Combined effect of pre-strain and ageing treatment on the tensile- shear strength behaviours of Al6082 aluminium alloys joined by clinching

Absztrakt

Clinching is the joining process in which two or more materials are joined by plastic deformation without the use of consumable parts. Therefore, it has no effect on the components’ weight. Nowadays, most vehicle industries use this technology. When joining Al6082 aluminium alloys in the as-received condition by clinching, the joint cannot be formed due to the material’s poor formability compared with other aluminium alloy series. Therefore, solution heat treatment (SHT) is performed on the sheet to increase the material’s ductility before joining. Additionally, a pre-strain is applied to the sheet before joining, since most car components are pre-strained during stamping, stretching, or forming processes, thereby introducing internal strain. Therefore, this study investigates the combined effect of pre-straining and post-clinching ageing on tensile-shear energy absorption and failure during the clinching of Al68082 sheet. The results show that as the post-clinching time increased, the joint’s tensile-shear and energy absorption increased. Additionally, the sheet’s pre-strain before joining affects joint strength. A fully neck-crack failure mode is observed in all combined effects. The study highlights that the combined effect of pre-strain and post-clinching ageing significantly affects the structural integrity of the clinched joint.