Electro-elastic stress analysis for a Zener-Stroh crack at the interface of a piezoelectric material bonding to a metal

Abstract

As a kind of smart material, lead-zirconate-titanate (PZT) ceramics are widely used in microelectromechanical systems (MEMS). Often bonded to the PZT layer, metal electrodes (Cu or Pt) work to supply the voltage across the PZT material and also act as a template to ensure the correct crystallographic alignment of the piezoelectric film at the same time a Zener-Stroh crack can be nucleated at the PZT/metal bimaterial interface when piled-up dislocations along a slip plane in metal material are stopped by the interface that works as an obstacle. In the current research, the interfacial Zener-Stroh crack problem is formulated into a set of singular integral equations with a distributed dislocation technique. The singular integral equations are then solved with a numerical method following their nature of singularities. To tackle the oscillation behaviors near the crack tips, the contact zone model is considered. The stress field, stress and electric displacement intensity factors (SEDIFs), and contact zone lengths are also discussed in the chapter based on the numerical results.