Laser-Tungsten Inert Gas (TIG) Hybrid Welding of a 5052 Aluminum Alloy, Part A: Weld Bead and Microstructural Analysis
X-H. Xu, X-F. LI, Z-J. Kang, W-G. Zhai, P. Hua and W. Zhou
Based on 5052 aluminium alloy, the influence of two hybrid modes (laser-leading and arc-leading) of laser-tungsten inert gas (TIG) hybrid welding with a Nd:YAG laser on weld bead appearance and microstructure was studied. The results show that the forming quality of weld surface in laser-leading mode is better than that of arc-leading mode, and the weld penetration is obviously deeper than that of arc-leading mode. The weld penetration formation mechanism in two hybrid modes is associated with the hybrid state between the laser plasma and the arc plasma. In laser-leading mode, the root of the arc plasma acts on the laser keyhole and connects with the keyhole plasma, and a hybrid discharge happens. The keyhole part of the hybrid plasma possesses extreme electric conductivity, the arc is strengthened by the laser plasma and the current density and the energy utilization are enhanced as well, so the weld penetration in laser-leading mode hybrid welding is deeper than that of arc-leading mode.
Keywords: Nd:YAG laser, aluminium alloy, tungsten inert gas, welding, laser-TIG hybrid welding, penetration depth, bead, microstructure, hybrid mode, hybrid mechanism