Analysis of tensile properties, fracture characteristics, and microstructural features in friction stir welding of dissimilar aluminium alloys reinforced with Al 2 O 3

In the present investigation, dissimilar aluminium alloys AA2014-T6 and AA5083-H111 were joined using friction stir welding combined with in-situ reinforcement of aluminium oxide (Al2O3) particles. A single V-groove with an included angle of 45° was machined along the welded joint line, into which Al2O3 particles were introduced prior to subsequent friction stir processing. The welded joints were subjected to three friction stir processing passes to promote effective material flow and particle dispersion. Microhardness measurements revealed values of up to 105 VHN in the stir zone, while tensile testing showed an improvement of up to 18% compared to the unreinforced joint. Scanning electron microscopy (SEM) observations indicated the distribution of Al2O3 particles and effective mixing within the stir zone, and elemental mapping verified the presence of reinforcement across the processed region. Fractographic analysis indicated predominantly ductile fracture characterized by equiaxed dimples. Wear testing showed that the 9 wt.% Al2O3 condition exhibited the lowest wear rate among the investigated reinforcement levels.