Processing‐Dependent Microstructural Factors Affecting Cavitation Damage and Tensile Ductility in a Superplastic Alumina Dispersed with Zirconia

Superplastic tensile ductility in Al 2 O 3 –10 vol% ZrO 2 (3 mol% Y 2 O 3 ) exhibits processing dependence when the grain size is reduced to 0.45 μm for a given relative density of ∼99.5%. The reduced grain size leads to largely enhanced ductility in a material prepared by colloidal processing, but does not in a material prepared by conventional dry processing. This result is explained from cavity‐damage accumulation sensitive to a rather small variation in a few processing‐dependent factors: the numerical densities of residual defects and ZrO 2 particles. The rate of damage accumulation is shown to depend mainly on the former and additionally on the latter.