The energy synergistic mechanism of coaxial heterogeneous-wavelength hybrid laser beam and its effect on welding molten pool dynamics for aluminum alloy

被引:4
作者
Zhao, Yanqiu [1 ]
Zhan, Xiaohong [1 ]
Ma, Longfei [1 ]
Bu, Hengchang [1 ]
Li, Yue [1 ]
Ma, Chao [1 ]
机构
[1] College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing
关键词
Heterogeneous-wavelength hybrid laser beam welding; Keyhole; Molten pool; Thermal-flow behavior;
D O I
10.1016/j.jmatprotec.2024.118605
中图分类号
学科分类号
摘要
The coaxial heterogeneous-wavelength hybrid laser beam (HW-HLB) heat source featuring a “Gauss + Flat top” energy distribution, which integrates the 1080 nm and 915 nm laser beam, was employed in this paper to achieve excellent stability in the welding of aluminum alloy. The interaction mechanism between aluminum alloy and laser beams with different wavelengths was taken as a point cut to explore the synergistic enhancement mechanism of coaxial HW-HLB. A thermal-fluid coupling model for HW-HLB welding, considering the synergistic effect of dual lasers, was established according to the welding experiment results. The influence of fiber laser power (PF) and diode laser power (PD) on the molten pool flow behavior during welding process was investigated. The dynamic of the molten pool and the maintenance mechanism of the keyhole were elucidated through in-situ monitoring experiments and thermal-flow simulations. The results indicated that, in contrast to the single fiber laser beam (FLB), the power density of HW-HLB presents a significant increase, which results in the “avalanche-like” augmentation of the plasma plume, as well as deeper depth of the keyhole. The energy synergistic enhancement effect of coaxial HW-HLB with PF=2800 W and PD=2500 W performs stronger and thorough changes in the morphology and flow behavior of the molten pool. The introduction of 915 nm laser beam improves the multi-reflection behavior in the inner keyhole. The findings of our research provide a theoretical framework for improving the stability of the laser weld molten pool and the quality of welds in aluminum alloys through the implementation of HW-HLB. © 2024 Elsevier B.V.
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