Effects of electric field and biaxial flexure on the failure of poled lead zirconate titanate

• Published in: IEEE transactions on ultrasonics, ferroelectrics, and frequency control ferroelectrics, and frequency control, 2008-12, Vol.55 (12), p.2559-2570
• Main Authors: Hong Wang, Wereszczak, A.A.
• Format: Article
• Language: English
• Subjects: Acoustics; Actuators; Algorithms; Ceramics; Ceramics - chemistry; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Demand; Design optimization; Domain effects, magnetization curves, and hysteresis; Domain walls and domain structure; Electric fields; Electric potential; Electrochemistry - instrumentation; Equipment Failure Analysis; Exact sciences and technology; Failure; Failure analysis; Fundamental areas of phenomenology (including applications); General equipment and techniques; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Internal stresses; Lead - chemistry; Lead zirconate titanates; Magnetic properties and materials; Materials testing; Mechanics; Microscopy, Electron, Scanning; Modulus of rupture in bending; Nonhomogeneous media; Physics; Piezoelectric materials; Strength; Stress, Mechanical; Studies; Surface cracks; Titanium - chemistry; Titanium compounds; Transducers; Transduction; acoustical devices for the generation and reproduction of sound; Ultrasonics, quantum acoustics, and physical effects of sound; Zirconium - chemistry
• ISSN: 0885-3010; 1525-8955
• DOI: 10.1109/TUFFC.2008.972

Reliable design of lead zirconate titanate (PZT) piezo stack actuators demands that several issues, including electromechanical coupling and ceramic strength-size scaling, be scrutinized. This study addresses those through the use of ball-on-ring (BoR) biaxial flexure strength tests of a PZT piezoelectric material that is concurrently subjected to an electric field. The Weibull strength distributions and fracture surfaces were examined. The mechanical failures were further analyzed in terms of internal stress, energy release rate, and domain-switching toughening. Both the sign and the magnitude of an electric field had a significant effect on the strength of poled PZT within the tested range. A surface flaw type with an average depth of around 18 mum was identified to be the strength limiter and responsible for the failure of the tested PZT under both mechanical and electromechanical loadings. With a value of 0.74 MPamiddotm 1/2 in the absence of electric field, the fracture toughness of the poled PZT was affected by an applied electric field just as the strength was affected. These results and observations have the potential to serve probabilistic reliability analysis and design optimization of multilayer PZT piezo actuators.