Surface layer in many engineering applications is strengthened by ceramic grains where the main parts have higher structure toughness than the original material. This paper presents the effect of four process parameters that have been taken into consideration using Taguchi technique based on L9 orthogonal array. These parameters are;1) transverse speed, 2) type of nano- powders, 3) rotational speed, and 4) groove’s depth friction stir welding T-joints aluminum alloy 6061-T6. This work combines welding T-joint sections and creating MMNCs in welding region simultaneously. The predicted optimum parameters and their percentage of contribution are estimated, utilizing the analysis of variance and signal to noise ratio techniques, depending on tensile test in skin and stringers direction, and hardness test of the joint. Optical microscope and scanning electron microscope (SEM) analysis are used to verify the microstructure and dispersion of nano-powders in welding joint. The best ultimate tensile stress (UTSskin) equal to (177MPa) for the skin welded part was obtained at the optimal conditions of 1550rpm rotational speed, 15mm/min transverse speed, Al2O3 type of powder and 1mm groove’s depth. SEM micrographic for metal matrix nanocomposite of all nine experiments revealed that the nano-particles are irregularly dispersed in nugget zone due to one pass. The rotational speeds of 960rpm, the transverse speed of 15mm/min, type of powder TiO2, and groove’s depth of 1.5mm, give the greatest hardness value of 80HV in nugget zone. The analysis of variance shows that the groove’s depth is the most significant parameter in this investigation.