Experimental investigation of the joinability of three-layer aluminum/ polymer/ aluminum composite sheets by the clinching process

Three-layer aluminum/polymer/aluminum laminate sheets are one of the new materials used to decrease the weight and air pollution of vehicles. Using the conventional methods for joining these sheets have lots of challenges. In this paper, the jointability of the three-layer aluminum/polymer/aluminum to a single-layer 1-mm-thick aluminum sheet is investigated, using the clinching process, which is a joining by forming process. The three-layer aluminum/polymer/aluminum sheets are prepared under laboratory conditions using the aluminum 5754 and in 0.5/0.6/0.5 thickness arrangement. The effect of the pin penetration depth and pin conical angle on the joint properties is investigated. The joint cross-section is considered to compare the neck thickness and interlock in different joining conditions. Also, the joints’ strength is investigated using shear and peel tests. The results indicate that increasing the pin penetration depth to an optimum value, improves the interlock and joint strength. Additionally, the strength of the joint created by the straight pin is higher than that of the 3deg conical pin, in the same pin penetration depth. In all test conditions, the best joining conditions happened when the failure mode was a combination of the bottom separation and neck fracture.