Cyclic Fatigue Properties of Piezoelectric Ceramics

High-frequency cyclic fatigue properties of lead titanate (PT) and lead zirconate titanate (PZT) were investigated experimentally. No obvious effect of cyclic load was observed on the crack propagation in PT, whereas the stress ratio (R) resulted in different crack propagation behavior in PZT (i.e., R-curve behavior or accelerative effect). In order to express the phenomenon quantitatively, the constants (A and n) in the crack propagation rate equation V=A(KI/KIC)n were determined. When the relation was plotted, ΔA((AC/AS): ratio of constant A under respective static fatigue to cyclic fatigue conditions) proved to be a very effective parameter to express the crack propagation characteristics.