Joining Aluminum with Titanium alloy sheets by mechanical clinching

The feasibility of titanium aluminum hybrid joints is investigated. Titanium grade 2 was coupled with different aluminum alloys of 5xxx, 6xxx and 7xxx series. The joining process was performed by means of a clinching machine at room temperature using extensible dies. Different joining forces and tools configurations were adopted. The material flow was investigated by means of experimental observations of cross sections. A numerical model of the joining process was also developed to study how the material flow develops. Single lap shear tests were performed to determine the mechanical behavior of the joints. The results highlighted a narrow join-ability window. Only aluminum AA7075 was capable to be joined to titanium sheets. The other alloys were susceptible of different material flow issues e.g. fracture development or no interlock formation that yielded to unsuccessful joining conditions.