Alumina-based Directionally Solidified Eutectic Ceramics: Microstructure, Control Strategies and Environmental Stability

With rapid advancement of aviation industry, high-temperature structural materials used in aero-engines are encountering increasingly severe service environments and performance challenges.To meet exacting requirements of future technologies, turbine inlet temperature of advanced aero-engines with a thrust-to-weight ratio exceeding 10 is projected to surpass 1500 ℃.Al2O3-based directionally solidified eutectic ceramics are regarded as ideal and key candidate materials for next-generation extreme working conditions, particularly for long-term use in high-temperature oxidative environments, owing to their melting points exceeding 1700 ℃, outstanding high-temperature stability, and inherent oxidation resistance.This paper provides a comprehensive review of microstructural characteristics of Al2O3-第*期 周 翠, 等: 氧化铝基定向凝固共晶陶瓷的组织特性、调控方法及环境稳定性 2 based directionally solidified eutectic ceramics, with particular emphasis on their morphological features, crystallographic relationships and interfacial structures.Subsequently, discussion focuses on strategies for microstructure control, including optimization of processing parameters, optimal selection of eutectic components and implementation of innovative approaches such as high-entropy design.Furthermore, a comprehensive analysis is conducted to evaluate stability of these materials under typical high-temperature service conditions, including thermal exposure, oxidative environments, and chemically corrosive media, with particular emphasis on their chemical stability characteristics.Based on this comprehensive review, key scientific issues and core technical challenges in current research are identified.Future research directions are also proposed to establish a theoretical foundation and provide technical guidance for engineering application of these materials in advanced aero-engine systems.