Dissimilar friction stir welding between magnesium and aluminum alloys

Abstract Dissimilar friction stir welding between magnesium and aluminum alloy plates with thicknesses of 2 mm was performed. The tool for welding was rotated at speeds ranging from 800 to 1600 rpm under a constant traverse speed of 300 mm/min. For tool rotation speeds of 1000, 1200, and 1400 rpm, defect-free welds were successfully obtained and the surface morphology of the welds became smoother as the tool rotation speed was increased. The relatively simple bonded interface was clearly evident and had a zigzag pattern. A mixed microstructure of magnesium and aluminum alloys was formed near the bonded interface. The maximum tensile strength of about 132 MPa was obtained at the tool rotation speed of 1000 rpm. However, there were not noteworthy changes in the tensile strength as a function of the tool rotation speed. The elongation was 2% or less, regardless of the tool rotation speed.