Tetragonal-to-monoclinic phase transformation in CeO2-stabilised zirconia under uniaxial loading

The critical transformation stresses of five 9 mol% Ce-TZP materials with different grain sizes have been investigated in bending. It was found that two different types of phase transformation mechanisms occur in these materials. (a) A homogeneous phase transformation with a transformation strain increasing continuously with increasing applied stress. This transformation type produces the initial deviation from linear–elastic material behaviour in the stress–strain curves. (b) An autocatalytic phase transformation with the autocatalytic formation of transformation bands, leading to a strongly inhomogeneous, localised distribution of the monoclinic phase. Their locations and sizes vary randomly. The formation of the transformation bands has been monitored by acoustic emission recording. The amount of monoclinic phase content has been quantified by X-ray diffractometry and Raman spectroscopy.