Tensile properties of a friction stir welded thin-sheet of 1050-H24 aluminum alloy

Friction stir welding (FSW) is a promising welding process that can produce low cost and high quality joints with aluminum alloys. To examine the friction stir weldability of a 3 mm thick 1050-H24 aluminum alloy sheet, joint tensile properties and fracture locations in the Joints have been studied. The experimental results show that FSW clearly softens the aluminum alloy sheet; thus, the tensile properties of FSW Joints are lower than those of the base material, and the ultimate strength of the joints is only 70% that of the base material. The FSW parameters do not significantly affect the tensile properties of the joints, thus the range of the welding parameters that can be used to form a Joint is comparatively wide. However, the welding parameters influence the fracture locations in the joints. When the revolutionary pitch (RP) is smaller than a critical value, the joints fracture on the retreating side (RS) of the weld. When the RP is greater than the critical value, a lack-of-penetration root defect is formed in the Joints, and the joints fracture in the weld center.