| About this Abstract |
| Meeting |
2025 TMS Annual Meeting & Exhibition
|
| Symposium
|
Advances in Multi-Principal Element Alloys IV: Mechanical Behavior
|
| Presentation Title |
Kink Bands Promote Exceptional Fracture Resistance in a NbTaTiHf Refractory High-Entropy Alloy |
| Author(s) |
David Cook, Punit Kumar, Madelyn Payne, Calvin Belcher, Pedro Borges, Wenqing Wang, Flynn Walsh, Zehao Li, Arun Devaraj, Mingwei Zhang, Mark Asta, Andrew Minor, Enrique Lavernia, Diran Apelian, Robert Ritchie |
| On-Site Speaker (Planned) |
David Cook |
| Abstract Scope |
Body-centered cubic refractory high-entropy alloys (RHEAs) represent a novel design space for high-temperature structural materials. Unfortunately, these materials inhabit the two extremes of the strength-toughness trade-off. While the group V-VI alloys have high compressive strengths at high-temperatures, they suffer from poor tensile ductility and fracture toughness. On the other hand, the group IV-V alloys can exhibit significant tensile plasticity, and even high ambient temperature fracture toughness, but lose strength and ductility at higher temperatures. In this talk, I will discuss the mechanical behavior of a novel NbTaTiHf RHEA. This alloy exhibits significant high-temperature tensile strength retention, and extraordinary fracture toughness characterized by rising R-curve behavior from 77-1473 K. These remarkable properties are attributed to kink band formation, a deformation mechanism that causes strain softening, which runs counter to long-held notions that fracture toughness of metals is derived from mechanisms that prolong uniform ductility and delay plastic instability through strain hardening. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
High-Temperature Materials, High-Entropy Alloys, Mechanical Properties |