Hard lead zirconate titanate (PZT) and PZT/Al2O3 composites were prepared and the alternating electric-field induced crack growth behavior of a precrack above the coercive field was evaluated via optical and scanning electron microscopy. The crack extension in the 1.0 vol% Al2O3 composite was significantly smaller than that in monolithic PZT and the 0.5 vol% Al2O3 composite. Secondary-phase Al2O3 dispersoids were found both at grain boundaries and within grains in the composites. A large number of dispersoids were observed at the grain boundaries in the 1.0 vol% Al2O3 composite. It appears that the Al2O3 dispersoids reinforce the grain boundaries of the PZT matrix as well as act as effective pins against microcrack propagation.