The influence of keyhole dynamic behaviors on the asymmetry characteristics of weld during dissimilar materials laser keyhole welding by experimental and numerical simulation methods

The joining of dissimilar materials has been attracted more and more attention and widely used in the manufacturing of complex structural components. Due to the difference of thermophysical parameters of ma-terials, the formed weld tends to show the asymmetry characteristics including geometric morphology and alloy compositions during the process of dissimilar materials laser welding. Therefore, a 3D multiphase flow model is proposed in this paper to investigate the asymmetry characteristics of weld formed in the dissimilar materials laser keyhole welding. The results obtained from the molten pool behaviors calculation under different welding conditions are compared and the effects of welding conditions on the molten pool behaviors induced by keyhole generation are discussed in detail. The weld geometries and alloy compositions distribution under different welding process conditions are obtained. Simultaneously, the effects of keyhole dynamic behaviors on the geometrical morphology of weld and asymmetry distribution of alloy compositions are analyzed. The good agreement between the calculated and experimental results is found, which approves that the developed model can be used to improve the weld geometric morphology and alloy compositions. Hence, the proposed method is efficient for welding process improvement to obtain the desired welded joints in practical dissimilar materials laser keyhole welding.