To improve strength and creep resistance of MoSi2, WSi2 and TiSi2 reinforcing phases are added to produce silicide composites. Their effect depends on size and shape. Common composites of these silicides are based on addition of SiC, Si3N4 and other silicides such as TaSi2. An effective silicide added as a strengthener to MoSi2 is Mo5Si3. The low fracture toughness below the ductile to brittle transition temperature in WSi2 is expected to be improved by SiC additions. The improvement in the fracture toughness in WSi2 and TiSi2 is a result of crack deflection and crack bridging.