2195铝锂合金和TC4钛合金异种金属电子束焊接行为研究

Electron Beam Welding/Brazing of Al-Li Alloy 2195 and Ti-Alloy TC4 in Vacuum

研究采用真空电子束实现对2195铝锂合金和TC4钛合金的有效连接。通过金相显微镜、扫描电镜、能量色散谱、X射线衍射等技术,分析了焊接接头的微观组织及成分特征,并通过拉伸试验对接头进行了力学性能表征。实验结果表明:铝锂合金2195和钛合金TC4能较好地实现连接,接头未发现明显的气孔和裂纹。在连接界面处,金属间化合物以棒状、锯齿状、和胞状等形态生长,其主要成分为Ti Al3。接头在连接较弱的焊缝中心起裂,平均抗拉强度260 MPa。

Here,we experimentally addressed the welding/brazing of Al-Li alloy 2195 and Ti-alloy TC4 with an electron beam in vacuum. The impact of the welding/brazing conditions on the microstructures,phase-structures and mechanical properties of the joint was investigated with scanning electron microscopy,energy dispersive spectroscopy,X-ray diffraction and mechanical probes. The preliminary results show that an electron beam is capable of welding/brazing Al-Li alloy 2195 and Ti-alloy TC4 without oxidation under the optimized conditions. For example,no obvious pores and cracks were observed in the compact joint,comprising a 5 μm thick transition layer,close to Ti-alloy,and TiAl_3 dominated intermetallic compounds in the form of columnar,cellular and pyramid grains grown in transversal orientation to Al-Li alloy side. An average tensile strength of the joint was measured to be 260 MPa; and cleavage fracture might possibly occur in the fairly weak mid-join.