Optimization of Maximum Tool Travel Speed for Friction Stir Welded AA-2014-T6 without Compromising the Mechanical Properties

Abstract

In this study optimization of maximum travel speed that can be achieved for Friction Stir Welding of Aluminum Alloy 2014-T6 without compromising the mechanical properties was carried out. Joints were made at different travel speeds of 200, 300, 400, 500 and 600 mm/min with constant tool rotational speed of 800 rpm and tool tilt angle of 2.The samples were characterized by stereo microscopy, optical microscopy, scanning electron microscopy, Vickers microhardness testing and tensile testing. Microstructural features of as-welded samples revealed refined equiaxed grains in nugget zone and grain growth in the heat effected zone. Tensile test results showed that the tensile strength was maximum at travel speed of 500 mm/min but then decreased after further increasing the travel speed. Hardness in the nugget zones of all welds was lower than that of base material. Fractographic analysis exhibited significant variations in fracture surfaces of tensile samples. A relationship between the welding parameters and resultant heat inputs was also discussed.