MECHANICAL-PROPERTIES OF AL2O3 PARTICLE-Y-TZP MATRIX COMPOSITE AND ITS TOUGHENING MECHANISM

Dense Al2O3 particle Y-TZP matrix (Al2O3 < 40 vol %) composite was prepared by pressureless sintering at 1550-degrees-C. Composites with 10-30 vol % Al2O3 particles showed enhanced fracture toughness, bending strength and Vicker's hardness as compared to single-phase Y-TZP. The highest strength (1150 MPa) and highest toughness (12.4 MPa m1/2) were obtained for the composite containing 10 vol % Al2O3. It was found that, in addition to the contribution by the crack-deflection effect, the enhanced phase transformation from tetragonal to monoclinic during fracture was the main toughening mechanism in operation in the composites.