Study on mechanical properties of laser welding of titanium alloy thin wall T-joint

The laser welding process of TC4 titanium alloy T-shaped joints with 1.5mm vertical rib and 2mm base plate were carried out.The mechanical properties of the joint were tested and the microstructure of the joint was observed.The results show that the tensile strength,yield strength and elongation of the joint with vertical reinforcement are equivalent to the base material.The normal zone after removing the vertical reinforcement has the highest tensile strength and yield strength,while the starting arcing zone has the lowest tensile strength and yield strength.However,the ending arcing zone has the highest elongation and the starting arcing zone has the lowest after removing the vertical reinforcement.The shear performance of the joint improved 3.4%compared to the base material.No fracture occurred in the durable test specimen.The microstructure of the joint weld zone is composed of large columnar crystals,mainly composed of α phase,α'phase and β phase.With the increase of distance from the weld center,the grain size of the joint decreases and the size of α'phase also decreases.