Understanding tool-workpiece interfacial friction in friction stir welding/processing and its effect on weld formation

Friction Stir Welding and Processing (FSW/P) is a solid-state joining and/or processing technique largely used for aluminium and its alloys. Although the process matured over a period, there is ambiguity over quantification of frictional values at tool-workpiece interface. Such data are crucial in Finite Element (FE) modelling of the process and understanding the frictional boundary condition plays a crucial role in its development. The paper discusses quantification of frictional boundary condition and its impact on weld formation. The evaluation suggested the necessity of stick conditions for weld consolidation and its mandatory occurrence during the process. Simulations performed with m = 1 yielded temperature results closer to experiments and facilitated in closure of void.