In the present work, an attempt has been made to join the aluminium-silicon based metal matrix composite reinforced with TiB2 using friction stir welding technique, which was fabricated using the mixed salt route. A flame hardened bimetallic tool made of tool steel with titanium alloy probe was used to study the effect of varying tool shoulder dimension, welding speed and tool rotational speed on the UTS,% elongation and micro-hardness of the butt welded joints. Further, the welded plates were evaluated for microstructural analysis, which shows a uniform distribution of the fine grains with equiaxed grain structure of reinforcement particles in the stirring zone. The hardness values at the stirring zone were found to be higher than the base metal. The values of UTS ranges from 125 MPa to 141 MPa for all combinations of process parameters and tool types. Fractographs of the welded specimens predict mixed nature of the fracture surfaces.