Mechanical properties and microstructural characteristics of refill friction stir spot welded thin aluminum alloys
By Fan Cui (Shanghai Aerospace Equipments Manufacturer), Murilo Santos (Helmholtz-Zentrum Geesthacht GmbH), Junjun Shen (Helmholtz-Zentrum Geesthacht GmbH), Xuecheng Song (Shanghai Aerospace Equipments Manufacturer), Lijie Guo (Shanghai Aerospace Equipments Manufacturer), Jorge Dos Santos (Helmholtz-Zentrum Geesthacht GmbH)

Refill Friction Spot Welding is a promising solid-state spot welding process, which can be an alternative to replace the current riveting process in aerospace applications. This research is to study the refill friction spot weldability and the resultant mechanical properties of a 0.8 mm-thick to a 3.0 mm-thick alclad aluminum alloy 2A12. In order to optimize the welding process, a Response Surface Methodology was employed. The lap-shear test shows that the strength level of AA2A12 welds fullfils the desired technical specifications and the AWS specification of resistance spot welded alumnum alloys. The representative weld microstructure as well as alclad is investigated by means of light microscopy and EBSD (electron back-scatter diffraction).