First-principles Investigation of Elastic and Thermophysical Properties of High-entropy Rare-earth Oxide Thermal Barrier Coating Materials

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.* , : 2 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.