MECHANICAL-PROPERTIES OF SINTER-FORGED AL2O3-ZRO2 CERAMICS

Two kinds of composites, Al2O3-25 wt% ZrO2(2 mol% Y2O3) (Y-ZTA), AL(2) O(3)-25 wt% ZrO2(8 mol% CeO2) (Ce-ZTA) were produced by the sinter-for ging process. The effect of presintering temperature on the mechanical properties of the composites was examined. The sinter-forging process increased the room-temperature bending strength in comparison with pr essureless sintering, owing to the smaller grain size in sinter-forged bodies than in pressureless sintered ones. It was found necessary to keep the presintering temperature considerably lower than sinter-forgi ng temperature in order to improve the room-temperature strength. The strength of sinter-forged Ce-ZTA was higher than that of sinter-forged V-ZTA. The residual surface compressive stress induced by the phase t ransition during grinding in Ce-ZTA was found to be effective to furth er improve the strength and fracture toughness.