TWI

Friction stir welding (FSW) experiments on aluminium alloys were conducted using transparent PVC material to visualise dynamic material flow by direct observation, and the characteristics of two types of vortex were investigated. A single block of PVC (thickness 38 mm) was used as the workpiece. The process conditions included a tool angle of 3 degrees, a rotational speed of 750 rpm and travel speed of 1.5 mm/s. A high speed video recorder was employed to observe material flow during FSW. Threading direction effects were taken into account by studying both right hand and left hand screw probes. The circular speed of vertical and horizontal vortices was estimated. The formation mechanism of asymmetric weld metal cross-sections and onion rings is discussed.

7th International Symposium, 20-22 May 2008, 7B: Microstructure 2, Paper 03