Interface behavior and mechanical properties of double-sided electron beam welded joint of Ti/Al laminate plates

Ti/Al laminated composite plates have the advantages of high strength and corrosion resistance of titanium alloy, light weight and low price of aluminum alloy, and have a wide range of potential applications in aerospace, automobile manufacturing, underwater equipment and other fields. In order to investigate the connection behavior of Ti/Al laminated composite members, vacuum electron beam welding (EBW) was used to weld Ti/Al laminated composite members, and the microstructure, interface behavior and mechanical properties of the welded joints were studied. The results showed that: Compared with single-side welding, the mechanical properties of welded Ti/Al laminated composite plates can be effectively improved by double-sided Al welding followed by Ti welding. There are no obvious defects at the interface of welded Ti/Al joints, and there are obvious intermetallic compounds (IMCs) layers at the interface of welded Ti/Al joints. The formation sequence of the compounds is TiAl₃, TiAl and TiAl₂. TiAl₂ is the product of a series of reactions in which TiAl is used as an intermediate. Under the condition that the electron beam of Al layer remains unchanged at 43 mA, with the increase of the electron beam of Ti layer, the tensile strength and elongation of the welded joint both increase first and then decrease. The maximum tensile strength and elongation can reach 304.6 MPa and 10.4%, which is 57% of the strength of the base metal. The fracture mechanism of welded joint is mainly brittle fracture at IMCs position.