Study on the Joining of Titanium and Aluminum Dissimilar Alloys by Friction Stir Welding

Titanium alloy TC1 and Aluminum alloy LF6 were butt jointed and lap jointed by friction stir welding (FSW), and the influence of process parameters on formation of weld surface, cross-section morphology and strength were studied. The results show that, Titanium and Aluminum dissimilar alloy is difficult to be butt joined by FSW, and some defects such as cracks and grooves are easy to occur. When the tool rotation rate is 950 r/min and the welding speed is 118 mm/min, the tensile strength of the butt joint is 131MPa which is the highest FSW is suitable for lap joining of TC1 Titanium alloy and LF6 Aluminum alloy dissimilar materials, an excellent surface appearance is easy to obtain, but the shear strength of the lap welding joint is not high. At the welding speed of 60 mm/min and the tool rotation rate of 1500 r/min, the lap joint has the largest shear strength of 48 MPa. At the welding speed of 150 mm/min and the tool rotation rate of 1500 r/min, crack like a groove occurs on the interface and the shear strength is zero.