About this Abstract |
| Meeting |
2026 TMS Annual Meeting & Exhibition
|
| Symposium
|
Advances in Multi-Principal Element Alloys V: Mechanical Behavior
|
| Presentation Title |
Ductile-Brittle Transitions in bcc Refractory High-Entropy Alloys |
| Author(s) |
David Cook, Xiaoyu Chen, Michael O'Leary, Satish Rao, Wenqing Wang, Calvin Belcher, Madelyn Payne, Pedro Borges, Arun Devaraj, Mark Asta, Enrique Lavernia, Diran Apelian, Andrew Minor, Dong Liu, Punit Kumar, Robert Ritchie |
| On-Site Speaker (Planned) |
David Cook |
| Abstract Scope |
Body-centered cubic (bcc) metals and alloys possess a ductile-to-brittle transition temperature (DBTT) below which they are brittle, severely restricting their operating conditions. Traditional strategies to suppress the DBTT involve careful interstitial and substitutional alloying to directly facilitate dislocation glide. Here, we assess the DBTT of NbMoTaW- and NbTaTiHf-based refractory high-entropy alloys. We find that these materials display starkly different behavior: whereas NbMoTaW is brittle up to 1473 K, NbTaTiHf is ductile and fracture resistant down to 20 K. The mechanical behavior of the latter system arises from an unusual sequence of deformation mechanisms that is sensitive to the stress-state but insensitive to temperature. Consequently, this sequence prevents the strength from rising with decreasing temperature and inhibits a strength-mediated constriction of the plastic zone that leaves the toughness high and inhibits the DBTT. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
High-Entropy Alloys, High-Temperature Materials, Characterization |