The influence of welding parameters on macrostructure and mechanical properties of Sc-modified AA2519-T62 FSW joints

Abstract

In this investigation, a 5 mm thick extrusion of AA2519-T62 alloy has been welded using friction stir welding method. The various sets of process parameters have been involved within the range of 400-1200 rpm tool rotation speed and 100-800 mm/min welding speed. Selected joints have been subjected to the macrostructure analysis, microhardness measurements, tensile and low cycle fatigue testing (at ϵ = 0.3%), and fractography analysis. It has been stated that imperfection-free macrostructure is obtained for welds produced with lowest welding speed: 100 mm/min and tool rotation speed within the range of 400-800 rpm. The highest joint efficiency (85%) has been obtained for the sample characterized by the presence of voids in the upper part of the stir zone. Considering macrostructure analysis and established mechanical properties of the joints, it may be concluded that the best set of welding parameters for AA2519-T62 is within the range of 600-800 rpm tool rotation speed with welding speed of 100 mm/min for used MX Triflute tool.