Clinch joining of heat-treatable aluminum AA6082-T6 alloy under warm conditions

•Mechanical clinching was performed on AA6082T6 sheets with reduced ductility.•Pre-heating was adopted to avoid crack development either increase mechanical behaviors.•The mechanical behaviors of joints were investigated by single lap shear joints.•The influence of process parameters mechanical behaviors were assessed. The mechanical behavior of clinched joints is highly influenced by the material flow produced during the joining operations. In order to achieve stronger joints, the geometry of clinching tools is generally varied. The present investigation is aimed at analysing how the material flow can be controlled through the concurrent employment of pre-heating and tools geometry modifications. To this end, thin sheets made of heat-treatable aluminum alloy AA6082-T6 were joined by mechanical clinching using extensible dies. The joining force, clinching tools and pre-heating conditions were varied. The influence of process conditions on material flow and mechanical behavior of clinched connections was investigated. Metallurgical analysis was performed to investigate how heating conditions affects the material structure. According to the achieved results, the employment of opportune pre-heating conditions allows avoiding fractures, improving the material flow and consequently enhancing the mechanical behaviour of clinched connections.