Fracture Mechanics Of Green Products
Published 1993 · Materials Science
Abstract The tensile strength of ceramic green samples (binderless zirconia powder) was investigated within the formalism of linear fracture mechanics. Dry pressed samples were found to obey fairly well the classical laws (Weibull's statistics, the relationship between stress intensity factor and fracture energy). The comparison between the mechanical properties of pressed and cast samples showed that the interparticle forces responsible for the cohesion depend strongly on the shape-forming process. The mechanical interlocking of particle asperities is of primary importance in the strength of pressed samples. Moreover, for a given density the critical defect size is larger in cast than in pressed samples, while the pore size distribution is sharper (which is usually considered as a proof of ‘better’ microstructure). This sheds light on the differences between cracks in granular materials and pore structure.