Abstract: Continuous fiber-reinforced silicon carbide ceramic matrix composites utlized in hot-section components of high thrust-to-weight ratio aero-engines require protection via thermal/environmental barrier coatings. To develop novel rare-earth oxide thermal barrier coatings materials with low thermal conductivity, compatible thermal expansion coefficients, and excellent high-temperature phase stability, the introduction of the 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 first introduces a novel high-entropy ceramic modeling strategy based on the Special Quasi-random Structure(SQS) method. This strategy facilitates the rapid prediction of complex ceramic properties while maintaining computational accuracy. Subsequently, the crystal structures, elastic properties, and thermophysical characteristics of four high-entropy rare-earth oxide materials are predicted and compared by integrating first-principles calculations. The research particularly aims to elucidate the 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 the theoretical simulation and material selection design of thermal/environmental barrier coatings for aero-engine hot-section components.

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