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 BaTiO 3 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.