Annealing-Driven Recrystallization of Mechanically Deformed Ce-Doped ZrO2 Ceramics

During the annealing, recrystallization processes in ceramics can occur, manifested in the formation of new grains, grain-boundary migration, and grain coarsening. It was expected that recrystallization in mechanically deformed zones, which contain residual stresses and high defect densities, will proceed in a different way compared to the surrounding, relaxed material. Characterizing these spatial variations in defect evolution, phase transformations, and microstructural recovery is essential for predicting performance and avoiding critical structural changes when designing zirconia-based ceramics for high-temperature, load-bearing applications. To study these effects, we used partially stabilized Ce-doped ZrO2 ceramics, fabricated by solid-state synthesis. Phase composition, structural features, and morphology of these ceramics were studied using Raman spectroscopy, XRD and SEM before and after annealing in the mechanically stressed and relaxed regions. In mechanically deformed regions a more pronounced phase transformation from monoclinic to tetragonal was observed compared to relaxed zones. This result indicates that strain can facilitate tetragonal phase formation in zirconia ceramics when the material is subjected to elevated temperatures. Mechanical stresses should be taken into account when fabricating ceramic components, as they can induce phase transformation during heat treatments and change the properties of ceramics significantly.