Influence of rotation speed on mechanical properties and corrosion sensitivity of friction stir welded AA2024-T3 joints

A study of aluminum alloy 2024-T3 friction stir welded (FSWed) joints under different rotation speeds at fixed travel speed of 200 mm/min is summarized. The effect of rotation speed on the hardness, tensile mechanical properties as well as corrosion sensitivity of the welded joints was explicitly investigated. The results show that the rotation speed has a remarkable influence on the shape and geometry of the stirred zone. Microstructure of the joint varied, while it was shown that microhardness was increased as the rotation speed of the process increased. This was attributed to the formation of high volume fraction of GPB zones under high rotation speed. An optimal in the strength to ductility compromise was obtained for the 600 rpm rotation speed. This was supported by the appropriate grain size and precipitates density and size, resulting in ultimate tensile strength of approximate 420 MPa and elongation at fracture of approximate 8.7%. This welded joint also exhibited the lowest corrosion susceptibility, while the heat-affected zone proved to be more corrosion resistant than the respective friction stir zone.