Strain evolution of highly asymmetric polycrystalline ferroelectric ceramics via a self-consistent model and in situ X-ray diffraction

Strain and texture evolution (domain switching) of polycrystalline, ferroelectric BaTiO₃ was investigated in four-point bending geometry. Lattice strains were measured by in situ synchrotron X-ray diffraction to address problems related to modeling the constitutive behavior of highly asymmetric ferroelectrics. The hkl-dependent strain measured by X-ray diffraction was found to be smaller relative to both bulk strain measured by conventional, contact-based techniques and elastically computed strain, and reasons for this inconsistency are discussed. A self-consistent model with capabilities of quantifying domain switching and estimating hkl-dependent strain is applied to allow a direct comparison with diffraction data.