Stress-induced phase transformation in the vicinity of Vickers indentations in 10mol% CeO2 doped tetragonal ZrO2 polycrystal

The stress-induced martensitic phase transformation from a tetragonal (t) phase to a monoclinic (m) phase in a CeO₂ doped tetragonal polycrystal (Ce-TZP) was investigated from the view pints of characters of lattice correspondences (LCs) between tand m-phases and morphology of m-phase. Electron back scattering diffraction (EBSD) analysis in the vicinity of Vickers indentations in Ce-TZP reveled that there were three LCs, named LCA (type A), LCB (type B) and LCC (type C), where fractions of the three LCs were 12%, 8% and 80%, respectively. Morphology of m-phase showing each of the three LCs were observed by transmission electron microscopy (TEM). A single variant of mphase with lamellar plate-shaped morphology (m-plates) was formed near the Vickers indentations. In contrast, two variants of m-phases with twin relationships (m-twins) were formed far from the Vickers indentations. The infinitesimal-deformation theory was adopted to calculate scalar magnitude of internal stress within the m-plates and m-twins for each type of the LCs. Irrespective of morphology of the m-phase, the internal stress field for type C is a tensile stress field. Regardless of the type of LCs, absolute values of internal stress in the m-plates are higher than those in the mtwins.