In this study, fabrication of Al-TiC، Al-B 4 C، Al-TiC-B 4 C composites containing different percents of TiC and B 4 C powders by casting techniques was studied. The density of TiC (4.93 g/cm 3 ) is higher than A1 (2.71 g/cm 3 ) and as a result TiC particles deposit in melt. These particles tend to agglomeration, which can be dissolved by intense stirring during the melting process. Furthermore casting techniques suffers from poor wettabilty and distribution of the reinforcement particles in the matrix. The oxide film prevents the Al melt from achieving intimate contact with the ceramics such as TiC and its breakdown at high temperatures is vital to achieve wetting. To overcome these problems, addition of alloying element to melt, injection of reinforcement to melt in the form of (Al -B 4 C p ) cp composite powders and heat treatment of reinforcement particles and using of the Na 3 AlF 6 were investigated. After completion of the injection and distribution TiC p in melt aluminium, melt composites were solidified under a vertical pressure of 100MPa. Before pouring melt composites in die the slag was separated from surface melt. The volume fraction of porosity and its size and distribution in a cast metal matrix composite play an important role in controlling the material's mechanical properties. Porosity cannot be fully avoided during the casting process, but it can decrease with extra processing such as squeeze casting. Microstructural characterization of the samples was investigated by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffractometer (XRD). The results showed that heat treatment of B 4 C powders and using of the flux with TiC powders improve the wettability and distribution of reinforcement particles in the solidified matrix. Heat treatment of ceramic particles decreases absorbed gases from the particle surface and enhances the wetability. Also the flux removes the oxide film from the molten metal surface and facilitates spontaneous incorporation of the particles into the melt. Evaluation of mechanical properties included hardness, tensile properties and wear behavior was performed. The results of mechanical properties showed that the hardness, yield and ultimate tensile strength of composite samples improved in compare with pure Al. Also comparison of composites showed the better mechanical properties for Al-7.5%TiC-7.5%B 4 C hybrid composite. Also the surface of samples revealed low friction coefficients and wear rates for Al-7.5%TiC-7.5%B 4 C hybrid composite, which were significantly lower than those obtained for other samples. The wear mass loss of the pure Al, Al-10TiC, Al-B 4 C, Al-5vol.%TiC-5%B 4 C and Al-7.5vol.%TiC-7.5vol.%B 4 C composites after 1000m sliding distance were 82.5, 36, 21, 25.2, 13.8 mg, respectively. Scanning electron microscopy tests revealed different wear mechanisms on the surface of the warn test specimens. Key Words Casting, Hybrid Composite, Wettability, mechanical properties, Wear
