POSTER
Issues in FSW of Aluminum Alloys to Steels and Main Solutions
By Mian Wasif Safeen (Faculty of Science and Technology, Free University of Bozen-Bolzano), Pasquale Russo Spena (Department of Management Engineering and Production, Politecnico di Torino)

Friction stir welding (FSW) is successfully employed in aeronautical and aerospace industries for joining aluminum parts. However, dissimilar FSW of aluminum with steel poses some issues, including the formation of Al/Fe intermetallic compounds (IMCs) and defects (e.g. tunnel, voids, cracks, surface grooves, flash), severe tool wear. All these factors have a detrimental effect on joint quality, mainly reducing mechanical strength under static and dynamic loading conditions. Al/Fe IMCs are brittle phases that usually form at elevated temperature at the Al-steel interface. They mainly promote nucleation of cracks in weld nugget. Tool wear is significant when joining aluminum with steel, thus having a direct effect in cost processing and formation of defects.
In the light of literature, the effects of the most important FSW parameters on the above mentioned issues and possible countermeasures are presented and discussed, including proper selection of process parameters, use of galvanized steel, coating of tools with wear-resistant materials, FSW assisted by laser heat source.