The microstructural evaluation and mechanical properties of Al 6061-T6 friction stir welding joint with varied parameters

Friction stir welding is an effective process for joining aluminium alloys and can significantly diminishes grain measure giving superb plastic deformation properties. Therefore, Friction stir welding is utilized in a wide range of welding applications that requires lightweight designs and increased joint reliability. The present experimental work examines the microstructural development and mechanical properties of friction stir welded Al 6061-T6 with varied welding parameters. The joining process was conducted with varied process parameters namely the rotational speed and traverse speed on butt joints with plate thickness of 6mm. The experimental method was based on a full factorial design with varied parameters between 350-1400 rpm and 0.2-4.6 mm/s for rotational speed and traverse speed respectively utilizing three levels for each parameter. The effect of zone formation on tensile strength properties and hardness profile were discussed and concluded. The best mechanical properties are obtained at higher traverse speeds with moderate rotational speed probably owing to the incidence of homogeneous grains and higher heat input. Two parameter variations displayed a combination of good weld class quality and mechanical properties namely rotation speed 950rpm with 4.6 mm/s traverse speed as well as 650 rpm rotation speed with 2.4 mm/s traverse speed.