Very fine-grained (0·2 μm), dense Y-TZP ceramics have been produced by free sintering at 1150°C. The superplastic deformation of these materials is studied in compression at low temperatures (1100-1300°C). A significant enhancement in initial strain rates was observed compared to a coarser-grained (0·4 μm) commercially available material (Tosoh, Japan). Doping with small amounts of Fe2O3 led to a further enhancement of strain rate. Deformation occurred via interface reaction controlled grain boundary sliding. Prior to deformation a continuous glassy silicate film was observed at the grain boundaries. The applicability of interface reaction controlled solution-precipitation creep models is discussed. The absence of a steady-state during deformation at low stresses is attributed to dewetting of the silicate film.
Boutz, M. M. R., Winnubst, A. J. A., Burggraaf, A. J., Nauer, M., & Carry, C. (1994). Low temperature superplastic flow of yttria stabilized tetragonal zirconia polycrystals. Journal of the European Ceramic Society, 13(2), 103-111. https://doi.org/10.1016/0955-2219(94)90107-4