MECHANICAL PROPERTIES AND RELIABILITY OF Y-TZP/ PLATELET-ALUMINA COMPOSITES BY TEMPLATED GRAIN GROWTH

Alumina platelets and powders coated with 3 wt% CaO-SiO₂ glass and yttria-stabilized zirconia (3Y-TZP) powders were used as starting materials. The compacts were prepared in atmospheric pressure at various temperatures by templated grain growth. The mechanical properties of the composites were investigated. The results show that the composites sintered at proper temperature have high strength (800~900 MPa) and toughness (11.8~15.2MPa·m^1/2). The microstructure of the composites was observed using SEM. The possible mechanism could be attributed to the enhancement of phase transformation from tetragonal to monoclinic during fracture and crack-deflection and bridging produced by the platelike Al₂O₃ grains. The variability in strength was quantified using conventional two-parameter Weibull statistics. The results show that the composite containing higher platelet-alumina has a high Weibull modulus.