About this Abstract |
| Meeting |
MS&T26: Materials Science & Technology
|
| Symposium
|
Phase Transformations in Ceramics: Science and Applications
|
| Presentation Title |
Thermodynamic Mapping of High-Entropy-Like Brannerite Wasteform Ceramics Using integrated Calorimetry and Data-Driven Methods |
| Author(s) |
Xiaofeng Guo, Natalie Yaw, Denise Adorno Lopes |
| On-Site Speaker (Planned) |
Xiaofeng Guo |
| Abstract Scope |
Compositionally complex ceramic wasteforms must retain phase stability despite heterogeneous fission-product and actinide inventories in spent nuclear fuel. In brannerite-type titanates, multication mixing can generate competing enthalpic penalties, configurational entropy stabilization, short-range ordering, and charge-compensation effects that control high-temperature stability and phase transformation pathways. Here, we use (U,Ce,Th)Ti2O6 brannerites as a model system to quantify how cation mixing influences the thermodynamics of complex nuclear wasteform ceramics. Phase-pure binary and ternary compositions were synthesized and characterized by diffraction and spectroscopy, with Ce(III)-U(V) charge compensation introducing additional defect-chemical complexity. High temperature oxide melt calorimetry on selected binary compositions provides benchmark mixing energetics, while machine-learning models are being developed to interpolate and predict the thermodynamic landscape of higher-order compositions. This integrated calorimetry-ML workflow enables targeted mapping of phase stability in high-entropy-like ceramic wasteforms and provides a pathway for designing transformation-resistant materials for realistic spent-fuel immobilization. |