FABRICATION AND MECHANICAL-PROPERTIES OF CONTINUOUSLY GRADED WSI2-ZRO2(2Y) MATERIALS USING WET-MOLDING

Continuously graded WSi2-ZrO2(2Y) materials with high density (99.2% o f theoretical) have been fabricated by uniaxial wet-molding, followed by hot pressing (1000 degrees C/1h/30MPa) and hot isostatic pressing ( 1500 degrees C/2h/196MPa). A mixed solution of glycerin and ethanol wi th the viscosity of approximate to 6 mPa.s has been used as a dispersi on medium in the molding process. The sintered materials show a linear composition profile with a transition from WSi2/ZrO2(2Y) approximate to 75/25 to approximate to 5/95 mol%. Vickers hardness, Hv, for which the value is approximate to 11.2 GPa, is almost independent of the com positional change. Fracture toughness, K-C, increases from 5.6 to 10.3 MPa.m(1/2) with increasing ZrO2(2Y)composition. (C) 1998 Elsevier Sci ence Ltd.