The fracture of ceramic materials is often preceded by subcritical crack growth originating from flaws or cracks contained in these materials. Subcritical crack growth usually results from a stress-enhanced chemical interaction between the solid and moisture in the environment and has been observed in glasses, porcelains, oxides, silicate minerals and titanates. Since subcritical crack growth precedes catastrophic fracture, a delay to failure is often observed in components subjected to a static load. Subcritical crack growth also leads to a time dependence of the strength, the slower the loading rate, the weaker the material. The science of fracture mechanics provides a logical framework for understanding the effect of subcritical crack growth on structural ceramics and for predicting lifetime.
Encyclopedia of Materials
aluminum oxide, ceramics, crack growth, fracture, glass, lifetime prediction