ultra-high temperature oxide eutectic ceramics, high gradient directional solidification, solidified microstructure, performance control, Motor vehicles. Aeronautics. Astronautics, TL1-4050

With the rapid development of aerospace and other high-tech fields, a new generation of high perfor-mance, high efficiency ultrahigh temperature structural materials and their preparation technologies increasingly becomes the focus of the development of aerospace strategy in the world. Ultrahigh temperature alumina based eutectic ceramics have excellent intrinsic oxidation resistance, corrosion resistance, creep resistance, high strength and other excellent properties. Therefore, they have outstanding advantages and great development prospect in extreme environment such as ultrahigh temperature above 1 400℃, water and oxygen corrosion circumstances. In this paper, the current development status has been firstly introduced for the ultrahigh temperature oxide eutectic ceramics prepared by high gradient directional solidification technologies. Then, the formation mechanism and control method of the defects during the high gradient directional solidification process of the alumina based ultrahigh temperature eutectic ceramics have been summarized. Furthermore, the microstructure characteristics and homogenization control methods, crystal orientation and texture control methods, mechanical properties and strengthening-toughening control methods of oxide eutectic ceramics have been reviewed. Finally, the development trend and breakthrough point have been comprehensively prospected for the preparation of oxide eutectic ceramics with high performance and large size by high gradient directional solidification technologies.