Microstructure characteristics and mechanical properties of laser - TIG hybrid welding joint of TA15 titanium alloy

The laser-tungsten inert gas (TIG) hybrid welding technique is used to weld TA15 titanium alloys. The microstructure and mechanical properties of the welded joint are then analysed systematically. The results indicate that the laser beam can centralise the energy of TIG arc and increase the penetration of weld seam. There are columnar crystals on the top of the weld seam and equiaxed crystals at the bottom. By the way of element analysis, it is found that the major elements, such as Ti, Al, Mo and V, distribute uniformly in the weld seam. Besides, the tensile strength of hybrid welding joint achieves 98% of that of base metal and the fracture of samples proves to be a gliding fracture. The TA15 titanium alloy is joined successfully by laser-TIG hybrid welding in this experiment.