Fatigue Behavior of Friction Stir Welded EN AW 5754 Aluminum Alloy Using Load Increase Procedure
Friction stir welding (FSW) is an advantageous method in the thermal joining processes, featuring the welding of various dissimilar and similar material combinations, joining temperatures below the melting point which prevents irregularities such as pores and hot cracks as well as high strengths mechanical joints near the base material. The FSW process consists of a rotating tool which is made of a shoulder and a probe. The welding process is based on a rotating tool which plunges in the workpiece under axial pressure. As a result, the material is plasticized by frictional heat which leads to a decrease in the flow stress. During the welding procedure, the material is continuously displaced by the tool, creating a firmly bonded weld seam behind the tool. However, the mechanical properties of the weld seam are affected by the design and geometry of the tool. These include in particular microstructural and surface properties which can favor crack initiation. Following investigation compares the dynamic properties of FSW weld seams with conventional and stationary shoulder geometry based on load increase test (LIT). Compared to classical Woehler tests, it is possible to determine the fatigue strength of the specimens after a short amount of time. The investigations were carried out on a robotized welding setup on 2 mm thick EN AW 5754 aluminum alloy sheets. It was shown that an increased tensile and fatigue strength can be achieved by using the stationary shoulder concept. Furthermore, it could be demonstrated that the LIT is a valid method to describe the fatigue behavior of FSW weld seams.
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 W. M. Thomas et al., “Improvements Relating to Friction Welding,” Patent WO 9310935, 1992.
 M. Gutensohn, G. Wagner, F. Walther, D. Eifler, “The Fatigue Behaviour of Friction Stir Welded Aluminium Joints,” Welding in the World, vol. 52, no. 9-10, pp. 69–74, Sep. 2008.
 W. M. Thomas, E. D. Nicholas, “Friction Stir Welding for the Transportation Industries,” Materials & Design, vol. 18, no. 4-6, pp. 269–273, Dec. 1997.
 S. W. Kallee, J. M. Kell, W. M. Thomas, C. S. Wiesner, “Development and Implementation of Innovative Joining Processes in the Automotive Industry,” DVS Annual Welding Conf., Essen, 2005.
 R. B. Aronson, “A New Look at Aircraft Assembly,” Manufacturing engineering, vol. 132, no. 3, pp. 101–108, 2004.
 J. Schneider, R. Beshears, A. C. Nunes, “Interfacial Sticking and Slipping in the Friction Stir Process,” Materials Science and Engineering. A, vol. 435-436, pp. 297–304, Nov. 2006.
 IIW International Institute of Welding, (2011). DIN EN ISO 25239-1: Friction Stir Welding - Aluminium - Part 1: Vocabulary.
 M. Haghshenas et al., “Friction Stir Weld Assisted Diffusion Bonding of 5754 Aluminum Alloy to Coated High Strength Steels,” Materials & Design, vol. 55, pp. 442–449, Mar. 2014.
 M. I. Costa, D. Verdera, C. Leitão, D. M. Rodrigues, “Dissimilar Friction Stir Lap Welding of AA 5754-H22/AA 6082-T6 Aluminium Alloys: Influence of Material Properties and Tool Geometry on Weld Strength,” Materials & Design, vol. 87, pp. 721–731, Dec. 2015.
 H. Badarinarayan, Y. Shi, X. Li, K. Okamoto, “Effect of Tool Geometry on Hook Formation and Static Strength of Friction Stir Spot Welded Aluminum 5754-O Sheets,” International Journal of Machine Tools and Manufacture, vol. 49, no. 11, pp. 814–823, Sep. 2009.
 V. -X. Tran, J. Pan, T. Pan, “Effects of Processing Time on Strengths and Failure Modes of Dissimilar Spot Friction Welds Between Aluminum 5754-O and 7075-T6 Sheets,” Journal of Materials Processing Technology, vol. 209, no. 8, pp. 3724–3739, Apr. 2009.
 A. Macwan, D. L. Chen, “Ultrasonic Spot Welding of Rare-Earth Containing ZEK100 Magnesium Alloy to 5754 Aluminum Alloy,” Materials Science and Engineering: A, vol. 666, pp. 139–148, June. 2016.
 S. H. Chowdhury, D. L. Chen, S. D. Bhole, X. Cao, P. Wanjara, “Lap Shear Strength and Fatigue Life of Friction Stir Spot Welded AZ31 Magnesium and 5754 Aluminum Alloys,” Materials Science and Engineering: A, vol. 556, pp. 500–509, Oct. 2012.
 V. -X. Tran, J. Pan, T. Pan, “Fatigue Behavior of Spot Friction Welds in Lap-Shear and Cross-Tension Specimens of Dissimilar Aluminum Sheets,” International Journal of Fatigue, vol. 32, no. 7, pp. 1022–1041, July. 2010.
 V. -X. Tran, J. Pan, T. Pan, “Fatigue Behavior of Aluminum 5754-O and 6111-T4 Spot Friction Welds in Lap-Shear Specimens,” International Journal of Fatigue, vol. 30, no. 12, pp. 2175–2190, Dec. 2008.
 M. Gutensohn, G. Wagner, F. Walther, D. Eifler, “Cyclic Deformation Behavior of Friction Stir Welded (FSW) Aluminum Joints,” in Proc. 11th International Conference on Aluminium Alloys, Aachen, 2008.
 German National Standard, (2009). DIN EN 573-3, Aluminium and Aluminium Alloys - Chemical Composition and Form of Wrought Products - Part 3: Chemical Composition and Form of Products.
 IIW International Institute of Welding, (2011). ISO 25239-5, Friction Stir Welding - Aluminium - Part 5: Quality and Inspection Requirements.
 German National Standard, (2016). DIN 50125: Testing of Metallic Materials - Tensile Test Pieces.
 International Organization for Standardization, (2016). ISO 6892-1, Metallic Materials - Tensile Testing - Part 1: Method of Test at Room Temperature.
 F. Walther, W. Eifler, “Cyclic Deformation Behavior of Steels and Light-Metal Alloys,” Materials Science and Engineering. A, vol. 468-470, pp. 259–266, Nov. 2007.
 F. Walther, “Microstructure-Oriented Fatigue Assessment of Construction Materials and Joints Using Short-Time Load Increase Procedure,” Materials Testing, vol. 56, no. 7-8, pp. 519–527, 2014.
 A. Schmiedt, S. Jaquet, M. Manka, W. Tillmann, F. Walther, “Tensile and Fatigue Assessments of Brazed Stainless Steel Joints Using Digital Image Correlation,” in 2018 MATEC Web of Conf., vol. 165, pp. 8.
 H. Halim, D. S. Wilkinson, M. Niewczas, “The Portevin-Le Chatelier (PLC) Effect and Shear Band Formation in an AA5754 Alloy,” Acta Materialia, vol. 55, pp. 4151–4160, May. 2007.