Vorticity field analysis of friction stir welding: a new perspective for material flow and its implications

The paper demonstrates a new description of the Friction Stir Welding (FSW) process by the vorticity field analysis of the plasticised materials in the vicinity of the tool and workpiece interface. The study emphasised the implications of different metallurgical aspects in the vorticity field perspective. The analysis manifested the deformation and flow behaviour of grains towards the centre and in the downward directions. The maximum value of the vorticity field magnitude in FSW of AA5083 was observed to be about 4450 s⁻¹ near the edge of the pin bottom region. The evolution of onion rings was also postulated using the vorticity field.