| About this Abstract |
| Meeting |
2025 TMS Annual Meeting & Exhibition
|
| Symposium
|
Advances in Multi-Principal Element Alloys IV: Mechanical Behavior
|
| Presentation Title |
Fracture Resistance of Refractory High-Entropy Alloys |
| Author(s) |
Punit Kumar, David H. Cook, Madelyn Payne, Wenqing Wang, Pedro Borges, Mingwei Zhang, Li Yi, Andrew M. Minor, Mark Asta, Robert Ritchie |
| On-Site Speaker (Planned) |
Punit Kumar |
| Abstract Scope |
The fracture resistance of two single-phase bcc refractory high entropy alloys, NbMoTaW and NbTaTiHf, was examined at ambient (RT) to 1200 °C. The fracture toughness of NbMoTaW is strongly dependent on the temperature and the microstructure because the fracture mechanisms transition from transgranular cleavage at RT to a complete intergranular fracture at 1200 °C. Due to extrinsic toughening, the equiaxed microstructure at higher temperatures shows KIc of ⁓10.3 MPa√m; although extremely low, it is ⁓3 times higher than that of columnar microstructures. In contrast, the NbTaTiHf shows remarkable fracture toughness (~15-25 times higher than NbMoTaW) at all temperatures, including KIc of ⁓86 MPa√m at cryogenic temperatures (-196 °C). The remarkable fracture resistance of NbTaTiHf is attributed to the formation of kink bands, i.e., during deformation, the crystal rotates to accommodate strain. This presentation will discuss the origin of such contrasting fracture resistance of the refractory high entropy alloys. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
High-Entropy Alloys, High-Temperature Materials, Mechanical Properties |