Effects of an applied electric field on the modulus of rupture of poled lead zirconate titanate ceramics

The effects of applied dc electric fields of ±10 kV/cm on the modulus of rupture of poled PZT-841 ceramics were studied using three-point bending tests. At each level of the applied electric field, 54 or 55 samples were tested and the data were statistically analyzed. The results showed that the measured moduli of rupture followed a Weibull distribution with a Weibull modulus of 10.6 when no electric field was applied. When the applied electric field was either parallel or antiparallel to the poling direction, the distribution of the modulus of rupture revealed two peaks and was fitted by a two-peak Weibull distribution. One peak occurred at about 95 MPa, approximately the same as that without the presence of the applied electric field, while the other peak occurred around 50 MPa under either a positive or a negative electric field. Obviously, either a positive or a negative electric field assisted the applied mechanical loading to fracture the samples.