On the Characteristics of Friction Stir Welding Lap Joint of Magnesium and Aluminum

Lap joints of commercially pure magnesium plates to aluminium plates (Magnesium plate on the top, and Aluminium plate, grade 1100, on the bonom aide) were conducted byfriction stir welding using various traveling and rotation speeds of the tool to investigate the effects of the welding parameters on thejoint characteristics and strength. Defect-free lapjoints were obtained in the welding traveling speed range of 40-80 mmlmin, and rotational speed range of 1200-1600 rpm. The shear tensile strength of Mg/Al joints increased aa a result of decreasing the welding speed from 120 to 40 mmlmin at constant rotation speed of 1600 rpm. Defects such aa surface grooves, excessive flash, tunnels, and voids were observed if the joints prepared out of the mentioned range. The effects of the welding parameters are diacuaaed metallographically baaed on observations with optical and scanning electron microscopes.