About this Abstract |
| Meeting |
2026 TMS Annual Meeting & Exhibition
|
| Symposium
|
Refractory Metals 2026 – A Memorial to Todd Leonhardt
|
| Presentation Title |
Fabrication of Dense Bulk Ultrafine-Grained MoW, NbMoW, and NbMoTaW and the Effects of Cobalt Doping on Sintering and Grain Growth |
| Author(s) |
Keyu Cao, Sashank Shivakumar, Jian Luo |
| On-Site Speaker (Planned) |
Keyu Cao |
| Abstract Scope |
In this study, we fabricated a set of ultrafine-grained refractory alloys, MoW, NbMoW, and NbMoTaW, using high-entropy ball milling (HEBM) and spark plasma sintering (SPS), and further examined effects of cobalt (Co) doping. Addition of 2% Co enhanced the sintering and increased the relative densities from ~92-96% to ~96-98% after SPS at 1200 °C. We further conducted grain growth experiments. A continuous Co segregation along the GB was observed. The NbMoTaW + 2 at.% Co specimens showed excellent stability against grain growth, with only moderate grain growth from ~122 nm to ~128 nm after 5 h annealing at 1200 °C. Grain boundary segregation of Co, which was confirmed by STEM-EDS analysis, promoted sintering. Grain boundary segregation of Co likely also suppressed grain growth of NbMoTaW, and the effect is more pronouncing with increasing configurational entropy. Possible effects of high-entropy grain boundaries (HEGBs) [Communications Materials 4:7 (2023)] are inferred and discussed. |
| Proceedings Inclusion? |
Undecided |
| Keywords |
High-Entropy Alloys, High-Temperature Materials, |