Fracture strength and fracture toughness of zirconium titanate–zirconia bulk composite materials

Zirconium titanate–zirconia based materials could be suggested for applications involving temperature variations. The determination of mechanical properties such as fracture strength and fracture toughness is necessary to evaluate the response of materials during their use in these kinds of applications. In this work, fracture strength (σf) and fracture toughness (KIC) of two zirconium titanate–zirconia bulk composites (Z(Y)T70 and Z(Y)T50) have been determined at room temperature by 4 point bending tests and by stable fracture tests using a crack mouth opening displacement (CMOD) as control variable. Furthermore, fracture strength has been determined at high temperature for both composites. Critical defects are responsible for fracture initiation at room and high temperature of Z(Y)T70. Coalescence of microcracks is responsible for fracture initiation at room and high temperature of Z(Y)T50. KIC values for Z(Y)T70 and Z(Y)T50 are 2.1 ± 0.3 and 0.6 ± 0.1 MPa·m1/2, respectively.