The feasibility study on AA7075 T-joint via friction stir welding process

Development of research on aluminum light joints is one of the most effective ways to reduce fuel consumption¡ increase strength and development of aerial structures. In this study¡ the feasibility of Tjoint AA7075 aluminum alloy with using friction stir welding process was studied. For this purpose the AA7075 aluminum joint with different tool offset¡ plunge depth¡ linear and rotational speeds were studied. In order to better understanding the production and distribution of heat¡ welding process was simulated using commercial fluent package software. Depending on the selected parameters in the process¡ the strongest connection was produced in the 1.5mm tool offset on advancing side¡ the 0.4 mm plunge depth¡ 2o tool tilt angle¡ and 1325 rpm rotational speed and 69 mm/min linear velocity¡ respectively. The failure position of all tensile samples was located on the T appendage. Tunnel void was the major defect in the joints which disappeared with increased heat input and cooling rate. The strongest connection which produced in these experiments had 181 MPa strength that nearly 80% of the aluminum base metal. The connection elongation after the tensile test was close to 11 mm.