Stepwise double-sided friction stir welding: an alternative for root defect mitigation in aluminium plates with lower gauge numbers

Abstract

Penetration-induced fractional unbonded defects and flow-induced root flaws are part of the discontinuities of the conventional friction stir welded (FSW’ed) aluminium alloys with limited impact assessment/clarification in literature. The novelty of this study lies in the attempt to eliminate penetration-aided root defect via a stepwise double-sided welding process as well as identify its impact on loadbearing. As a result, the stepwise double-sided FSW welding of a thick aluminium plate (6 mm) was carried out while the microstructure, strength, and fracture modes of the ensuing welds were compared with the conventional (single-sided) friction stir welded counterparts. The stepwise double-sided FSW-welded joint demonstrated better tensile strength relative to the single-sided FSW-welded counterparts owing to its material flow consolidation (two-side deformation) and elimination of penetration-induced fractional unbonded region/root defect. The welding processes do not have a noteworthy influence on the fracture location of the welds as failure ensued via the stir zones of the respective welds. Transient breaking/brittle appearance, and ductile fracture modes were noticed in the single-sided and stepwise double-sided FSW-welded samples respectively. The stepwise double-sided FSW process is recommended as a better choice for thick workpieces relative to conventional FSW to improve the weld’s loadbearing resistance.

Keywords

• Friction stir welding
• Aluminium alloy
• Microstructure
• Mechanical Properties
• Fracture

References

1. Wang, Z. L., Zhang, Z., Xue, P., Ni, D. R., Ma, Z. Y., Hao, Y. F., Zhao, Y. H., & Wang, G. Q. (2022). Defect formation, microstructure evolution, and mechanical properties of bobbin tool friction–stir welded 2219-T8 alloy. Materials Science and Engineering: A, 832, 142414.
2. Bayazid, S. M., Farhangi, H., & Ghahramani, A. (2015). Effect of pin profile on defects of friction stir welded 7075 aluminium alloy. Procedia Materials Science, 11, 12–16.
3. Shirazi, H., Kheirandish, S., & Safarkhanian, M. A. (2015). Effect of process parameters on the macrostructure and defect formation in friction stir lap welding of AA5456 aluminium alloy. Measurement, 76, 62–69.
4. Ojo, O. O., Taban, E., Kaluc, E., & Sik, A. (2019). Cyclic lateral behavior of friction stir spot welds of AA2219 aluminium alloy: Impact of inherent flow defects. Kovove Materialy, 57, 329–342.
5. Ebrahimzadeh, V., Paidar, M., Safarkhanian, M. A., & Oladimeji, O. O. (2018). Orbital friction stir lap welding of AA5456-H321/AA5456-O aluminium alloys under varied parameters. International Journal of Advanced Manufacturing Technology, 96, 1237–1254.
6. Shankar, S., Saw, K., Chattopadhyaya, S., & Hloch, S. (2018). Investigation on different type of defects, temperature variation and mechanical properties of friction stir welded lap joint of aluminium alloy 6101-T6. Materials Today: Proceedings, 5, 24378–24386.
7. Yi, T., Liu, S., Fang, C., & Jiang, G. (2020). Eliminating hole defects and improving microstructure and mechanical properties of friction stir welded joint of 2519 aluminium alloy via TIG arc. Journal of Materials Processing Technology, 310, 117773.
8. Wang, X., & Lados, D. A. (2022). Friction stir welding of similar aluminium alloys thick plates: Understanding the material flow, microstructure evolution, defect formation, and mechanical properties. Materialia, 24, 101508.

