Cavitation damage during high temperature tensile deformation in fine-grained alumina doped with magnesia or zirconia

For a constant initial grain size of 1.0 μm, damage accumulation proceeds more slowly in a 10-vol%-ZrO₂-doped alumina than in a 0.2-wt%-MgO-doped alumina at 1723 K, at an initial strain rate of 1.7 × 10^-4 s^-1, irrespective of higher tensile flow stress in the former than in the latter. The slower damage accumulation in the ZrO₂-doped material can be attributed to the delay both in the formation of cavities larger than the initial grain size and in their growth. The obtained data indicate that the rate of damage accumulation correlates closely to the tensile ductility which is higher in the ZrO₂-doped material than in the MgO-doped one under the present tensile conditions.