FERROELASTICITY OF THE DISPLACIVE TETRAGONAL PHASE IN Y2O3 PARTIALLY-STABILIZED ZRO2 (Y-PSZ) SINGLE-CRYSTALS

Ferroelasticity of the tetragonal displacive (t') phase was studied on 4.7 mol% Y2O3 partially stabilized zirconia single crystals. Samples were deformed at 1400 degrees C at constant strain rate to induce the ferroelastic behavior. Domain reorientation due to the applied stress has been studied as a function of the compression axis and aging time at 1600 degrees C. Domain switching was found in the as-received and 2 -h-aged crystals deformed along the [100] direction, in which an excep tional high flow stress was reached (>700 MPa). Transmission electron microscopy observations were performed on deformed and undeformed crys tals to study the microstructural changes associated with the domain s witching. Incremental strain steps on the stress-strain curves and sur face texture on the lateral faces of the deformed samples were correla ted with the microstructural evidence.