Pre-forming evaluation of dissimilar aluminium alloys blank fabricated using friction stir welding technique.

Friction stir welding (FSW) is a solid-state welding that is using to weld the relatively difficult to weld materials such as aluminium alloy. FSW also can weld different material type and thickness to produce tailor welded blanks (TWBs). Although FSW capable to join dissimilar material or similar material hence from different grades, the properties of welded blanks may affect as compared to base material. In this study, performance of three aluminium alloy grades i.e. AA6061, AA5052, and AA1100 blanks that were combined among them and evaluated. Furthermore, the effect rolling direction was also considered. The welding was performed at constant speed, welding speed and tool angle using flat pin tool on a conventional milling machine. The performance is based on few mechanical properties such as hardness and tensile strength. In addition, crack pattern on the welded blank was also observed using three-point bending test. Based on the result, the hardness reduced at the stir zone (SZ) as compared to the base material, even though from different rolling direction. As expected, for tensile behaviour, the maximum load can be found on combination of similar material i.e. AA6061-T6 compared than other combinations. While based on the crack pattern, there are unsuitable combinations because of inappropriate welding parameters, and it is complying with the previous observation on tensile properties.