Recycling of scrap sheet material: Enhanced joining mechanical properties of aluminum alloys by a novel auxiliary sheet flat-clinching process

Recently, lightweight aluminum alloy materials are widely used in fields such as automobiles, construction and aerospace. The joining of aluminum alloys and the green disposal of the inevitable scrap sheet material has attracted much attention. In this paper, a novel strategy is proposed for recycling scrap aluminum alloy materials as auxiliary sheets to improve the mechanical properties and reduce the joint bulge height, which is auxiliary sheet flat-clinching process. Meanwhile, the forming mechanism and failure evolution of joints were investigated, and the reasons for the auxiliary materials to increase the strength of the joints were analyzed. In addition, the influence law of different auxiliary sheet materials (AL5052-H32, AL5182-O and AL6061-T6) on the mechanical properties was revealed. From the experimental results, the auxiliary sheet flat-clinching process improves the mechanical properties of the joint caused by increasing the neck thickness. The greater the deformation resistance of the auxiliary sheet materials, the larger the interlock value, neck thickness and bottom thickness of the joint, and the smaller the bulge height. As a result, the AL6061 auxiliary sheet flat-clinching joint exhibits the best mechanical properties. Compared to ordinary flat-clinching joints, it increases energy absorption, tensile shear load and stiffness by 140%, 42% and 26%, respectively.(c) 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).