Effect of Skewness during Friction Stir Welding of Dissimilar Aluminium Alloys EN AA 5083-H116 and EN AA 6082-T6 Including Fracture Observations

The corrosive resistant aluminium-magnesium alloy AA 5083-H116 and aluminium-silicon alloy AA 6082-T6 is widely used in ship building, marine and various structural applications. FSW is an emerging solid state joining process suitable for joining the aluminium alloys with minimized formation of weld defects like cracks, porosity etc. compared to other fusion welding processes. This research work presents FSW of EN AA 5083-H116 and EN AA 6082-T6 using skew tool pin profile with the consideration of influential process parameters like tool rotational speed of 710 and 900 rpm at constant traverse speed of 16 mm/min. Radiographic inspection has been performed for evaluating the weldments soundness. From the radiographic results it has been found that at higher rpm i.e at 900 rpm the occurrence of lack of fusion is more compared to the weldment fabricated at 710 rpm. Tensile properties and fractural observations were carried out on the weldments. It has been noted that good mechanical properties were observed with the weldment fabricated at 710 rpm with high tensile strength of 160 MPa. From the fractural observations it has been observed that all the specimens are prone to ductile fracture, besides shear lips were observed at specimens fabricated at 900 rpm.