Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7952112 | Journal of Materials Science & Technology | 2018 | 12 Pages |
Abstract
7085-T7452 plates with a thickness of 12Â mm were welded by conventional single side and bobbin tool friction stir welding (SS-FSW and BB-FSW, respectively) at different welding parameters. The temperature distribution, microstructure evolution and mechanical properties of joints along the thickness direction were investigated, and digital image correlation (DIC) was utilized to evaluate quantitatively the deformation of different zones during tensile tests. The results indicated that heat-affected zone (HAZ), the local softening region, was responsible for the early plastic deformation and also the fracture location for SS-FSW samples, while a rapid fracture was observed in weld nugget zone (WNZ) before yield behavior for all BB-FSW specimens. The ultimate tensile strength (UTS) of SS-FSW joints presented the highest value of 410Â MPa, 82% of the base material, at a rotational speed of 300Â rpm and welding speed of 60Â mm/min, much higher than that of BB-FSW joints, with a joint efficiency of only 47%. This should be attributed to the Lazy S defect produced by a larger extent of heat input during the BB-FSW process. The whole joint exhibited a much higher elongation than the slices. Scanning electron microscopic (SEM) analysis of the fracture morphologies showed that joints failed through ductile fracture for SS-FSW and brittle fracture for BB-FSW.
Keywords
Related Topics
Physical Sciences and Engineering
Materials Science
Materials Chemistry
Authors
Weifeng Xu, Yuxuan Luo, Wei Zhang, Mingwang Fu,