Interfacial reaction and mechanical properties of diffusion bonded titanium/17-4 PH stainless steel dissimilar joint using a silver interlayer

Abstract

Abstract Diffusion bonding of titanium (Ti) to 17-4 PH high strength stainless steel is challenging owing to the formation of brittle Ti-Fe intermetallic compounds (IMCs) at joint interface. In the current study, it was demonstrated that such detrimental Ti-Fe IMCs can be effectively eradicated by using a silver (Ag) interlayer. The diffusion bonded Ti/Ag/17-4 PH stainless steel is characterized by Ti-Ag solid solution, TiAg, remnant Ag interlayer and Ag-(Fe, Cr, Ni) interdiffusion layer. The interfacial reaction phase TiAg exhibited no detrimental effect on bonding strength. During tensile test, ductile fracture took place in the remaining Ag interlayer of resultant joint. Bonding strength up to ∼420 MPa was obtained over bonding durations in the range of 15 ∼ 25 min. It is thus concluded that using an Ag interlayer is highly appealing in improving bonding strength of diffusion bonded Ti/17-4 PH stainless steel dissimilar joint.