Electron beam welding was carried out between aluminum alloy and steel with Ag interlayer.Seam morphology,structure and mechanical properties of the joints were investigated with different action positions of the electron beam spot.The results show that with the increment of the beam offset to the silver side from the interface between silver and steel,the seam morphology was improved,and the porosity in the Ag interlayer vanished.A transition layer mainly composed of Ag2Al and A1 eutectic was formed at the interface between silver and aluminum,and became thin and spiccato as the beam offset increased.When the beam offset was too large,two IMC layers composed of FeAl and FeAl3 respectively were formed at the interface between steel and Ag interlayer.The optimal beam offset was 0.2 mm,and the maximum tensile strength of the joint was 193 MPa,88.9％ that of the aluminum alloy,and the fracture occurred at the interface between steel and Ag interlayer.%在铝合金与钢之间添加Ag中间层后进行电子束焊接实验.其他参数固定的情况下,对电子束作用位置不同时的焊缝成形、接头组织和力学性能进行分析.结果表明:随着电子束斑点从银-钢对接面向银侧偏移距离的增大,焊缝成形明显得到改善,接头中的气孔缺陷消失.在银-铝对接面形成由Ag2Al和Al共晶组成的过渡层,过渡层随着偏束距离的增大而变窄且不连续.当偏束距离过大时,在银-钢界面上形成FeAl和FeAl3两种化合物层.当电子束最佳偏束距离为0.2 mm时,接头强度最高达193 MPa,为铝母材的88.9％,此时断裂发生在银-钢界面上.
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