Microstructural and mechanical properties of dissimilar aluminum alloys/Al2O3 nanocomposite joint via friction stir welding

In this study, AA5083-H116 and AA7075-T6 aluminum alloys are joined by friction stir welding (FSW) and incorporating alumina nanoparticles into the joint to produce an aluminum alloys/Al2O3 nanocomposite. The joining process is carried out-by using a square pin profile tool at rotational and traverse speeds of 800 rpm and 50 mm/min, respectively. Microstructural investigation by scanning electron microscopy (SEM) and optical microscopy (OM) are revealed a clustered structure that consists of Al2O3-rich and Al2O3-free areas in the stir zone (SZ). Besides, it is observed that the grain size of the joint is reduced after addition of nanoparticles. Moreover, owing to the presence of Al2O3 nanoparticles, the resultant hardness profile shows the superior hardness of the reinforcement-included specimen, while the ultimate tensile strength and percentage of elongation are reduced.