Effect of R-DSFSW on Mechanical and Metallurgical Properties of Commercial Pure Aluminum

Double shoulder Friction stir welding (DSFSW) is a relatively new solid state technique for welding of aluminium alloys. There was wastage of material during welding and material removed region will create notch effect which causes stress concentration. This problem was solved by the introduction of a refilling method and named as refilled double shoulder friction stir welding (R-DSRSW). In this method a 3 mm thick commercial pure aluminium plate was kept at the bottom of joint line. While the tool is traversed through the joint line as in DSFSW at constant feed rate of 25 mm/min, welding takes place without any material loss. The welds were made in butt joint configuration at three different tool rotational speeds namely 900 rpm, 1120 rpm and 1400 rpm. Macrostructure, microstructure and micro hardness studies have been carried out. Finally the results obtained from both DSFSW and R-DSFSW have been compared.