Review of research progress in machining fiber-reinforced ceramic matrix composites

Ceramic matrix composites, particularly fiber-reinforced ceramic matrix composites, have emerged as key structural materials for aerospace propulsion systems, energy equipment and other extreme high-temperature environments due to their exceptional specific strength, thermal stability, oxidation resistance and damage tolerance. Among them, Cf/SiC composites are considered one of the most promising candidates for next-generation high-temperature components. Nevertheless, the heterogeneous structure, high hardness and intrinsic brittleness of these materials make their machining extremely challenging, often leading to severe tool wear, unstable material removal behavior and surface or subsurface damage. This review presents a comprehensive and structured overview of the recent progress in machining technologies for fiber-reinforced ceramic matrix composites, with a particular focus on Cf/SiC composites. The preparation routes, microstructural characteristics and machining-related material properties are first summarized to clarify the fundamental origins of machining difficulties. On this basis, conventional machining methods and several advanced hybrid-assisted processes – including laser-assisted machining, electrical discharge machining, abrasive waterjet machining and ultrasonic vibration-assisted machining – are systematically reviewed and critically compared. Their performance is evaluated in terms of material removal mechanisms, cutting force reduction, surface integrity, machining efficiency and process stability. The comparative analysis reveals that hybrid-assisted machining technologies significantly enhance the machinability by modifying the material removal mode and reducing machining-induced damage. In particular, ultrasonic vibration-assisted machining demonstrates notable advantages in suppressing brittle fracture, improving surface quality and extending tool life, making it one of the most promising approaches for precision machining of Cf/SiC composites. Finally, key scientific and technological challenges in the machining of fiber-reinforced ceramic matrix composites are identified, including insufficient understanding of strain-rate-dependent removal mechanisms, tool wear evolution and multi-physics coupling effects during machining. Future research directions are outlined, focusing on mechanism-based process optimization, intelligent machining and real-time monitoring, multi-scale modeling and sustainable manufacturing strategies. This review aims to provide a clearer understanding of current research progress and to serve as a useful reference for the development of high-precision and high-efficiency machining technologies for advanced ceramic matrix composites.