Abstract: The in situ synthesized MoSi2-SiC composite is proved to be of higher fracture tough-ness than the monolithic MoSi2. The TEM and HREM study reveals that the interfacebetween MoSi2/SiC is of direct atomic bonding without any amorphous glassy phase,such the SiO2 structure. Based on the fractography and the observation of crack prop-agation path from indentation, it is concluded that the toughening of such compositeat room temperature can be attributed to the high interfacial binding energy, the re-finement of the MoSi2 matrix and the defection and bridging behavior in the crackpropagation.

Key words: MoSi2-SiC composite, synthesized in situ, fracture, toughening at room temperature