Abstract:

Continuous fiber-reinforced silicon carbide ceramic matrix composites utilized in hot-section components of high thrust-to-weight ratio aero-engines require protection via thermal/environmental barrier coatings (T/EBCs). To develop novel rare-earth oxide thermal barrier coating materials with low thermal conductivity, compatible thermal expansion coefficients, and excellent high-temperature phase stability, introduction of a high-entropy design concept offers a promising approach and opportunity for composition design and performance optimization. Addressing the challenges of structural modeling and property prediction for complex high-entropy ceramic systems, this study firstly introduces a novel high-entropy ceramic modeling strategy based on the special quasi-random structure (SQS) method. This strategy facilitates rapid prediction of complex ceramic properties while maintaining computational accuracy. Subsequently, crystal structures, elastic properties and thermophysical characteristics of four high-entropy rare-earth oxide materials are predicted and compared by integrating first-principles calculations. This research particularly elucidates regulatory effects and atomic-scale origins of different rare-earth compositions and Hf doping on the material’s low thermal conductivity performance. The research results provide scientific insights and fundamental data for theoretical simulation and material selection design of T/EBCs for aero-engine hot-section components.

Key words: high-entropy rare-earth oxide, thermal barrier coating, first-principles, elastic property, thermophysical property