Influence of rivet on process and failure behavior of self-piercing riveting in dissimilar sheets of TA1 and 1420 Al-Li alloys

Using self-piercing riveting (SPR), riveting processes of dissimilar sheet combinations in TA1 titanium and 1420 aluminum lithium alloy sheets were analyzed with different rivets in detail. And SPR joints of TA1-1420 (TAF), 1420-TA1 (ATF) and TA1-1420 (TAS) were fabricated from different rivets with length of 6 mm and hardness of 44 HRC ±2 HRC and 48 HRC ±2 HRC, correspondingly. Through tensile-shear tests and fatigue tests, failure modes of three groups of joints were obtained. Furthermore, influences of rivet on failure behaviors of self-piercing riveting dissimilar sheets in TA1 and 1420 aluminum lithium alloys were analyzed using electron scanning microscope (SEM). Results show that:rivets have a significant influence on riveting processes of dissimilar sheet combinations. And they can be effectively connected with the rivets of proper length. The upsetting degree can be reduced with the hardness of rivets increased. As the hardness of rivets increased, the failure parts are changed from the huge deformation area to the bottom of the joint and the hardness of rivets also have a significant influence on the failure behaviors of these joints.