| Abstract Scope |
Although zirconia-based materials were known to exhibit shape-memory and superelastic effects more than 30 years ago, successful application of these phenomena was impeded due to martensitic transformation-induced volume changes that result in fracture. Studies in the last decade, however, demonstrated that single- or oligocrystalline micropillars, loose particles, and nanofibers can accommodate the volume change of the tetragonal-to-monoclinic transformation, and thus avoid fracture. Inspired by these studies, we developed a freeze-casting method to produce a porous zirconia-based ceramic which combines oligocrystalline pore walls in a honeycomb-like bulk structure, thereby averting transformation-generated fracture. Composition control is afforded through a sol-gel synthesis of CeO<sub>2</sub>-ZrO<sub>2</sub> which allows for uniform distribution of ceria throughout the zirconia. Furthermore, the ceria content can be varied to explore both superelastic and shape-memory behaviors. The martensitic transformation is tracked during compression testing and by Raman spectroscopy and X-ray diffraction. |