Comparative Study of 5A06 Aluminum Alloy Welded Joints Obtained by Different Laser-Tungsten Inert Gas Hybrid Welding

Two different hybrid processes which contain the laser-tungsten inert gas (TIG) double-side welding (LTDSW) and the laser-TIG single-side welding (LTSSW) were applied on 5A06 aluminium alloy sheets. The three-dimensional (3D) finite element models are developed to investigate the thermally induced stress field during the hybrid welding. Based on the thermal history data obtained from these combined heat source models, the residual stress distribution in weld metal, heat affected zone and base metal characteristics have been calculated and found to be in reasonable agreement with the X-ray diffraction (XRD) experimentally measured values. The results show that the longitudinal residual stress in the LTDSW welded joints is less (10-12 %) than that of the LTSSW welded joints. Meanwhile, from the mechanical and metallurgical point of view, it could be confirmed that it makes a good sense to use LTDSW instead of LTSSW for the 5A06 aluminium alloy welding structure.