Effect of Reverse-threaded Pin on Mechanical Properties of Friction Stir Lap Welded Alclad 2024 Aluminum Alloy

Yumei Yue¹，Zhengwei Li¹，Shude Ji^1,2，Yongxian Huang²，Zhenlu Zhou¹

1. Faculty of Aerospace Engineering, Shenyang Aerospace University2. State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology

摘 要：In friction stir welding（FSW）, tool geometry plays an important role in joint quality. In order to improve mechanical properties of friction stir lap welding（FSLW） joint, a tool with a reverse-threaded pin was designed in the present study. Using 2024-T4 aluminum alloy as the research object, tools with the fullthreaded pin and reverse-threaded pin were used in FSLW. Results showed that, when using the same parameter combination, FSLW joint using the reverse-threaded pin owned bigger effective sheet thickness（EST）, bigger lap width and better lap shear failure strength. Compared with the full-threaded pin,fracture mode of the FSLW joint changed from shear fracture mode to tensile fracture mode when the reverse-threaded pin was used. Fracture morphologies presented ductile fracture.

关键词：