Effect of root flaws on the fatigue property of friction stir welds in 2024-T3 aluminum alloys

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Vol. 418; no. 1; pp. 155 - 160
• Main Authors: Zhou, Caizhi, Yang, Xinqi, Luan, Guohong
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 25-02-2006; Elsevier
• Subjects: Applied sciences; Exact sciences and technology; Fatigue; Fatigue performance; Friction stir welding; Joining, thermal cutting: metallurgical aspects; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Metals. Metallurgy; Microstructure; Root flaws; Welding; Root flaws; Microstructure; Friction stir welding; Fatigue performance; Fatigue life; Welded joint; Fatigue strength; Butt joint; Defect; Fatigue; Aluminium alloy; Welding parameter
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2005.11.042

The fatigue experiment of friction stir (FS) welds in 2024-T3 aluminum alloys were performed to investigate the influence of root flaws on the fatigue strength and life of FS welds. The test results of welds with flaws (flawed welds) were compared with the results suggested by the International Institute of Welding (IIW) recommendations and the welds without root flaws (flaw-free) in the published research reports. It was found that there was always existed flaws at the roots of FS welds because of unsuitable welding parameters and the vertical length of the flaws is about 0.31–0.33
mm for the FS butt-welded joint of 4
mm in thickness. The fatigue life of flawed welds is 33–80 times shorter than that of flaw-free welds, and the fatigue characteristic values have decreased from 120.6
MPa for flaw-free welds to 54.7
MPa for flawed welds at 2
×
10
6 cycles.