Stress-Induced Transformation and Plastic Deformation for Y2O3-Containing Tetragonal Zirconia Polycrystals

Yttria-containing tetragonal zirconia polycrystals with low thermal stability showed plastic deformation with a maximum bending strain of 0.8% due to the stress-induced tetragonal to monoclinic transformation. The strain rate depended on applied stress and temperature. The temperature at which the transformation rate is maximum increases with increasing applied stress. Changes in microstructure and crystallographic structure after plastic deformation were examined by transmission electron microscopy and X-ray analyses. The mechanism of plastic deformation is discussed in relation to the tetragonal to monoclinic transformation.