Pro- and Subeutectoid Behavior of the Tetragonal Phase in Magnesia-Partially-Stabilized Zirconia

Magnesia-partially-stabilized zirconia (Mg-PSZ) is industrially important because of transformable metastable tetragonal precipitates which interact with and arrest cracks. This work addresses the precipitation of tetragonal phases at one composition, 9.5 mol% MgO, throughout a range of temperatures. High-purity zirconia samples were sintered at 1700°C and rapidly quenched to heat-treatment temperatures ranging from 1600° to 1100°C, then quenched to room temperature. Cooling rates through the tetragonal + MgO and the monoclinic + MgO two-phase regions were found to affect the phase content. The kinetics of nonequilibrium phase transformation for high-purity Mg-PSZ are presented in terms of time-temperature-transformation diagrams.