Interface characteristics and joining mechanism of TC4 titanium alloy/6061 aluminium alloy vacuum diffusion joining joint

Vacuum diffusion joining technology was employed to join TC4 titanium alloy and 6061 aluminium alloy. The impacts of joining temperature and time on the interface features and mechanical traits of Ti/Al diffusion joints were thoroughly investigated. The Ti/Al joint interface mainly consists of a diffusion-reaction layer with the TiAl₃ phase. As the joining temperature increases and the duration lengthens, the thickness of the diffusion-reaction layer gradually grows. The growth kinetic model for the diffusion reaction layer was formulated through the calculation of interface kinetic parameters. At 550 °C for 2 hours, the joint's maximum tensile strength reached 133 MPa, which is significantly higher than that of Ti/Al joints made by other comparable welding processes. XRD analysis of the fracture surface verified that the fracture took place at the TiAl₃/Al interface. When temperature and pressure team up, they bring about four different stages at the Ti/Al joint: first, there is initial physical contact, then atomic diffusion kicks in, followed by an interfacial reaction, and finally, phase formation. All in all, these processes lead to a top-notch metallurgical bond. The results of this research offer a dependable experimental foundation for the secure and steady operation of crucial Ti/Al components in aeroplanes.