Stress and strain mapping of micro-domain bundles in barium titanate using electron backscatter diffraction

Published

August 1, 2017

Author(s)

Jane A. Howell, Mark D. Vaudin, Lawrence Henry Friedman, Robert F. Cook

Abstract

Cross-correlation of electron backscatter diffraction patterns has been used to generate stress and strain maps of a single crystal of tetragonal barium titanate (BaTiO3) containing bundles of small, (0.2 to 5) m, a- and c-domains separated by 90 domain boundaries. The strains peaked at the domain boundaries, and approximately equal, but opposite, values were observed in the a- and c-domains; the peak strain magnitudes were slighly less than half the tetragonal distortion of BaTiO3, about 0.004, consistent with a tendency to a cubic structure at domain boundaries. The strain state was dominated by two normal strains: in-plane, perpendicular to domain wall intersections with the surface, and out-of-plane, perpendicular to surface. In distinction to larger, lamellar domains, significant shear strains were also observed. Stress maps were constructed from strain maps using a method that does not require zero stress at reference locations. Peak in-plane normal stresses of approximately 700 MPa were observed. The variation of the stress component parallel to the domain walls was used to determine numerically a microstructurally-based stress intensity factor for crack propagation perpendicular to the domain walls. The conditions for stable microcrack formation in the microstructral stress field and unstable crack propagation under the action of a superposed applied stress were considered in the context of multi-layer ceramic capacitor reliability.

Citation

Journal of Materials Science

Pub Type

Journals

Keywords

electron backscatter diffraction, barium titanate, strain, domain, microdomain, single crystal

Citation

Howell, J. , Vaudin, M. , Friedman, L. and Cook, R. (2017), Stress and strain mapping of micro-domain bundles in barium titanate using electron backscatter diffraction, Journal of Materials Science (Accessed April 27, 2024)