Enhancing the tensile performance of Al/Mg alloy dissimilar friction stir welded joints by reducing brittle intermetallic compounds

In this current research work, magnesium AZ61 (Advancing Side) and aluminum 6061-T6 (Retreating Side) alloys were joined using the zinc interlayer friction stir welding technique at the optimum process parameters. The aim of this work is to propose an effective alternative to overcome issues related to aluminum/magnesium joints. This article investigates the effects of zinc foil (0.2 mm) on the weld surface (3 mm aluminum/magnesium plates), intermetallic compound characteristics, microstructure, fracture surface and strength of joint. The emergence and nature of intermetallic compounds during aluminum/magnesium and aluminum/zinc/magnesium friction stir welded joints were studied in detail. As can be seen from the findings, using zinc in aluminum/magnesium friction stir welded joints inhibits the emergence of brittle aluminum-magnesium intermetallic compounds and promotes the formation of magnesium-zinc intermetallic compounds in the stir zone by introducing the zinc interlayer, confirmed through X-ray diffraction analysis. Furthermore, the average tensile performance (181.33 MPa) of friction stir welded aluminum/zinc/magnesium joints was enhanced up to 18.26 % compared to aluminum/magnesium friction stir welded joints (153.33 MPa). The promising results of this research establish an alternative route with a cost-effective technique to enhance the aluminum/magnesium dissimilar joint strength.