Abstract: A ZTA-SiC_W ceramic composite of room temperature strength 935—1110 MPa and frac- ture toughness 9.7MPa·m~(1/2) was prepared using the sol-gel proeess.Its microstructure and fracture feature have been examined by means of X-ray diffraction analysis and electron mi- croscope observations.The results show that the whiskers are well dispersed and the matrix has an obvious texture character.Between the whisker and matrix,there is a great number of transcrystalline and transcrystalline connective relation other than part of conventional polycrystalline connective ones.Certain secondary cracks closely related with local whisker group are found on the fracture surface.It may be a new reinforcing and toughening mecha- nism by whisker group,of which the whiskers in the local whisker group arrest synergetically the crack propagation accompaning with the formation of secondary cracks.

Key words: ceramic composite, microstructure, fracture