Interfacial evolution of explosively welded titanium/steel joint under subsequent EBW process

Electron beam welding of titanium alloy to mild steel with a transition joint prepared by explosively welding method was carried out. The interfacial structure of explosive weld and tensile strength of the joint were affected significantly by the distance between electron beam weld and explosive weld. When the electron beam weld was 1.5 mm away from the explosive weld, the explosive interface layer was liquefied during electron beam welding process, which was consisted of Fess, Fe + Fe2Ti eutectic, FeTi + Fe2Ti peritectic and Ti + Fe2Ti eutectic from the Fe side to the Ti side. When this distance increased to more than 3 mm, the thickness of interfacial intermetallic compounds in explosive weld decreased sharply from 40 μm to lower than 3 μm. The interface layer kept in solid state and diffusion of Ti and Fe atoms occurred across the interface. When the electron beam weld was located 6 mm away from the explosive weld, the maximum tensile strength of 418 MPa was obtained. In this case, the residual stress across the explosive interface induced by electron beam welding reached to the lowest value in this experiment.