In situ TEM observation of crack propagation in LiTaO3 particle toughened Al2O3 ceramics

Direct observation of crack propagation in LiTaO3/Al2O3 composite ceramics was carried out using in situ transmission electron microscopy (TEM). Domain switching induced by crack propagation, crack deflection and branching at domain boundaries and ripples similar to the contrasts of 180° domains at the microcrack tip inside LiTaO3 grains were detected evidently. Domain switching, crack deflection, branching and energy dissipation resulting from the formation of contrasts similar to the 180° domains at the microcrack tip, were proposed as the toughening mechanisms in LiTaO3/Al2O3 ceramics.