The microstructure, mechanical properties, fracture behavior and tough
ening mechanisms of the Al2O3-25 vol% ZrO2(2 mol% Y2O3)-25 vol% SiCw (
AZS) ceramic composite were investigated by means of XRD, SEM, TEM, EP
MA techniques and three-point bending and Vicker's hardness tests. It
is shown that the material shows an excellent combination of strength
and toughness. The Al2O3 matrix is simultaneously strengthened and tou
ghened by both ZrO2 particles and SiC whiskers. The flexural strength
and indentation toughness of the AZS at room temperature are 676 MPa a
nd 10.8 MPa m1/2, respectively. The load-displacement curve of three-p
oint bending of the AZS is sawtoothed in shape which is the result of
repeated initiation and stopping of crack propagation by whiskers. Fin
ally, a model of the toughening mechanisms of both ZrO2 particles and
SiCw is discussed.