✓ The tensile tests show that friction stir processing has increased the tensile and ultimate strength of the composites by an average of 181% compared to the base metal. Applying friction stir processing changes the material's microstructure by refining grain distribution and eliminating the defects and micro-voids. The strength of the composites with additives is affected by the size of the particles, as the micro-alumina sample shows 42 % higher strength than the nano-alumina sample.