Mechanical Behavior of Alumina Toughened Zirconia Nanocomposites with Different Alumina Additions

ZrO₂ and Al₂O₃ are monolithic ceramics used today in a wide variety of structural components. However, both materials present important drawbacks for some specific applications. In the case of Al₂O₃, its moderate strength (500 MPa) and toughness (4 MPa.√m) makes it unsuitable for high loading conditions. On the other hand, ZrO₂ presents higher strength and toughness values (900 MPa and 6 MPa.√m) than Al₂O₃ but it is a material limited in its long-term behaviour due to its bad response to hydrothermal ageing and a pronounced tendency for subcritical crack growth. Due to this fact, ceramic nanocomposites made of Al₂O₃ and ZrO₂ (ATZ and ZTA) have been developed in the last years in order to overcome the main drawbacks of the monolithic materials as they can combine the properties of both, strong and tough materials, simultaneously, with null ageing and even higher biocompatibility. In this work, several amounts of Al₂O₃ disperse phase (15, 35 and 50 vol %) were added to one ZrO₂ matrix (CeO2 - 10 mol %) in order to see their effect on the mechanical properties, subcritical crack propagation and long-term reliability.