1990 Volume 30 Issue 11 Pages 978-984
A commercially pure titanium has been diffusion-bonded to iron and steels of various carbon contents: low carbon steel with 0.01% C (ULC), mild steel with 0.19% C (S20C) and spheroidal graphite cast iron with 3.75% C (FCD). The tensile strength of joints bonded below 900°C was hardly influenced by the carbon content, and increased with the rise in bonding temperature. Above 900°C however, the strength of the ULC/Ti joint was almost independent of the bonding temperature, that of the S20C/Ti joint decreased with the rise in bonding temperature, and that of the FCD/Ti increased. The interlayer forming along the bond interface consisted only of TiC in the FCD/Ti joint and of TiFe and TiFe2 in the ULC/Ti. Since Ti and Fe diffused over much longer distances in the ULC/Ti than in the FCD/Ti, the TiC layer may be considered to interfere with the interdiffusion of Ti and Fe, and consequently to suppress the formation of TiFe and TiFe2 which decrease the joint strength more seriously than TiC. The interlayer in the S20C/Ti consisted of TiC as well as TiFe and TiFe2. The coexisting carbide and intermetallic compounds in the interlayer seems to have more detrimental effect on the joint strength than those formed individually.
