Effect of the particulate size on mechanical properties of alumina-zirconia composites

摘要

The effect of particulate size of alumina addition on mechanical properties of zirconia containing 3 mol% Y_2O_3 (3Y-TZP) was investigated. Composites containing 15 vol.% Al_2O_3 either as broken or as unbroken platelets ranging from 1 to 11 μm were fabricated by hot isostatic pressing. Additions of Al_2O_3 to YSZ resulted in enhanced fracture toughness with a trend to lower values of K_(1c) with increasing platelet size. Observations of cracks produced by Vickers indentation and in-situ crack propagation studies lead to assume that the addition of Al_2O_3 enlarged the process zone size. The formation of elastic bridges was observed and is believed to be a contribution to the R-curve properties.