Influence of phase constitution on mechanical performance of 12Ce-3Y-ZrO2/2.5 wt pct Al2O3 composites

The phase constitution of a composite consisting of 1.2 at. pct CeO2-3 at. Pct Y2O3-ZrO2/2.5 wt pct Al2O3 (3Y12Ce2.5Al) was determined by thermodynamic calculation. It is a combination of 36.9 at. pct cubic phase and 63.1 at. pct tetragonal phase at 1450 C. Green compacts were fabricated by cold isostatic pressing with powder synthesized by coating technique, and pressureless sintered at 1450 degreesC. The fracture toughness and Vickers hardness, evaluated by the micro-indentation method, are 2.02 MPa(.)m(1/2) and 11.395 GPa, respectively. The addition of 3 at. Pct Y2O3 to 12 at. pct CeO2-ZrO2 ceramic leads to drastically decrease in toughness compared to composites without yttria stabilizer. No monoclinic phase is detected on the surface of all the ground samples. The high content of cubic phase and lack of phase transformation can be attributed to the low toughness based on the thermodynamic: prediction.status: publishe