Creep Damage Development in Structural Ceramics

Creep rupture of structural ceramics occurs by either the nucleation, growth, and coalescence of grain‐boundary cavities throughout the material or the growth of a dominant flaw. Recent experimental results obtained with small‐angle neutron scattering (SANS) and stereoimaging strain analysis are reviewed and used to answer a number of critical questions pertaining to both damage mechanisms. The nucleation and growth processes of grain‐boundary cavities are examined using the SANS results and pertinent results from other studies. The stochastic nature of cavitation is demonstrated and discussed. Creep‐crack growth is described as either a direct mass transport process or a damage zone growth process. New stereoimaging strain results pertinent to the damage zone growth process are presented and used to elucidate the crack growth process and the growth threshold.