Strengthening mechanism in the dissimilar CpTi/Inconel 718 joints obtained through diffusion bonding.

The lap joints of the CpTi/Inconel-718 was obtained by Diffusion bonding (DB) at 1020 degrees C for 1.5 h. Microstructure and chemical composition of the lap joints were examined using polarizing Microscope, Scanning Electron Microscope(SEM) and X-Ray Diffraction(XRD). The region of the CpTi in the vicinity of interface was transformed into ll-Ti and after to that was a region observed as a-Ti Widmanstatten needles in a matrix of ll-Ti. This transformation of CpTi into ll-structure in the vicinity of the interface was attributed to the diffusion of ll-stabilizers from the Inconel side of the joint. The average shear strength of the DB CpTi/Inconel-718 joints was measured to be 223 MPa which was greater than the conventional Pulsed TIG (P-TIG) weldment of CpTi/Inconel718 obtained using the V and Nb interlayers. This was attributed to the stabilization of ll-Ti as well as confinement of IMCs to a thinner region in the DB CpTi/Inconel-718 joints.

Automated summary

The lap joints of CpTi/Inconel-718 were obtained using diffusion bonding at 1020°C for 1.5 hours. Microstructural and chemical composition analysis revealed that the CpTi region near the interface transformed into ll-Ti and subsequently exhibited a region of a-Ti Widmanstatten needles in a matrix of ll-Ti. This transformation was attributed to the diffusion of ll-stabilizers from the Inconel side. The average shear strength of the DB CpTi/Inconel-718 joints was measured to be 223 MPa, higher than the conventional Pulsed TIG weldment of CpTi/Inconel-718 using interlayers.