Research progress in directionally solidified structure-function integrated alumina based eutectic composite ceramics

The rapid advancement of high-tech technologies such as aerospace， electronic information， and biomedicine has required more demands on the properties of advanced ceramic materials. Single-characteristic structural or functional materials cannot meet the current requirements， so the high-performance composite ceramics with integrated structure and function have become global research objectives. Directionally solidified oxide eutectic composite ceramics are a class of structural and functional integrated composite materials developed in recent years for long-term service in ultra-high temperature oxidizing environments. They have characteristics such as high melting point， low density， excellent high-temperature strength， and high-temperature creep performance， while also possessing functional properties such as optics， electromagnetism， and biology. The latest development of directionally solidified structure-function integrated eutectic ceramics was reviewed， specifically focusing on Al2O3-based eutectic ceramic systems. The various preparation methods， technical principles， and growth characteristics associated with directionally solidified eutectic ceramics were summarized. Furthermore， the solidification microstructure and structural characteristics observed in a series of Al2O3-based eutectic ceramics were elaborated. The mechanical， optical， magnetic， and biological properties of composite ceramics and their influencing factors were analyzed， and their characteristics， advantages， and application scope were introduced. Finally， the review summarizes the challenges and key bottlenecks faced by directionally solidified eutectic composite ceramics in engineering applications and proposes the main directions for the development of eutectic composite ceramic materials in terms of forming technology innovation， comprehensive performance improvement， and the development of new systems.