The Effect of Electric Fields on the Subcritical Crack Propagation in Selected Dielectric Glasses and Ceramics
Abstract
Effects of electrical fields on cracking behavior of ceramics were examined in four different ceramics, namely, glass, magnesium oxide (MgO), lead zirconate titanate (PZT) and lead lanthanum zirconate titanate (PLZT). When the electrical field was non-orthogonal to the crack plane, deflection of microcracks occurred. The deflection angle was as high as 90 degrees from the original crack-plane, depending on the relative orientation of the electrical field to the crack plane. In piezoelectric ceramics, crack growth was observed under both DC and AC electric fields. The crack growth under AC electric fields was a strong function of the mean electrical field. Micromechanisms of cracking were examined by a new in-situ transmission electron microscopy technique, developed for observations of electric-field induced cracking in ferroelectric ceramics. With this technique, cracking of the domain boundary under both static and alternating electric field was directly observed for the first time in PMN-PT crystals and in a commercial EC65 PZT ceramic. Domain alignments and switching were also directly imaged near crack-like flaws.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 14, 2000
- Accession Number
- ADA384779
Entities
People
- Jian-ku Shang
Organizations
- University of Illinois Urbana–Champaign