Ferroelastic domain switching in lead titanate zirconate ceramics: Temperature dependence and fracture toughness variations

Abstract

Ferroelastic domain switching in electrically-poled lead titanate zirconate (PZT) ceramics were investigated during uni-axial compression up to 400MPa, at a series of temperatures from 25°C to 180°C. It is found that both the stress-induced switchable polarization and switchable strain in the electrically-poled PZT samples decrease steadily with the increasing temperature. By measuring the polarization variations and strain variations of unpoled, prepoled and depoled PZT samples during a full cycle of heating-cooling, it is found that the reduced switchable polarization by stress is caused by the pyroelectric effect and the reduced switchable strain is due to the lattice distortion and thermal shrinkage effect. The fracture toughness of electrically poled and mechanically depoled PZT ceramics were both measured by Vickers indentation and it is found that the fracture toughness anisotropy can even reach 3.63 in the later, significantly larger than that of 2.62 in the former.