Microstructure, mechanical properties and corrosion resistance of friction stir welded joint of Al-Mg-Mn-Zr-Er alloy

The microstructure, mechanical properties and corrosion resistance of friction stir welded joint of Al-Mg-Mn-Zr-Er alloy were investigated under three FSW parameter sets: 800 rpm x 100 mm min(-1), 800 rpm x 80 mm min(-1) and 600 rpm x 80 mm min(-1). The microstructural transformation sequence of welded joint is discontinuous dynamic recrystallization, dislocation introduction, dynamic recovery and continuous dynamic recrystallization. The mechanical properties of welded joint are highly correlated with the welding process parameters. The welded joint can obtain good tensile strength and elongation under the parameters of 800 rpm x 100 mm min(-1). Corrosion resistance of welded joints has little correlation with welding parameters, but is mainly related to different positions of welded joints. The main influencing factor is grain structure state. The intergranular corrosion susceptibility is related to beta(Al3Mg2) phase.