ABSTRACT The purpose of this study is to determine the influence of scarf joint configuration on friction stir welding (FSW) of as-cast AA7075/TiB2 aluminium matrix composites (AMCs), as well as the effect on mechanical and microstructure aspects. The experiment was conducted by varying the reinforcement weight percent (wt %) in the parent material (6%, 9%, and 12%) and the welding was carried out on the casting plate at constant tool traverse speed (TTS) of 1.5 mm/s, tool rotating speed (TRS) of 1200 rpm, and tool tilt angle (TTA) of 1.5°, respectively. The composites were made by mixing K2TiF6 and KBF4 inorganic salts with molten aluminium and joining them with an FSW machine. Macrostructural examination demonstrates that all the FSW specimen are structurally defect-free. The microstructural examination revealed that the nugget zone (NZ) comprised fine equiaxed grains while the thermo-mechanically affected zone (TMAZ) had elongated grains. The maximum and minimum ultimate tensile strengths (UTS) were obtained using 12 wt.% and 6 wt.% reinforcement, respectively. The welded joint’s hardness increases as the reinforcing content of the parent material increases. Fractography analysis revealed that the welded joints fractured in ductile and mixed modes.