Formation process of the bonding joint in Ti/Al diffusion bonding

The process of the formation of Ti/Al diffusion bonding joints was studied by means of scanning electron microscopy (SEM), X-ray diffractometry (XRD) and shear strength measurement. Pure titanium and pure aluminum were used as bonding couples. The results show that the process of joint formation can be separated into four stages, and the product of the diffusion reaction is only TiAl3 under a particular range of holding time. There is a delay time tD before TiAl3 is generated, which is mainly affected by temperature. The joint strength depends on the metallurgical combination percentage and the interface structure in the diffusion zone, and it can reach or even exceed the strength of pure aluminum after TiAl3 forms a layer. The position where shear fracture occurs depends on interface structure in the diffusion zone.