Abstract: The microstructure and mechanical properties of Al2O3 -25 vol % ZrO2 (2mol% Y2O3)-25 vol% SiCw(AZS) ceramic composite are investigated by means of XRD, SEM,TEM and EPMA in the paper. The experimental results show that the material possesses a good combination of strength and toughness. This is considered as a result of combining contribution of the transformation and microcrack toughening of ZrO2 particles with the bridging and pull-out effect of SiC whiskers and bending and deflection of whiskers on cracks. The decrease of Young's modulus associated with ZrO2 additives is inhibited effectively by adding SiC whiskers, and the flexural strength and Vicker's hardness of AZS are also increased by SiC whiskers and ZrO2 particles dispersed in Al2O3 matrix. Moreover, the indentation toughness of hot-pressed AZS shows a clear orientation. The fracture toughness and flexural strength of AZS measured at the room temperature are 10.8MPam1/2 and 676 MPa respectively.

Key words: ZrO, SiC whisker, ceramic matrix composite, toughening, strengthening