A review of Al2O3-based eutectic ceramics for high-temperature structural materials

Al₂O₃-based eutectic ceramics are considered as promising candidates for ultra-high-temperature structural materials due to their exceptional thermal stability and mechanical properties. Nonetheless, several challenges must be overcome before they can be widely used. This paper reviews in detail the tailoring of microstructure from the aspect of process parameters, the updated knowledge gained in microstructure (crystallographic orientation, high-resolution interfacial structures) and the latest means of optimizing eutectic microstructure (seed-induced method, introducing low-energy grain boundaries and high-entropy phase). Additionally, the paper explores future techniques for the fabrication of bulk ceramic materials and effective toughening approaches. This review highlights the achievements made especially in the last 15 years, current limitations in Al₂O₃-based eutectic ceramics, and offers comprehensive insights and strategic guidance for further mechanical breakthroughs.