| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 830235 | Materials & Design (1980-2015) | 2013 | 7 Pages |
Reverse dual-rotation friction stir welding (RDR-FSW) has great potential to obtain appropriate welding conditions through adjusting the independently rotating tool pin and surrounding shoulder. The welding torque exerted on the workpiece by the reversely rotating shoulder also cancels off a part of the welding torque exerted by the rotating tool pin, thus the clamping requirement for the workpiece is also reduced. In the present paper, a tool system for the RDR-FSW was designed and successfully applied to weld high strength aluminum alloy 2219-T6, and then microstructures and mechanical properties of the optimized joint were investigated to demonstrate the RDR-FSW characteristics. The weld nugget zone was characterized by the homogeneity of refined grain structures, but there was a three-phase confluction on the advancing side formed by different grain structures from three different zones. The tensile strength of the optimized joint was 328 MPa (73.7% of the base material), showing an obvious improvement when compared with the optimized joint welded by the FSW without the reversely rotating assisted shoulder. The tensile fracture occurred in the ductile fracture mode and the fracture path propagated in the weakest region where the Vickers hardness is the minimum.
► The reverse dual-rotation FSW is proposed to reduce clamping requirements of workpieces. ► A tool system for the dual-rotation FSW is designed and utilized to weld AA2219-T6. ► There is a three-phase confluction on the AS formed by the SAZ, TMAZ and WNZ. ► Tensile properties of the optimized joint gain an improvement, especially elongation. ► The tensile fracture propagates in different zones at the upper and lower part.
