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Presentation Title |
Transmission Electron Microscopy Characterization of Deformation Features in Refractory High Entropy Alloys |
Author(s) |
Madelyn Payne, David Cook, Punit Kumar, Pedro Borges, Wenqing Wang, Mingwei Zhang, Robert Ritchie, Mark Asta, Andrew Minor |
On-Site Speaker (Planned) |
Madelyn Payne |
Abstract Scope |
A thermodynamically stable non-equiatomic RHEA with nominal composition Nb0.45Ta0.25Ti0.15Hf0.15 (at%) (NTTH) was tested via compact-tension demonstrating one of the toughest bcc refractory alloys in the literature along with considerable ductility down to liquid nitrogen temperatures. Deformation is accompanied by twinning and the formation of low-angle tilt boundaries known as kink bands. To understand how kinking elevates toughness, we performed several advanced characterization techniques to characterize complex defect structures at the bulk and the crack tip. Our analysis suggests that the toughness of the material is due to coordinated interaction of screw and edge dislocations at the crack tip. In particular, our four-dimensional scanning transmission electron microscopy (4DSTEM) analysis demonstrates edge dislocation slip produces kink bands that prolong non-uniform strain. Through both bulk and microscale experiments we probe the non-conventional role of edge dislocations in the deformation of bcc RHEAs. |
Proceedings Inclusion? |
Planned: |
Keywords |
Characterization, High-Entropy Alloys, Mechanical Properties |