The Influence of Tool Geometry for Refill Friction Stir Spot Welding (RFSSW) on Weld Properties During Joining Thin Sheets of Aluminum Alloys

1. Financial support of The National Centre for Research and Development, European Union, PZL Mielec / a Sikorsky Company, in the framework of European Regional Development Fund Project “Advanced techniques for the fabrication of airframe structures using innovative friction stir welding (FSW) technology”, no. INNOLOT/I/4/NCBR/2013 is gratefully acknowledged.