MECHANICAL PROPERTIES OF FRICTION STIR-WELDED JOINTS OF ALUMINUM ALLOYS

Mechanical properties, intergranular corrosion, and a chemical composition of the welded joint, produced with friction stir welding of a 6061T651 aluminum alloy were investigated. The results show that the welded seam is uniform, with a smooth surface. There are no deformation and defects, such as cracks or gas-filled porosity. The average tensile strength of welded joints is 73% of that of the base material, while the average yield strength and elongation are only 54 and 43% of those of the base material. After intergranular corrosion, microhardness changes evidently and corrosion resistance is lower in the root of the weld nugget zone. The change in microhardness is not pronounced in the weld nugget zone and welded surface, but the change in microhardness is well-pronounced and corrosion resistance is lower in the thermomechanically- and heat-affected zones.