Nucleation of Cavities During Creep of Liquid‐Phase‐Sintered Materials

The nucleation of cavities in the two‐grain channels and three‐grain pockets of liquid‐phase‐sintered ceramics was studied. A thermodynamic approach is used to derive regions of existence for cavities of various morphologies (i.e., spherical, oblate, or prolate) as a function of the nucleating stress and the site dimensions. Classical nucleation theory is also used to predict the nucleation rates for these cavities. Rate restrictions exert a further limitation on the existence of cavities. These considerations suggest that experimentally observed nucleation rates are probably associated with transient stress concentrations, e.g., owing to grain‐boundary sliding.