Influence of tool rotational speed on the evolution of microstructure and mechanical properties of precipitation-hardened Aluminium 6061 butt joint during friction stir welding

Abstract The present investigation intends to interpret the effect of tool rotational speed on mechanical properties and microstructural evolution in Aluminium 6061-T6 alloy during friction stir welding. A higher value rotation produces more hardness at nugget zone, which is attributed intensity reprecipitation rpm, revealed by transmission electron microscopy. zone as a nearly precipitate-free region, while thermo-mechanically affected contains coarse precipitates, deformed dynamically recovered grains with few recrystallized grains. Significant reduction grain size stirred also key finding. observations depict dependence microstructure, thus behaviour speed. specific combination process parameters has been determined from experiments, corresponds maximum joint efficiency.