On structural features responsible for the mechanical properties of ceramics from zirconia partially stabilized with Y3+ and Mg2+ ions

It is shown that Y-PSZ ceramics mainly fracture by an intercrystalline mechanism and the grain size fluctuates from 0.2 to 0.8 μm, whereas Mg-PSZ ceramics mainly fracture by a transcrystalline mechanism and the grain size fluctuates from 30 to 80 μm. The high level of mechanical properties is provided by compressive stresses that appear in the transformation of the β'-phase into the a-phase. In the Y-PSZ ceramics the transformation concerns individual grains, and in the Mg-PSZ ceramics lenticular segregations of the β'-phase are positioned in the γ-phase. The transformation is induced by tensile stresses of the elastic field of a crack, i.e., can be classified as transformation toughening.[PUBLICATION ABSTRACT]