Mechanical Behaviour of Al-Li Alloy Joints by Different Friction Stir Welding Parameters

Abstract:

In this study, the Al-Li alloy plates were friction stir welded (FSW) at different welding parameters, and the effect of welding parameters on the hardness, tensile and fatigue properties of the butted and lapped FSWed joints were investigated. The experimental results showed that the ultimate strength and elongation of butted joints decreased as the heat input increasing, and the maximum ultimate strength of the joints was equivalent to 83% that of the base material. By comparison of the heat inputs during welding process at different parameter combinations, the relationship between the microstructure and mechanical property of FSWed joints was established. For the overlapped welds made in 2mm thick plates of Al-Li-S4 and 2099 alloys, the hooking defect was a typical and inevitable defect appearing on the TMAZ of both advancing and retreating sides, which would adversely damage the mechanical properties of overlapped joints. Furthermore, the length of pin significantly affected the tensile property of overlapped joints, when the length of pin varies from 2.8mm to 2.5mm, the ultimate strength increased 14% to 20%. In addition, the fatigue lifetime of overlapped joints was lower than that of butted joints and base metal.

• Periodical: Advanced Materials Research (Volume 1051)
• Pages: 799-807
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.1051.799
• Online since: October 2014
• Authors: Dan Dan Zhang*, Wen Qing Qu, Qun Bo Lv, Yang Yang Liu, Wei Yan Li, Xin Wen Chen
• Keywords: Al-Li Alloy, Friction Stir Weld, Mechanical Property, Microstructure, Welding Parameter

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