Contact Reactive Joining of TA15 and 304 Stainless Steel Via a Copper Interlayer Heated by Electron Beam with a Beam Deflection

TA15 titanium alloy and 304 stainless steel were joined via a copper interlayer heated by electron beam with a beam deflection towards the stainless steel. Microstructures of the joints were analyzed by optical microscopy, scanning electron microscopy, and X-ray diffraction. The tensile strengths of the joints and the ultramicrohardness of the intermetallic compounds were also measured. The results showed that the joint was formed by three kinds of metallurgical processes. Copper interlayer and TA15 were joined by contact reaction with the reaction products of CuTi, Cu₄Ti₃, and Cu₂Ti. While copper interlayer and 304 stainless steel were joined by fusion and solid state diffusion process. Tensile strength of the joint can reach to 300 MPa, equivalent to 55% of that of 304 stainless steel. Furthermore, the tensile strength was mostly dependent on the volume of the unmelted copper sheet, although the intermetallics layer was the weakest location in the joint.