Micromechanical study on the morphology of martensite in constrained zirconia

Either pure cooling induced martensitic transformation or pure stress assisted martensitic transformation in constrained zirconia in two materials with homogeneous (PSZ) and heterogeneous (ZTA) elastic and thermal properties is investigated by the finite element method. The morphology of the martensite (number of twin bands, relative thickness) determines the strain energy caused by the transformation which contributes to the mechanical transformation barrier. In the case of small particles the interface energy enters the transformation barrier, whereas for large particles it can be neglected. The thermodynamic existence condition predicts that the martensitic microstructure that is most likely to occur for the selected applied loading stress states is in good agreement with the experimental observations.