Electromechanical fatigue of lead zirconate titanate ceramics

Mechanical fatigue of lead zirconate titanate ceramics when both an ac electric field and mechanical stress were applied to the specimen was investigated. Fatigue strengths under an ac electric field degraded compared with the fatigue strengths under short-circuit conditions while the slope of the S-N curve was the same as that under the short-circuit condition. The reason for the degradation of fatigue strength under an ac electric field is considered to be the microscopic internal stress caused by the electric-field-induced strain. Degradation of fatigue strengths under an ac electric field became larger when the electric field became bipolar even though the amplitude of the field was the same. The reason for the dependence of fatigue strength under an ac electric field on the applied field polarity is considered that the internal stress became large when the ac electric field became bipolar.