Fracture Behavior of Cyclically Loaded PZT

Abstract

The fracture behavior of PZT specimens driven at their resonant frequency by the application of an ac voltage was investigated and compared with fracture behavior of monotonically loaded PZT. Microcracking was observed in the cyclically loaded specimens; above 150"C, the microcracks were dispersed in small clusters, while at T 5 86"C, microcracks were generated in a densely populated region near the failure site (indentation). Macrocrack growth also demonstrated a temperature dependence, with crack growth occurring at T > 150°C but not at T 5 86°C.

In situ Transmission Electron Microscopy Studies of Electric-field-induced Phenomena in Ferroelectrics

“…[26][27][28][29] Under this assumption, the grain boundary cavitation process found in this in situ TEM study is unusual because it took place at room temperature where the grain boundary phase is expected to behave in a highly brittle manner under mechanical stresses. In fact, the cavitation of the glassy phase suggests that local melting of the grain boundary phase may have taken place during electrical cycling.…”

“…One form of such failures is the grain boundary cracking in polycrystalline materials after they are subjected to extended cycling of bipolar electric fields. [26][27][28][29] It in interesting to notice that grain boundaries in these ceramics are not mechanically weak, and transgranular fracture features are typically observed under mechanical loadings.…”

“…21,22 However, when driven hard with bipolar electric fields for extended cycles, ferroelectric materials may lose their physical integrity due to grain boundary cracking. [26][27][28][29] Our studies with the unique electric field in situ TEM technique, for the first time, directly visualized the dynamic process of the polarization switching of nanometer-sized domains and the cavitation of grain boundaries in ferroelectric ceramics, the fracture of domain walls in ferroelectric single crystals, and the evolution of incommensurate modulations in antiferroelectric ceramics.…”

Fabrication and mechanical reinforcement of piezoelectric nanocomposites with ZrO2 nanoparticles embedded in situ

“…low bend strength and low fracture toughness. Great strength and fracture toughness are required in piezoelectric ceramics intended for high-frequency and highpower applications, and for situations where complex mechanical processing is required [1,2]. Therefore, increasing attention has been focused on understanding and improving the mechanical properties of PZT piezoelectric ceramics.…”

Fatigue crack propagation in a piezoelectric ceramic strip subjected to mode III loading

“…Mechanical failure in cyclically loaded piezoelectric ceramics is a combined effect of environmentally enhanced failure and cyclic fatigue [1]. Recently, the fracture behavior of piezoelectric ceramics have been investigated by White et al [2] under both cyclic and monotonic loading. Extensive studies of the fatigue behavior of piezoelectric ceramics have also been reported by Jiang et al [3], and Cao and Evans [4].…”