Fractographic failure analysis of brittle materials

The fracture characteristics of two groups of brittle materials (structural ceramics and silicide based materials) produced by PM technology and developed for high-temperature applications are reviewed from the viewpoint of fractography. The main observation techniques and fracture-mechanical relations are summarised. The relationship between strength, fracture origins, defects and the relationship between fracture toughness and fracture micromechanisms and microstructure are described. The fractographic appearance of the high-temperature crack growth and creep failure is characterised. The possibilities for improving the fracture toughness and high-temperature properties are discussed.