Analysis of some mechanical properties of friction stir welded joints of AA6101 and AA6351 aluminum alloys under T6 condition

Abstract

Abstract Friction In the present work, friction stir welding has been carried out with AA 6101-T6 and AA 6351-T6 dissimilar aluminium alloys (plate thickness being 6 mm). The different the process parameters are tool rotational speed, weld speed and axial force and a cylindrical threaded profile tool pin have been used. For the fabrication of the joints the experiments have been carried out with a tool shoulder diameter 18 mm and different tool rotational speeds (900, 1100, 1300 and1500 rpm) with constant welding speed 60 mm/min. Visual inspections confirm the absence of external macro defects. The microstructure studies of weld zone reveal mechanically mixing pattern of both the aluminum alloys around the tool pin. X-ray diffraction (XRD) analysis confirms the presence of intermetallic compound Mg2Si in base metals and FSW joints too. Tensile, hardness, bending tests have been conducted. It is found that the rotational speed of 1300 rpm produces better mechanical and metallurgical properties joints compared to joints fabricated by other rotational speeds. Thus mechanical properties of weld joints depends on combined effect of both microstructure of alloys and processing welding parameters. The fracture surface of tensile test samples presents ductile and dimple fibrous fracture.