Crystallographic study of the isothermal and athermal martensites of yttria-doped zirconia

Morphology was studied on martensite produced either isothermally at an intermediate temperature or athermally by subzero cooling of coarse-grained zirconia specimens containing 1.9 mol% yttria. The isothermal martensite exhibited well defined thin plates, while athermal martensites formed both in lens and pyramid shapes. The thin-plate and lens-shaped martensites had habit planes near {1 0 3}c in agreement with phenomenological theory, while the pyramidal shape appears to be a strain accommodation structure consisting of four variants.