Mechancial Properties of Repaired 7075-T73 Friction Stir Weld Butt Welds
For production parts joined by friction stir welding, there is a need to identify the effects of rework in a shop environment, or later repair of damage in service, on mechanical properties. Effects on strength or microhardness have been previously characterized; however, often design loads may not be purely driven by static strength allowables, but instead by fatigue limits, which may be less sensitive to rework than ultimate or yield tensile strengths. To investigate those effects, defective butt welds were created in 0.25 in thick 7075-T73 Aluminum alloy plates. Welds were then repaired using similar parameters directly over the original weld. The mechanical properties of up to four passes after the initial weld were also investigated with a focus on fatigue life. An analysis of the results and a discussion of the implications for repair and rework of friction stir welded structures and assemblies are included.
Keywords7075 T-73 Friction stir processing Friction stir welding Welding defect Welding Repair
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- 1.‘Selection and Application of Aluminum Alloys.’ Aluminum and Aluminum Alloys. Ed. Joseph R. Davis. Materials Park, OH: ASM International, 1993. pp. 59–62.Google Scholar
- 2.Klsestrup Kristensen, J. et al. ‘Properties of Friction Stir Welded Joints in Aluminum Alloys 2024, 5083, 6082/6060 and 7075,’ 5th Intl. Friction Stir Welding Symposium, September, 2004.Google Scholar
- 3.Dalle Donne, C, Biallas, G., Ghindini, T., Raimbeaux, G., ‘Effect of Weld Imperfections and Residual Stresses on the Fatigue Crack Propagation in Friction Stir Welded Joints,’ Proceedings of the 2nd International Symposium on FSW, sponsored by TWI, Ltd., Gothenburg, Sweden, 26–28 June, 2000.Google Scholar
- 4.Tweedy, B., Allen, C, and Kumar, B., ‘Design, Analysis and Testing of Friction Stir Welded Thin Sheet 2024 and 7075 Aluminum Alloys,’ Aeromat Conference Presentation, Orlando, FL, 6–9 June, 2005.Google Scholar
- 5.C. Widener et. al, ‘Evaluation of Post-Weld Heat Treatments to Restore the Corrosion Resistance of Friction Stir Welded Aluminum Alloy 7075-T73 vs. 7075-T6,’ Materials Science Forum, vols. 539–543, 2007, pp. 3781–3788.Google Scholar
- 6.Lumsden, J., Pollock, G., and Mahoney, M., ‘The Effect of Thermal Treatments on the Corrosion Behavior of Friction Stir Welded 7050 and 7075 Aluminum Alloys,’ Materials Science Forum, vols. 426–432, 2003, pp. 2867–2872.Google Scholar
- 7.Reynolds, A.P., Lockwood, W.D., and Seidel, T.U., ‘Processing Property Correlation in Friction Stir Welds,’ Materials Science Forum, Vols. 331–337, 2000, pp. 1719–1724.Google Scholar
- 9.C. Widener, B. Tweedy, and D. Burford, ‘An Investigation of the Effects of Tool Design and Welding Parameters on Fatigue Life in Friction Stir Welded 2024-T3,’ 7th International Friction Stir Welding Symposium, Awaji Island, Japan, 20–22 May, 2008.Google Scholar
- 10.R. Brown, W. Tang, and A.P. Reynolds, ‘Multi-pass friction stir welding in alloy 7050-T7451: Effects on weld response variables and on weld properties,’ Materials Science and Engineering: A, Vols. 513–514, 15 July, 2009, Pages 115–121.Google Scholar