Abstract
The basic objective of this study is to establish the material design concepts for the coexistence of good high-temperature mechanical properties and super heat resistance in the systems of ceramic/metal and ceramic/ceramic functionally gradient materials (FGMs). Flexural and fracture toughness tests were conducted on gas-pressure combustion-sintered Cr3C2 ceramic and its composites with Ni and TiC (Cr3C2/Ni, Cr3C2/TiC) in a vacuum environment up to 1200°C using a newly developed materials testing system. Fracture characteristics were investigated on the basis of fracture mechanics and fractography. The toughness of Cr3C2 can be improved by the addition of metallic particles. It is found that the principal mechanism of toughness improvement in these composites (ductile-phase reinforced ceramic matrix composites) is attributable to crack-tip plastic blunting by a ductile metallic phase.
