Effect of Heat Input on Tensile Properties of Friction Stir Welded AA6061-T6 and AA7075-T6 Dissimilar Aluminum Alloy Joints

Friction Stir Welding (FSW) is a solid state process widely used to join dissimilar aluminium alloys. High quality and strength joints can be fabricated using this technique when compared to other conventional methods. The welding parameters play major role in determining the quality of the weld. This paper aims in presenting the effect of heat input on tensile properties of the joints between AA6061-T6 and AA7075-T6 aluminium alloys. A total of 15 experiments were conducted by varying the tool rotational speed from 600 RPM to 1400 RPM in a step of 200 RPM, welding speed of 32 mm/min, 45 mm/min and 53 mm/min, axial load form 3 kN to 5 kN in an increment of 1and shoulder diameter from 12 mm to 18mm. Microstructural characterization and the tensile strength were measured for the various heat inputs and analysed. The joint fabricated with the intermediate heat conditions yielded the maximum tensile strength. The formation of finer grains and proper material mixing in the stir zone are the main reasons for the superior tensile strength.