Pressure induced local phase transformation in nanocrystalline tetragonal zirconia microparticles

Mechanical properties and local martensitic phase transformation of individual nanocrystalline zirconia microspheres were assessed by complementary (in situ) electron microscopy techniques. Particles were deformed by compression in a SEM and the local structure was determined by ex situ SAED of a FIB prepared lamella. The local texture and amount of transformed grains can be explained by a continuum-like behavior modelled by FEM calculations: The phase transformation is found for grains which are preferentially oriented with respect to the deviatoric stresses and show the rotation of the maximum shear stress during the experiment.