| About this Abstract |
| Meeting |
3rd World Congress on High Entropy Alloys (HEA 2023)
|
| Symposium
|
HEA 2023
|
| Presentation Title |
B2 Phase in Refractory High Entropy Alloys: Macroscopic B2 Ordering Signal May Not Really Represent B2 Stability |
| Author(s) |
An-Chen Fan, Yun-Syuan Chen, Chong-Chi Chi, Chih-Hao Hsu, Kai-Cheng Yang, Daniel Miracle, Ming-Yen Lu, Ming-Hung Tsai |
| On-Site Speaker (Planned) |
An-Chen Fan |
| Abstract Scope |
Refractory high entropy alloys (RHEAs) with superalloy-like BCC+B2 microstructure, namely refractory high-entropy superalloys (RHESAs), have demonstrated superior resistance to thermal softening compared to single-phased BCC RHEAs, resulting in enhanced strength at elevated temperatures. However, the understanding of the equilibrium condition of the B2 phase in RHEAs remains unclear. In this study, three alloys from the Al-Nb-Ta-Ti-Zr system were selected to investigate the phase constituents, phase composition, and microstructure at different temperatures, as they potentially contain the B2 phase. Surprisingly, nanoscale interconnected structures consisting of BCC+B2 phases were observed in all the macroscopic "B2" phases in these alloys. Detailed analysis of these structures suggests that the B2 phases within the interconnected structure are formed through spinodal decomposition during the quenching process, indicating the absence of an equilibrium B2 phase above 700°C in the three alloys. The challenges associated with accurately identifying the equilibrium B2 phase in these materials are also discussed. |
| Proceedings Inclusion? |
Planned: Metallurgical and Materials Transactions |