Microstructure, mechanical properties, and reinforcement mechanism of carbide toughened ZrC-based ultra-high temperature ceramics: A review

Ultra-high-temperature ceramics (UHTCs) is a kind of material that is in a rapidly evolving technical field, with a very wide range of applications across the aerospace, defense, energy, and civilian as a result of its excellent physical and chemical properties. Within this family, the ZrC-based composites are the most attractive. ZrC has excellent mechanical and physical properties such as high melting point, excellent fire resistance, high hardness, high elastic modulus, and good electrical conductivity. Moreover, compared with other ultra-high-temperature materials, the price of ZrC is lower, and it is a potential non-oxide high-temperature structural material. However, problems pertaining to sintering and moderate fracture toughness have limited its widespread applications. Second-phase toughening is considered to be a promising reinforcement method for ceramic materials. This paper comprehensively reviews the various routes/techniques, including the advanced ones, as adopted for the synthesis and densification of the ZrC-based composites. The research status of ZrC-based composites toughened by particles, fibers, flake graphene, and layered structure is introduced, and the toughening mechanism of ZrC-based composites is summarized. Some of the existing and futuristic applications of ZrC-based composites have also been discussed. Finally, the existing problems and future development direction of ZrC-based composites are also pointed out.