Fatigue behavior of Al2O3-based composite with BaTiO3 piezoelectric phase

Fatigue behavior of Al2O3-based composite with BaTiO3 piezoelectric phase was studied by carrying out four-point bending fatigue tests for the poled and unpoled composites, which was compared to that of monolithic Al2O3. Tests were conducted under load ratio of R = 0.1 at frequency of 20 Hz with sinusoidal waveform. The present composites exhibited high fatigue resistance compared to monolithic Al2O3. From the detailed observations, it was found that the improvement of fatigue strength was mainly due to stress-induced domain switching. The relationship between da/dN and Kmax was evaluated by conducting fatigue crack growth tests. The threshold stress intensity factors for unpoled and poled composites were higher than that of monolithic Al2O3.