Investigation of the Impact of Tool Pin Geometry and Feed Rate Speed in Friction Stir Lap Welding of 7075 and 5182 Aluminum Alloys

Abstract

7075 and 5182 aluminum alloys are crucial for aerospace and automotive applications, receptively. Joining these alloys can enable more economical and efficient structures. Therefore, weldability of these materials by friction stir lap welding (FSLW) was studied based on investigating influence of tool pin geometry (conical and cylindrical screw) and welding speed (22, 37 and 51 mm min-1) on weld microstructure and mechanical properties. Strong welds were acquired with both tools. However, stronger ones were made employing conical pin tool thanks to having a deeper weld penetration and denser microstructure. Weld strength improved with increasing tool advancing speed for conical pin tool since welded area width and vertical downward penetration increased while opposite of this occurred for cylindrical screw pin. While by conical pin, the strongest weld having 13033 N tensile load was made at 51 mm min-1, by cylindrical screw pin, the strongest weld with 12162 N was obtained at 22 mm min-1. It was an indication of a stronger weld formation for both tools when the lines formed through tool shoulder on top surface of upper sheet were broken into small particles and disappeared. Proper tool advancing speed value can show considerable variability depending on tool pin geometry.

Keywords

• Friction stir lap welding
• aluminum alloys
• tool pin geometry
• macro and microstructure
• tensile load capacity
• fracture

References

1. Christner B, Mc Coury J, Higgins S. Development and testing of friction stir welding as a joining method for primary aircraft structure. In: 4th International symposium on friction stir welding, Park City, Utah, USA, May 14-16, TWI Ltd. 2003.
2. Das A, Butterworth I, Masters I, Williams D. Microstructure and mechanical properties of gap-bridged remote laser welded (RLW) automotive grade AA 5182 joints. Materials Characterization. 2018;145:697-712.
3. Gibson BT, Lammlein DH, Prater TJ, Longhurst WR, Cox CD, Ballun MC, Dharmaraj KJ, Cook GE, Strauss AM. Friction stir welding: Process, automation, and control. Journal of Manufacturing Processes. 2014;16(1):56-73.
4. Xie S, Xia Z, Ding R, Li H, Bowen P. Microstructure and mechanical properties of two Al alloys welded by linear friction weld. Materials Science and Engineering A. 2021; 816:141261.
5. Caligulu U, Acik M, Balalan Z, and Kati N. The Effects of Process Parameters for Joining of AISI 1010-Cu Alloys by Friction Welded. International Journal of Steel Structures. 2021;15(4):923-931.
6. Kumar N, Yuan W, Mishra RS. Friction Stir Welding of Dissimilar Alloys and Materials. Elsevier, Oxford, 2015.
7. Abdollah-Zadeh A, Saeid T, Sazgari B. Microstructural and mechanical properties of friction stir welded aluminum/copper lap joints. Journal of Alloys and Compounds. 2008;460(1-2): 535-538.
8. Leal RM, Loureiro A. Effect of overlapping friction stir welding passes in the quality of welds of aluminium alloys. Materials & Design.2008; 29(5):982-991.Hasund IK. The discourse markers like in English and liksom in Norwegian teenage language : A corpus-based, cross-linguistic study [dissertation]. Bergen: University of Bergen; 2003.

9. Balasubramanian V. Relationship between base metal properties and friction stir welding process parameters. Materials Science and Engineering A. 2008;480(1-2):397-403.
10. Buffa G, Campanile G, Fratini L, Prisco A. Friction stir welding of lap joints: influence of process parameters on the metallurgical and mechanical properties. Materials Science and Engineering A. 2009;519(1-2):19-26.
11. Bahemmat P, Rahbari A, Haghpanahi M, Besharati MK. Experimental study on the effect of rotational speed and tool pin profile on AA2024 aluminum friction stir welded butt joints. In: Proceedings of ECTC ASME early career technical conference. Miami, Florida, USA. 2008. p. 11-17.
12. Çevik B, Özçatalbaş Y, Gülenç B. Effect of tool material on microstructure and mechanical properties in friction stir welding. Materials Testing. 2016;58:36-42.
13. İş EG, Koçak K, Basar ZS, Yavuz Y, Topuz P. Effects of different profiled pins used in friction stir welding of Al 6061 T6. Materials Testing. 2023;65:1474-1481.
14. Cakan A, Ugurlu M, Kaygusuz E. Effect of weld parameters on the microstructure and mechanical properties of dissimilar friction stir joints between pure copper and the aluminum alloy AA7075-T6. Materials Testing. 2019;61:142-148.
15. Thomas WM, Norris IM, Stains DG, Watts ER. Friction stir welding-process developments and variant techniques. Oconomowoc, Milwaukee: The SME summit; 2005. p. 1-21.
16. Lee CY, Lee WB, Kim JW, Choi DH, Yeon YM, Jung SB. Lap joint properties of FSWed dissimilar formed 5052 Al and 6061 Al alloys with different thickness. Journal of Materials Science. 2008;43:3296-304.
17. AWS D17.3/D17.3M:2010. Specification for Friction Stir Welding of Aluminum Alloys for Aerospace Applications. American Welding Society (AWS). Miami, Florida (USA); 2009.
18. Threadgill PL, Leonard AJ, Shercliff HR, Withers PJ. Friction stir welding ofaluminium alloys. International Materials Reviews. 2009;54(2):49-93.
19. Song Y, Yang X, Cui L, Hou X, Shen Z, Xu Y. Defect features and mechanical properties of friction stir lap welded dissimilar AA2024–AA7075 aluminum alloy sheets. Materials and Design. 2014;55:9-18.
20. Bayazid SM, Farhangi H, Asgharzadeh H, Radan L, Ghahramani A, Mirhaji A. Effect of cyclic solution treatment on microstructure and mechanical properties of friction stir welded 7075 Al alloy. Materials Science and Engineering A. 2016;649:293-300.
21. Kaplan M, İleriturk M & Balalan Z. Relationship Between Microstructure, Hardness, XRD, TGDTA Analysis, and Wear Performance of a Cast ZA Alloy. Materials and Manufacturing Processes. 2008;23:400-406.
22. Cetkina E, Çelika YH, Temiz S. Microstructure and mechanical properties of AA7075/AA5182 jointed by FSW. Journal of Materials Processing Technology. 2019;268:107-116.
23. Çetkin E., Kılıçkap E., Çelik YH. Investigation of the Effects of Welding Force, Vibration and Temperature on Mechanical Properties and Microstructure in FSW Welding. Journal of Polytechnic. 2023;26:(1)445-455.
24. Xie H, Chen X, Lu Y, Zhang M, Zhang Q. Forming mechanism and mechanical properties of dissimilar friction stir lap welds of 304 austenitic stainless steel to a Ti6Al4V alloy. Materials Testing. 2021; 63:889-894.
25. Cetkin E., Çelik YH & Kilickap E. Effect of Temperature, Force, and Vibration on Fatigue Strength of Friction Stir-Welded AA7075 Aluminum Alloy Joints. Journal of Materials Engineering and Performance. 2021;30:202-211.