Fatigue behavior of ferroelectric ceramics under mechanically–electrically coupled cyclic loads

The fatigue behavior of commercial ferroelectric ceramics PZT-5 was studied by carrying out four-point bending experiments for the poled and unpoled samples. Two types of mechanical loads (constant and cyclic) coupled with a cyclic electrical field were applied. It was observed that under the same cyclic electrical field the fatigue life of the PZT ceramics significantly reduced as the applied mechanical loads (either constant or cyclic) became larger. When coupled with the same electric field, the application of constant forces lowered the fatigue life of the poled samples more significantly than that of the unpoled samples, while the application of mechanically cyclic load remarkably decreased the fatigue life of the unpoled samples.