A constrained domain-switching model for polycrystalline ferroelectric ceramics. Part II: Combined switching and application to rhombohedral materials

A combined switching assumption (CSA) is incorporated into the constrained domain-switching model presented in part I to address the nonsymmetric deformations of ferroelectric ceramics under tension and compression. Using the CSA, the domain-switching process in rhombohedral ferroelectric/ferroelastic ceramics is analyzed in detail. The results show that in rhombohedral lead titanate zirconate (PZT) ceramics, most 109 switching can be accomplished with a minor fraction of 71 switching during electric poling, which is quite different from BaTiO3 and tetragonal PZT ceramics in which only a few per cent of 90 switching can occur. Domain switching under combined uniaxial electric and mechanical tension/compression is also studied. Uniaxial tension is found to enhance electric poling while uniaxial compression inhibits it.