| About this Abstract |
| Meeting |
2023 TMS Annual Meeting & Exhibition
|
| Symposium
|
Advances in Multi-Principal Element Alloys II
|
| Presentation Title |
Synergistic Discontinuous Reactions Leading to Nano-lamellar Hierarchical Microstructures in High Entropy Alloys |
| Author(s) |
Sriswaroop Dasari, Abhishek Sharma, Rajarshi Banerjee |
| On-Site Speaker (Planned) |
Rajarshi Banerjee |
| Abstract Scope |
High entropy alloys (HEAs) often exhibit a wide range of interaction energies (ordering and clustering) due to the presence of multiple principal elements. The local interactions consequently lead to novel phase transformation pathways, typically not observed in conventional alloys. The current study reports a novel hierarchical nano-lamellar microstructure in Al0.3TixCoFeNi type HEAs. While the parent high-temperature phase is FCC in these alloys, isothermal annealing at 600°C leads to a complex microstructure, resulting from synergistic discontinuous reactions i.e., FCC to BCC+B2 (eutectoid) and FCC to FCC+L12 (discontinuous precipitation). These reactions aid each other in forming a hierarchical pearlite-like lamellar microstructure with 50-100 nm thick, alternating FCC+L12 / BCC+B2 lamellae. The relatively sluggish discontinuous reactions emanate from recrystallized FCC grain boundaries, eventually consuming the entire parent grain. This nano-lamellar microstructure in Al0.3CoFeNi exhibits tensile yield stress of 1074 MPa and elongation nearing 10%. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
High-Entropy Alloys, Phase Transformations, Characterization |