Performance enhancement of clinched joints with ultrasonic welding for similar and dissimilar sheet metals

The clinching technology is a joining method that uses interlocking structures for the fastening. The mechanical properties of the process are limited by the strength of material. This study proposes a method of combined clinched joints with ultrasonic welding to improve the strength and mechanical properties of the structures. The TA1 titanium alloy and 5A06 aluminum alloy plate were chosen to produce titanium-aluminum homogeneous or heterogeneous clinched joints and ultrasonic clinched joints. The tensile shear tests were performed to study the mechanical properties and failure modes of the joints. The main forms of joint failure were further analyzed in detail by observing the microscopic morphology of the joint, and the effects of ultrasonic welding on the joint were discussed. The results showed that the mechanical properties of the ultrasonic clinched joints were substantially improved compared to those of the conventional clinched joints. The UCAA joints (ultrasonic clinched aluminum-aluminum joints) showed a 196.8% increase in average peak load and a 208.42% increase in average failure displacement. Likewise, the UCAT joints (ultrasonic clinched aluminum-titanium Joints) indicated a 180.9% increase in peak load and a 252.12% increase in the average failure displacement value. The mechanical properties of UCTT joints (ultrasonic clinched titanium-titanium joints) and UCTA joints (ultrasonic clinched titanium-aluminum joints) have also been improved to varying degrees. The ultrasonic clinched joints are effective to be processed in welding for aircraft and spacecraft application.