Mechanical properties and microstructure for 3 mol% yttria doped zirconia/silicon carbide nanocomposites

Abstract

3 Mol% yttria stabilized tetragonal zirconia polycrystalline (3Y-TZP) is well known as a transformation toughening material with excellent mechanical properties at ambient temperature. However, the properties of 3Y-TZP drop down with increasing temperature. In this study, nanocomposite techniques were applied in order to improve mechanical properties of 3Y-TZP. 3Y-TZP/SiC nanocomposites were fabricated by hot-pressing, and effects of SiC particles on microstructure, transformation from tetragonal zirconia (t-ZrO2) to monoclinic ZrO2 (m-ZrO2) and its mechanical properties were investigated. Fracture toughness of the nanocomposite was improved without decrease of strength. This should be due to not only crack deflection by dispersed SiC particles with high Young's modulus, but also the phase transformation of t-ZrO2 accelerated by the residual stresses from coefficient of thermal expansion mismatch between 3Y-TZP and SiC.