In this study, a three-dimensional model involving heat transfer and melt flow is established to study the influence of the focus position and incident beam angle on the molten pool behavior in electron beam welding of aluminum alloy. The effects of gravity, surface tension and recoil pressure are considered during the simulation process. The formation process of a dynamic keyhole is also investigated. Numerical results indicate that a nail-shaped weld seam with the large aspect ratio is easily formed at the defocus of 0 mm and a wedge-shaped weld seam with the small aspect ratio is easier to appear at the defocus of −8 or +8 mm. The keyhole and molten pool are inclined along the incident direction of the electron beam. Besides, a wider and shallower keyhole could be found with an incident angle of 30° or 150°. The processing parameters at the defocus of 0 mm and with beam inclination angle greater than 90° are helpful to improve the weld quantity. Moreover, the corresponding welding experiments are performed to verify the precision of the numerical models applied in this work. The simulated weld results agree well with the experimental data.

在这项研究中，建立了一个包含传热和熔体流动的三维模型，以研究焦点位置和入射束角对铝合金电子束焊接中熔池行为的影响。在模拟过程中会考虑重力，表面张力和反冲压力的影响。还研究了动态锁眼的形成过程。数值结果表明，在散焦为0mm时，容易形成长径比大的钉形焊缝，在散焦为-8或+ 8mm时，长径比小的楔形焊缝更容易出现。 。锁孔和熔池沿电子束的入射方向倾斜。此外，可以发现入射角为30°或150°的较宽和较浅的钥匙孔。散焦为0 mm且光束倾斜角大于90°时的加工参数有助于改善焊接量。此外，进行了相应的焊接实验以验证在这项工作中应用的数值模型的准确性。模拟的焊接结果与实验数据吻合良好。