Effects of temperature on interfacial evolution and mechanical properties of pure titanium and carbon steel sheets bonded via new multi-pass continuous hot-roll diffusion with nickel interlayer

This study performed experiments and thermodynamic calculations to elucidate the effects of diffusion temperature on interfacial evolution and mechanical properties of pure titanium and carbon steel (i.e., steel) sheets bonded via a new type of multi-pass continuous hot-roll diffusion with nickel interlayer. The interfacial evolution results revealed that this new type of multi-pass continuous hot-roll diffusion treatment showed a very good adherence due to its metallurgy bonding, because it made a remarked improvement between compound and intermetallic compound relationship. Secondly, in mechanical properties, results revealed that the highest shear strength (∼470 MPa) was obtained at a processing temperature of 850°C. The highest peel strength (∼21 N/mm) was obtained in the sample processed at 900°C. Bonding temperatures above and below these levels reduced the bond strength respectively due to poor atom diffusion and excessive compound formation, resulting in joint failure at the Ti-Ni interface. Extensive cleavage planes with various alignments were observed on the fracture surfaces in these cases. Overall, a hot-rolling temperature of 850°C was found to provide the optimal tradeoff between interfacial bonding strength and ductility. This work provided an economical and convenient solution for broadening the engineering application of interface between sheets of pure titanium and steel.