Superplasticity in zirconia-dispersed alumina prepared by colloidal processing

Substantial superplasticity, where total tensile elongation to failure exceeds 500% at 1773 K, is attained in a zirconia-dispersed alumina by grain size refinement to less than 0.5 mu m through colloidal processing. The material shows gradual strain hardening persisting up to large strains owing to gradual grain growth and damage accumulation. In contrast, the grain size refinement to 0.45 mu m through conventional dry processing is not effective in enhancing tensile ductility. From the microstructural data of these materials, the prerequisites are discussed for obtaining large tensile ductility in zirconia-dispersed alumina.