Thermal Shock Resistance of Al2 O3/ZrO2 (Y2O3) Composites

ZrO2 containing 2% (mol fraction) Y2O3 and 3% (mol fraction) Y2O3 were added into Al2O3 matrix, compositing composites with 15% volume fraction of addictives mentioned above. The testing of property and analysis of SEM presented that, after vacuum sintering at 1550 °C, thermal shock resistance of two composites was superior to Al2O3 ceramic. The experiment showed that the properties of Al2O3 composites was higher than Al2O3 ceramic, and Al2O3/ZrO2(3Y) was higher than Al2O3/ZrO2(2Y) in thermal shock resistance. Improvement of thermal shock resistance of composites was attributed to many toughness machanisms of ZrO2(Y2O3). By calculation, the fracture energy of Al2O3, Al2O3/ZrO2 (2Y) and Al2O3/ZrO2(3Y) was 38100.8 and 126.2 J·m−2, respectively. Cracks initiation resistance (Rʹ) of Al2O3/ZrO2(3Y) and Al2O3/ZrO2(2Y) was higher than Al2O3 ceramic by 1.57 and 1.41 time, respectively, and cracks propagation resistance (R″″) was higher than Al2O3 ceramic by 1.46 and 1.38 time, respectively, which was corresponding to the results of residual strength.