9. Mehrez, S., Paidar, M., Cooke, K., Vihnesh, R. V., & Ojo, O. O. (2021). Comparative study on weld characteristics of AA5083-H112 to AA6061-T6 sheets produced by MFSC and FSSW processes. Vacuum, 190, 110298.
10. Entringer, J., Meisnar, M., Reimann, M., Blawert, C., Zheludkevich, M., & dos Santos, J. F. (2019). The effect of grain boundary precipitates on stress corrosion cracking in a bobbin tool friction stir welded Al-Cu-Li alloy. Materials Letters: X, 2, 100014.
11. Xu, W., Wang, H., Luo, Y., Li, W., & Fu, M. W. (2018). Mechanical behavior of 7085-T7452 aluminium alloy thick plate joint produced by double-sided friction stir welding: Effect of welding parameters and strain rates. Journal of Manufacturing Processes, 35, 261–270.
12. Rahmatian, B., Dehghani, K., & Mirsalehi, S. E. (2020). Effect of adding SiC nanoparticles to nugget zone of thick AA5083 aluminium alloy joined by using double-sided friction stir welding. Journal of Manufacturing Processes, 52, 152–164.
13. Chen, J., Fujii, H., Sun, Y., Morisada, Y., & Ueji, R. (2013). Fine grained Mg–3Al–1Zn alloy with randomized texture in the double-sided friction stir welded joints. Materials Science and Engineering: A, 580, 83–91.
14. Khalid, E., Shunmugasamy, V. C., & Mansoor, B. (2022). Microstructure and tensile behavior of a bobbin friction stir welded magnesium alloy. Materials Science and Engineering: A, 840, 142861.
15. Shao, M., Wang, C., Zhang, H., Zhang, J., Liu, D., Wang, F., Ji, Y., & Chen, G. (2022). Microstructure and corrosion behavior of bobbin tool friction stir welded 2219 aluminium alloy. Materials Characterization, 192, 112178.
16. Fuse, K., & Badheka, V. (2021). Effect of shoulder diameter on bobbin tool friction stir welding of AA 6061-T6 alloy. Materials Today: Proceedings, 42, 810–815.
17. Wu, D., Li, W., Liu, X., Gao, Y., Wen, Q., & Vairis, A. (2021). Effect of material configuration and welding parameter on weld formability and mechanical properties of bobbin tool friction stir welded Al-Cu and Al-Mg aluminium alloys. Materials Characterization, 182, 111518.
18. Chu, Q., Li, W. Y., Wu, D., Liu, X. C., Hao, S. J., Zou, Y. F., Yang, X. W., & Vairis, A. (2021). In-depth understanding of material flow behavior and refinement mechanism during bobbin tool friction stir welding. International Journal of Machine Tools and Manufacture, 171, 103816.
19. Li, G. H., Zhou, L., Luo, S. F., Dong, F. B., & Guo, N. (2020). Quality improvement of bobbin tool friction stir welds in Mg-Zn-Zr alloy by adjusting tool geometry. Journal of Materials Processing Technology, 282, 116685.
20. Li, G. H., Zhou, L., Zhang, H. F., Guo, G. Z., Luo, S. F., & Guo, N. (2021). Evolution of grain structure, texture and mechanical properties of a Mg–Zn–Zr alloy in bobbin friction stir welding. Materials Science and Engineering: A, 799, 140267.
21. Sahu, P. K., Vasudevan, N. P., Das, B., & Pal, S. (2016). Assessment of self-reacting bobbin tool friction stir welding for joining AZ31 magnesium alloy at inert gas environment. Journal of Magnesium and Alloys, 7, 661–671.
22. Li, G., Zhou, L., Zhang, J., Luo, S., & Guo, N. (2014). Macrostructure, microstructure and mechanical properties of bobbin tool friction stir welded ZK60 Mg alloy joints. Materials Research and Technology, 9, 9348–9361.
23. Li, G., Zhou, L., Luo, S., Dong, F., & Guo, N. (2020). Microstructure and mechanical properties of bobbin tool friction stir welded ZK60 magnesium alloy. Materials Science and Engineering: A, 776, 138953.
24. Li, G., Zhou, L., Zhang, H., Luo, S., & Guo, N. (2021). Effects of traverse speed on weld formation, microstructure and mechanical properties of ZK60 Mg alloy joint by bobbin tool friction stir welding. Chinese Journal of Aeronautics, 34, 238–250.
25. Li, W. Y., Fu, T., Hütsch, L., Hilgert, J., Wang, F. F., dos Santos, J. F., & Huber, N. (2014). Effects of tool rotational and welding speed on microstructure and mechanical properties of bobbin-tool friction-stir welded Mg AZ31. Materials & Design, 64, 714–720.
26. Yang, C., Zhang, J. F., Ma, G. N., Wu, L. H., Zhang, X. M., He, G. Z., Xue, P., Ni, D. R., Xiao, B. L., Wang, K. S., & Ma, Z. Y. (2020). Microstructure and mechanical properties of double-side friction stir welded 6082Al ultra-thick plates. Journal of Materials Science & Technology, 41, 105–116.
27. Entringer, J., Reimann, M., Norman, A., & dos Santos, J. F. (2019). Influence of Cu/Li ratio on the microstructure evolution of bobbin-tool friction stir welded Al–Cu–Li alloys. Journal of Materials Research and Technology, 8, 2031–2040.
28. Chu, Q., Li, W. Y., Hou, H. L., Yang, X. W., Vairis, A., Wang, C., & Wang, W. B. (2019). On the double-side probeless friction stir spot welding of AA2198 Al-Li alloy. Journal of Materials Science & Technology, 35, 784–789.
29. Nosrati, H. G., Yazdani, N. M., & Khoran, M. (2022). Double-sided friction stir welding of AA 2024-T6 joints: Mathematical modeling and optimization. CIRP Journal of Manufacturing Science and Technology, 36, 1–11.
