| About this Abstract |
| Meeting |
2024 TMS Annual Meeting & Exhibition
|
| Symposium
|
Advances in Ceramic Materials and Processing
|
| Presentation Title |
A Combined DFT and NPD Approach to Determine the Phase Boundaries of the ε-phase of Tungsten Boride |
| Author(s) |
Samaneh Sadat Setayandeh, Patrick Burr, Jennifer Stansby, Edward Obbard, Jack Astbury, Kevin Laws, David Miskovic, Chris Wilson, Vanessa Peterson, Sandeep Irukuvarghula, Matt Brand, Sercan Cetinkaya |
| On-Site Speaker (Planned) |
Sercan Cetinkaya |
| Abstract Scope |
The ε-phase of tungsten boride, previously reported as W2B5, is promising for shielding applications in spherical tokamak fusion reactors. However, the lack of consensus regarding its structure and composition has hindered further research. In this study, we utilized density functional theory (DFT) simulations and neutron powder diffraction techniques (NPD) to determine the stable crystal structure and stoichiometry range of ε tungsten borides. Our results indicate that two structures, W2B4-x (x = 0.25-0.5), exhibit thermodynamic stability with space group symmetries P63/mmc and P63/mcm. These candidates contain 6.2-7.8 at. % less boron than the reported W2B5 composition in existing phase diagrams, indicating the need to revisit the existing phase diagram. To confirm our findings, we performed NPD on 11B-enriched arc-melted and crushed samples. Rietveld refinement of the neutron data identified the correct phase boundaries and revealed that the ε-phase is better described as W2B3.60(2) (P63/mcm), aligning with DFT simulations. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Ceramics, Characterization, Computational Materials Science & Engineering |