| About this Abstract |
| Meeting |
2023 TMS Annual Meeting & Exhibition
|
| Symposium
|
Advances in Multi-Principal Element Alloys II
|
| Presentation Title |
J-63: Phase Stability in Ti-Zr-Nb Refractory Medium Entropy Alloys from Atomistic Simulations |
| Author(s) |
Sally Issa, Céline Varvenne, Guy Tréglia, Hakim Amara |
| On-Site Speaker (Planned) |
Céline Varvenne |
| Abstract Scope |
Refractory high entropy alloys having a bcc structure are of great interest because of their excellent mechanical properties retained up to elevated temperatures. But their stability needs to be better understood, and ab initio calculations can provide valuable and accurate insights. Selecting the Ti-Zr-Nb system as a model alloy for group IV and V RHEAs, we map phase stability from dilute to high concentration, equiatomic alloys. We consider both ordered and disordered alloys, the latter being generated as special quasi random structures. In particular, the bcc stability zone is identified as rather extended in alloy composition: this is interpreted in terms of electronic effects and local lattice distortions. In mechanically unstable zones, we show that substitutional defects, like vacancies, always act as phase destabilizers towards more compact and possibly more complex crystallographic structures. We discuss important implications for phase transformation mechanisms and for experimentally observed alloy microstructures. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Phase Transformations, High-Entropy Alloys, Modeling and Simulation |