Microstructure and superplasticity in various zirconia-dispersed aluminas

High-temperature tensile ductility in alumina-based ceramics is usually limited due to dynamic grain growth. In this study, superplasticity in zirconia-dispersed alumina has been achieved by colloidal processing using monoclinic, tetragonal and cubic zirconia powders. The densities and microstructures depend on the zirconia particles used as a second phase. Differences in the static alumina grain growth in various zirconia-dispersed alumina composites were caused by differences in distribution of the zirconia particles. The tensile ductility of these materials was found to depend on the type of zirconia used. Limited superplasticity seems to be caused by the density and dynamic alumina grain growth during deformation.