Electric field-induced antiferroelectric-to-ferroelectric phase transformation forms the physics basis for the applications of the PbZrO3-based antiferroelectric ceramics. The primary objective was to gain a better understanding of the phase transitions in between ferroelectric and antiferroelectric states. A secondary goal was to verify certain feasible applications by taking advantage of the phase transitions. In-situ techniques were extensively used including in-situ TEM and in-situ Raman microscopy.;Electric field in situ TEM technique was used in the study of the electric field induced antiferroelectric to ferroelectric phase transformation in PbZrO3-PbTiO3-PbSnO3 (PZST) ceramics. Our TEM study indicates that the incommensurate modulation in the modified perovskite antiferroelectrics we studied exists in the form of a transverse Pb-cation displacement wave. The observed incommensurate modulation at large scale is suggested to be a mixture of commensurate modulations at local scale. The modulations were found to disappear at a field level close to the critical field for the antiferroelectric-to-ferroelectric transformation.;Raman peaks that represent ferroelectric and antiferroelectric in PZST 43/y/2 ceramics were identified in order for subsequent monitoring of the phase transitions. Temperature and thermal history dependence of the phase transitions was directly observed with an in situ Raman microscopy technique. Field induced ferroelectric phase stability was analyzed with Raman microscopy. Electric field-induced AFE-FE phase transition was directly observed with an in situ Raman microscopy technique.;With the structural information and the knowledge of the phase transitions in these materials, the electric field-induced fracture behavior was compared in an antiferroelectric and a ferroelectric ceramic with close chemical compositions. The volume expansion during the electric field-induced phase transition leads to the superior fracture resistance in the antiferroelectric ceramic. This volume strain may also toughen the antiferroelectric ceramic under applied mechanical loadings.