Crystallographic correspondences and variant selection in zirconia-based shape memory ceramics: Insights from EBSD mapping

Previous studies of the martensitic transformation in zirconia ceramics have suggested a preference for specific lattice correspondences based on lattice invariant shear minimization. However, these conclusions have largely been drawn from limited datasets, primarily obtained via transmission electron microscopy. In this work, we employ advanced Electron Backscatter Diffraction (EBSD) methods to statistically analyze the distribution of martensite variants in ZrO₂-CeO₂ alloys. By leveraging novel techniques that resolve the long-standing pseudosymmetry problem in tetragonal zirconia, we demonstrate the simultaneous presence of all twenty-four possible martensitic variants, encompassing three lattice correspondences and two distinct orientation relationships. Our findings challenge the conventional assumption that a single dominant correspondence governs the transformation, and reveal a significant role for self-accommodation mechanisms in variant selection. These results offer new insights into the crystallographic factors governing martensitic transformations in zirconia and open new pathways for microstructural design in shape memory ceramics.