On Crack Arrest in Ceramic / Metal Assemblies

Brittle parts of ceramic/metal assemblies are subjected to a residual stress field generated by the fabrication. During that process, cracks are initiated and the key question is whether they propagate through the whole brittle part. The use of classical probabilistic fracture models applied to the ceramic (i.e., based on a weakest link hypothesis), allow one to conclude that cracks are likely to initiate after the manufacturing process. Consequently, a crack arrest model is proposed, based on a random toughness distribution. Applied to microhardness experiments, the statistical parameters are identified, and the predictive capacity of the model is analyzed. The model is then used to study the reliability of ceramic/metal assemblies during the fabrication stage.