Single Crystal PMN-PT Electric Fatigue and Fracture Behavior

Piezoelectric single crystals are being incorporated into many new devices because of the superior properties they exhibit. Not much attention has been paid to the mechanical robustness of these materials. In this work the fracture and fatigue behavior of Pb(Mg_1/3Nb_2/3)O₃−29 mol% PbTiO₃ (PMN-29PT) is studied. Vickers indentation result show that the K_IC of this material is 0.3 MPa m^1/2. Intentional defects from the indentation show that the <100> direction is the weakest direction and that electrical fatigue is fastest in the <100> direction. By looking at the hysteresis behavior of this material before and after the fatigue runs, the material ages over time.