High temperature blocking force measurements of soft lead zirconate titanate

Piezoelectric actuators outperform other technological solutions in the area of high-speed, high-force and high-accuracy displacement, but are only able to generate strains of about 0.2%. The load capability is generally quantified in terms of a blocking force, which is the force sustained under electric field at zero displacement. Stress-strain curves in a temperature regime from room temperature up to 150 0C on electrically loaded soft lead zirconate titanate (PZT) are generated to determine the blocking stress. The ensuing nonlinear behaviour is discussed in terms of ferroelectric and ferroelastic switching and contrasted to idealized linear constitutive behaviour as often assumed by manufacturers. The blocking stress is shown to increase with temperature due to an additional stiffening effect as a function of electric field. The actual mechanical work done is found to be larger than in the idealized case where linear constitutive behaviour is assumed.