Indentation damage zone in calcium and lead titanate ceramics

Indentation cracks are driven to their equilibrium length by residual stresses produced by the plastic zone beneath the indenter. In the present study, the shape and size of this zone for several lead titanate based materials were investigated. These materials have a range of tetragonal distortions, or c/a ratios. For isotropic unpoled samples the size of the plastic zone can be predicted by elasloplastic theory. The shape of tile plastic zone for poled materials is slightly elliptical with the long and short axes perpendicular and parallel to the poling direction respectively. BCT/363