Mechanical behavior of zirconia/alumina composites

Zirconia/alumina composites were fabricated by hot pressing 10 mol% yttria-stabilized zirconia (10-YSZ) reinforced with 0-30 mol% alumina particulates or platelets. Flexure strength and fracture toughness of both particulate and platelet composites increased with increasing alumina content. For a given alumina content, strength of particulate composites was greater than that of platelet composites; whereas, difference in fracture toughness between the two composite systems was negligible. No difference in elastic modulus and density was observed for a given alumina content between particulate and platelet composites. Thermal cycling up to 10 cycles between 200 and 1000 °C did not show any strength degradation of the 30 mol% platelet composites, indicative of negligible influence of coefficient-of-thermal-expansion mismatch between YSZ and alumina grains.