Numerical analysis on temperature characteristics and melt flow dynamic behaviors in electron beam welding of dissimilar aluminum alloy lock-butt joint

In this research, the temperature field characteristics and melt flow behaviors of 5A06/6061 aluminum alloy lock-butt joint during the electron beam welding (EBW) process are investigated by numerical simulation involving heat transfer and flow of fluid. The calculated mesh model of the lock-butt joint is established with the computational domain divided into three phases. The rotating Gauss heat source is applied to simulate the electron beam energy loaded on the base metal during the welding process. Immediately, not only the temperature filed distributions on the surface and different sections of the molten pool are analyzed carefully, but the flow behaviors of the liquid metal in the molten pool are studied in detail. The results demonstrate that the asymmetric distribution of the temperature field, keyhole, and molten pool morphology exist constantly during the welding process. Besides, there are asymmetric metal flows on both sides of the molten pool and obvious vortex metal flows near the rear and the surface of the molten pool. The melt flow on the keyhole wall represents diversity including the surrounding, downstream, and upstream flow. Moreover, the corresponding experiment is conducted to verify the accuracy of the established model and the simulation results are in good agreement with the experimental results in this work.