30. Azeez, S. T., & Akinlabi, E. T. (2018). Effect of processing parameters on microhardness and microstructure of a double-sided dissimilar friction stir welded AA6082-T6 and AA7075-T6 aluminium alloy. Materials Today: Proceedings, 5, 18315–18324.
31. Ke, W. C., Oliveira, J. P., Ao, S. S., Teshome, F. B., Chen, L., Peng, B., & Zeng, Z. (2022). Thermal process and material flow during dissimilar double-sided friction stir spot welding of AZ31/ZK60 magnesium alloys. Journal of Materials Research and Technology, 17, 1942–1954.
32. Thakur, A., Sharma, V., & Bhadauria, S. S. (2021). Effect of tool tilt angle on weld joint strength and microstructural characterization of double-sided friction stir welding of AZ31B magnesium alloy. CIRP Journal of Manufacturing Science and Technology, 35, 132–145.
33. Darmadi, D. B., & Talice, M. (2011). Improving the strength of friction stir welded joint by double-side friction welding and varying pin geometry. Engineering Science and Technology, an International Journal, 24, 637–647.
34. Wang, F. F., Li, W. Y., Shen, J., Wen, Q., & dos Santos, J. F. (2018). Improving weld formability by a novel dual-rotation bobbin tool friction stir welding. Journal of Materials Science & Technology, 34, 135–139.
35. Chen, J., Ueji, R., & Fujii, H. (2015). Double-sided friction-stir welding of magnesium alloy with concave–convex tools for texture control. Materials & Design, 76, 181–189.
36. Wang, X., Morisada, Y., & Fujii, H. (2021). Interface strengthening in dissimilar double-sided friction stir spot welding of AZ31/ZK60 magnesium alloys by adjustable probes. Journal of Materials Science & Technology, 85, 158–168.
37. Wang, X., Morisada, Y., & Fujii, H. (2021). High-strength Fe/Al dissimilar joint with uniform nanometer-sized intermetallic compound layer and mechanical interlock formed by adjustable probes during double-sided friction stir spot welding. Materials Science and Engineering: A, 809, 141005.
38. Sun, Y., Fujii, H., & Morisada, Y. (2020). Double-sided friction stir welding of 40 mm thick low carbon steel plates using a pcBN rotating tool. Journal of Manufacturing Processes, 50, 319–328.
39. Yang, C., Ni, D. R., Xue, P., Xiao, B. L., Wang, W., Wang, K. S., & Ma, Z. Y. (2018). A comparative research on bobbin tool and conventional friction stir welding of Al-Mg-Si alloy plates. Materials Characterization, 145, 20–28.
40. Xu, W. F., & Liu, J. H. (2015). Microstructure evolution along thickness in double-side friction stir welded 7085 Al alloy. Transactions of Nonferrous Metals Society of China, 25, 3212–3222.
41. Wang, X., Morisada, Y., Ushioda, K., & Fujii, H. (2022). Double-sided friction stir spot welding of ultra-high strength C-Mn-Si martensitic steel by adjustable probes. Journal of Materials Processing Technology, 300, 117422.
42. Wang, X., Morisada, Y., & Fujii, H. (2021). Interface development and microstructure evolution during double-sided friction stir spot welding of magnesium alloy by adjustable probes and their effects on mechanical properties of the joint. Journal of Materials Processing Technology, 294, 117104.
43. Qiao, Q., Su, Y., Cao, H., Zhang, D., & Ouyang, Q. (2020). Effect of post-weld heat treatment on double-sided friction stir welded joint of 120 mm ultra-thick SiCp/Al composite plates. Materials Characterization, 169, 110668.
44. Ojo, O. O., Taban, E., & Kaluc, E. (2015). Friction stir spot welding of aluminium alloys: A recent review. Materialpruefung/Materials Testing, 57, 609–627.
45. Ojo, O. O., & Obasha, I. O. (2022). Modeling and optimization of friction stir stitching of AISI 201 stainless steel via Box-Behnken design methodology. Production Engineering Archives, 28, 132–140.
46. Ojo, O. O. (2019). Multi-objective optimization of friction stir spot welds of aluminium alloy using entropy measurement. International Journal of Engineering Research in Africa, 45, 28–41.
47. Oladimeji, O. O., Taban, E., & Kaluc, E. (2016). Understanding the role of welding parameters and tool profile on the morphology and properties of expelled flash of spot welds. Materials & Design, 108, 518–528.
48. Paidar, M., Kazemi, A., Mahrez, S., & Ojo, O. O. (2021). Investigation of modified friction stir clinching-brazing process of AA2024 Al/AZ31 Mg: Metallurgical and mechanical properties. Archives of Civil and Mechanical Engineering, 21, 115.
49. Paidar, M., Mehrez, S., Ojo, O. O., Mohanavel, V., Babaei, B., & Ravichandran, M. (2021). Modified friction stir clinching of AA6061-T6/AA5754-O joint: Effect of tool rotational speed and solution heat treatment on mechanical, microstructure, and fracture behaviors. Materials Characterization, 173, 110962.
50. Heydari, F., Amadeh, A. A., Ojo, O. O., Hasanniya, M. H., & Tamizifar, M. (2019). Microstructure and mechanical properties of autobody steel joined by friction stir spot welding. Sadhana - Academy Proceedings in Engineering Sciences, 44(3), 73.