Influence of Welding Parameters on Weld Formation and Microstructure of Fiber Laser Beams Welded T-Joint of Aluminium Lithium Alloy

Abstract

This paper focused on the welding 1.2 mm thick 2A97 aluminium lithium (Al-Li) alloy plates in T-joint form using fiber laser with ER2319 aluminium filler wire. The effects of welding parameters on the T-joint weld appearance, microstructure and the joint mechanical properties were studied systematically, and the influence of welding parameters including the incident beam position and the incident beam angle. The weld shape, microstructure, hardness of the joint were evaluated by optical microscope and micro-hardness test. A uniaxial tensile test was conducted to obtain the tensile property of welded joints. At the optimized parameters, the welded T-joints showed good weld shape without macro defect. The significant softening occurred at the weld zone of the T-joints, and the micro-hardness of the weld ranged from70 to 85 HV0.2. The tensile strength was about 432 MPa, and the fracture mode of tensile specimens of T-joints was mixed.