| About this Abstract |
| Meeting |
2024 TMS Annual Meeting & Exhibition
|
| Symposium
|
Phase Transformations and Microstructural Evolution
|
| Presentation Title |
Phase Transformation Pathways in B2/bcc Refractory HEAs |
| Author(s) |
Zachary T. Kloenne, Gopal B. Viswanathan, Brian A. Welk, Shalini Roy Koneru, Kamalnath Kadirvel, Yunzhi Wang, Hamish L. Fraser |
| On-Site Speaker (Planned) |
Zachary T. Kloenne |
| Abstract Scope |
The newly developed refractory-HEAs have garnered much attention to fill the “very high temperature” application space. Interestingly, the AlMo0.5NbTa0.5Zr alloy displayed an “inverted” superalloy-like microstructure, i.e. a continuous B2 matrix with bcc precipitates, after slowly cooling from 1400C. The phase transformation pathway (PTP) was determined, through phase-field modeling, to be congruent ordering of bcc into B2, followed by spinodal decomposition into two unique B2 phases, with one of them congruently disordering into bcc. The microstructure was determined stable at 1000C, though coarsening along the [100] directions of the bcc precipitates occurred, resulting in a loss of coherency and an altered B2/bcc interface structure, studied through HRSTEM and dichromatic construction. The “inverted” superalloy-like microstructure in a variant alloy was also achieved, though, in this alloy the B2 phase formed after quenching from high temperature, suggesting a different PTP. This was studied through a combination of advanced electron microscopy and phase-field modeling. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Phase Transformations, High-Entropy Alloys, Mechanical Properties |