The spray-formed 7055 aluminum alloy is welded by electron beam welding. Combined with the numerical simulation of a welding temperature field, the effect of different welding procedures on the microstructure and mechanical properties of welded joints is investigated in this study. Results show that the joints with good properties can be obtained under proper welding procedures. The microstructure analysis demonstrates that the fusion zone mainly consists of equiaxed grains, while a fine equiaxed grain zone is formed near the fusion line. There are mainly α(Al), MgZn₂, Al₂CuMg, and Mg₃₂(Al,Zn)₄₉ phases in the weld metal. The morphology of the weld can be improved by modification welding after the first bead welding, which is also advantageous to the mechanical properties of a welded joint. In the as-welded condition, compared with that of the base metal, the hardness of the weld zone decreased to a certain extent. The maximum tensile strength of a welded joint reaches 371.7 MPa. There are many dimples on the tensile fracture surface of a welded joint, and it dominantly presents the characteristic of ductile fracture. The simulated molten pool is consistent with the experimental weld morphology, and the reliability and accuracy of the simulation analysis are verified.

中文翻译：

---

喷射成形7055铝合金电子束焊接的数值模拟和实验研究

喷射成形的7055铝合金通过电子束焊接进行焊接。结合焊接温度场的数值模拟，研究了不同焊接工艺对焊接接头组织和力学性能的影响。结果表明，在适当的焊接程序下可以得到具有良好性能的接头。显微组织分析表明，熔合区主要由等轴晶组成，而在熔合线附近形成了细等轴晶区。主要有α（Al），MgZn ₂，Al ₂ CuMg和Mg ₃₂（Al，Zn）₄₉焊缝金属相。可以在第一道焊道焊接之后通过变质焊接来改善焊接的形态，这也有利于焊接接头的机械性能。在焊接状态下，与母材相比，焊接区的硬度有所降低。焊接接头的最大抗拉强度达到371.7 MPa。焊接接头的拉伸断裂面上有许多凹坑，并且主要表现出韧性断裂的特征。模拟的熔池与实验焊缝形态相吻合，验证了模拟分析的可靠性和准确性。