Experimental Investigation of Material Flow and Welding Defects in Friction Stir Welding of Aluminum to Brass

In this research, the formation of a nugget zone in dissimilar friction stir welding (FSW) of brass to aluminum has been investigated. Also, the main parts of a stir zone (SZ) besides their dependency to the welding parameters are probed. The base materials play the role of marker to reveal the material flow pattern. Investigations carried out by optical microscopy and scanning electron microscopy verifies the formation of three different areas including pin affected zone, shoulder affected zone, and swirling zone within the SZ. Moreover, the various types of defects such as tunneling defect, coarse fragment defect created during dissimilar FSW are analyzed. Also, an attempt has been made to remove the defects by adjusting the welding parameters especially the offset value which features in defects formation.