Abstract
Grain boundary sliding during superplastic deformation has been investigated for fine-grained Al2O3-20%ZrO2(3 mol%Y2O3 doped ZrO2) ceramics prepared with no additive in order to estimate the grain boundary sliding contribution to superplastic deformation for ceramic materials. Large strains are obtained by compression tests at the temperature of 1400 and 1500°C. Grain boundary sliding is clearly found to take place during the superplastic deformation. The intragranular strain contribution to the total strain was estimated from the aspect ratio of the grains after deformation. The grain boundary sliding was measured by an imaginary scratch line method and a stereographic analysis method. The grain boundary sliding contribution to the total strain can be estimated from the results of the stereographic analysis method, and multiplication by a calibration factor which compensates for the difference between grain boundary sliding at the surface and at the interior of the specimen. The contribution of the Al2O3-20%ZrO2 ceramics are estimated to be about 40∼60%, which increases gradually with strain rate.
