Cavitation failure in a superplastic alumina with zirconia-particle dispersion

High temperature tensile in a fine-grained alumina with zirconia particle dispersion is found to relate closely to the separation distance among micrometer-sized cavities growing from preexistent defects and from newly formed ones during deformation. As the separation distance is decreased to a certain level with an increase in both density and size of such cavities, extensive cavity interlinkage starts to cause microcracking, and the microcracking leads to the occurrence of macroscopic cracks propagating in a direction perpendicular to the tensile axis toward the final failure. The dependence of the onset strain of microcracking on temperature and grain size is also found to relate closely to the dependence of cavity formation and growth rates on these factors.