Solid state diffusion bonding of titanium to steel using a copper base alloy as interlayer

Dissimilar titanium/steel metals were successfully joined by diffusion bonding process with the help of a copper-based interlayer. The appropriate processing parameters have been investigated and the joints were analyzed by means of scanning electron microscopy (SEM), microhardness measurement, shear strength test, and X-ray diffractometry (XRD). The results show that the joint could not be bonded at a temperature lower than 800 °C even at holding time of 180 min. However, at 850 °C successful joining was achieved at all holding times. On the other hand, atom diffusion and migration between Ti and Fe or C were effectively prevented by adding a copper-based interlayer and hence, Fe–Ti and Ti–C intermetallics were not formed in the joint. This technique provides a reliable method of bonding titanium to steel.