About this Abstract |
Meeting |
MS&T23: Materials Science & Technology
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Symposium
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High Entropy Materials: Concentrated Solid Solutions, Intermetallics, Ceramics, Functional Materials and Beyond IV
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Presentation Title |
Development of BCC-B2 Microstructure in Nb-Ti-Ru Refractory Superalloys |
Author(s) |
Melanie K. Moczadlo, Eric A. Lass |
On-Site Speaker (Planned) |
Melanie K. Moczadlo |
Abstract Scope |
Body-centered cubic (BCC) refractory-based compositionally complex alloys (R-CCAs) show promise as next generation materials for high-temperature, high-strength applications; and the discovery of two-phase BCC+B2 R-CCAs, analogous to γ-γ’ Ni-based superalloys, has opened the possibility of precipitation strengthened R-CCAs, or refractory superalloys (RSAs). Existing binary phase diagrams combined with thermodynamic calculations suggest that the ternary alloy system Nb-Ti-Ru should exhibit a two-phase BCC+B2 microstructure that is stable to temperatures >1500 ˚C. The present study investigates two such alloys, (Nb3Ti)0.85Ru0.15 and (Nb4Ti)0.85Ru0.15. A stable two-phase microstructure, consisting of Nb-rich BCC and Ti-Ru-rich B2, is observed after annealing at 1300 ˚C for times up to 7 days. The lattice in both alloys is larger than expected, 6-7 %, suggesting an incoherent BCC/B2 interface. However, the partitioning behavior exhibited by the alloys provides insight into the design of new Nb-Ti-Ru and Nb-Ti-Ru-X alloys with low-lattice misfit. |