A dislocation mechanism of crack nucleation in cubic zirconia single crystals

Abstract

Abstract The dislocation structure around elevated-temperature indentations on {111} planes of 9·4 and 21 mol.% Y2O3 fully stabilized cubic ZrO2, was investigated using selective etching and transmission electron microscopy (TEM). The temperature dependences of the microhardness and the extent of the plastic zone were measured. Different fracture modes were detected in the two materials. Cracking arising from interaction between slip bands was observed in the 21 mol.% Y2O3 material and direct evidence of the formation of Lomer-type dislocation pile-ups leading to crack nucleation was obtained by TEM. The mechanisms of dislocation plasticity and fracture during indentation of cubic zirconia are discussed.