GTAW Butt Welded 6061-T6 Aluminum: Post-process Heat Treatment Effect on Mechanical and Microstructural Features
Keywords:
Aluminum alloys, Welding, Heat treatment, Mechanical properties, Microstructure.Abstract
Welding of aluminum remains an important area of research, driven by current challenges, such as the observed reduction in mechanical properties after the joining process, commonly referred to as softening. Particularly, there is limited information on the impact of heat treatments on the mechanical properties of joints in AA6061 alloy. This study addresses this gap by presenting mechanical properties of AA6061 joints under three distinct conditions: one in its welded state and two subjected to different subsequent heat treatments. Findings reveal that joining process parameters, defects, and applied heat treatment influence joint efficiency. Primarily, subsequent heat treatments substantially impact the microstructure and final mechanical properties of the weld. Solubilizing heat treatment effectively dissolves precipitates in the microstructure, while aging treatment successfully restores mechanical properties due to precipitation hardening. However, it is crucial to note that joint defects play a key role in determining final mechanical properties and crack location post-fracture. Additionally, the mechanical strength of the joint is studied in tensile tests at different temperatures, finding that this parameter reaches its maximum value at low temperatures and decreases with increasing temperature. In contrast, elongation is more significant at higher temperatures, but reduced at lower temperatures. This comprehensive analysis addresses the interaction between welding conditions, heat treatments, and microstructural changes, providing valuable information for improving the joining process and enhancing mechanical performance in AA6061-T6 aluminum joints.
References
1. Georgantzia, E., Gkantou, M. & Kamaris, G. S. “Aluminium alloys as structural material: A review of research”. Eng. Struct. 227, 111372 (2021). 10.1016/j.engstruct.2020.111372.
2. Materials and applications, Part 1. in Welding handbook (eds. Connor, L. P., O’Brien, R. L., Oates, W. R. & American Welding Society) vol. Volume 3 (American Welding Society, 1987).
3. AWS D1.2/D1.2M Structural Welding Code - Aluminum. 83–87 (2013).
4. Habibi, I., Triyono & Muhayat, N. A “Review on Aluminum Arc Welding and It’s Problems”. in Proceedings of the 6th International Conference and Exhibition on Sustainable Energy and Advanced Materials (eds. Sabino, U., Imaduddin, F. & Prabowo, A. R.) 819–826 (Springer Singapore, 2020). 10.1007/978-981-15-4481-1_78.
5. Ramaswamy, A., Malarvizhi, S. & Balasubramanian, V. “Post-weld heat treatment effects on the tensile properties of cold metal arc welded AA 6061-T6 aluminum joints”. Mater. Test. 62, 69–76 (2020). 10.3139/120.111454
6. Rathinasuriyan, C., Kumar, V. S. S. & V, S. “Mechanical and Metallurgical Properties of GTAW, GMAW and FSW Lap Joints on AA6061-T6 Alloy”. Adv. Mater. Process. Technol. 8, 3231–3247 (2022). 10.1080/2374068X.2021.1946322
7. Guzmán, I. et al. “Tensile and fracture behavior in 6061-T6 and 6061-T4 aluminum alloys welded by pulsed metal transfer GMAW”. Int. J. Adv. Manuf. Technol. 103, 2553–2562 (2019). 10.1007/s00170-019-03673-7
8. Rodríguez-Hernández, T. et al. “First assessment on the microstructure and mechanical properties of gtaw-gmaw hybrid welding of 6061-t6 AA”. J. Manuf. Process. 59, 658–667 (2020). 10.1016/j.jmapro.2020.09.069
9. Soundararajan, R., Ramkumar, K. R., Sivasankaran, S. & Kim, H. S. “Enhancement of tensile strength in AA 6061-T6 plates joined by gas tungsten arc welding using high entropy alloy filler sheet”. Mater. Sci. Eng. A 832, 142481 (2022). 10.1016/j.msea.2021.142481
10. Anderston, T. Welding aluminum: questions and answers: a practical guide for troubleshooting aluminum welding-related problems. (American Welding Society, 2010).
11. ASTM International. ASTM E8/E8M - 16a Standard Test Methods for Tension Testing of Metallic Materials. in ASTM Volume 03.01 Metals – Mechanical Testing; Elevated and Low-Temperature Tests; Metallography vol. 03.01 (ASTM International, 2016).
12. ASTM International. ASTM E3-11 (2017) Standard Guide for Preparation of Metallographic Specimens. in ASTM Volume 03.01 Metals – Mechanical Testing; Elevated and Low-Temperature Tests; Metallography vol. 03.01 (ASTM International, 2017).
13. Dowling, N. E. & App, B. “Statistical variation in materials properties”. in Mechanical Behavior of Materials 798–806 (Prentice-Hall).
14. Matweb. Material Property Data Aluminum 6061-T6. https://asm.matweb.com/search/specificmaterial.asp?bassnum=ma6061t6. Retrieved November 20th, 2023.
15. The American Society of Mechanical Engineers. BPVC Section II-Materials-Part D-Properties-(Customary). (ASME, 2023).
16. Askeland, D. R. The Science and Engineering of Materials. (Springer US: Imprint: Springer, 1996).
17. Pan, M. et al. “A Study on Welding Characteristics, Mechanical Properties, and Penetration Depth of T-Joint Thin-Walled Parts for Different TIG Welding Currents: FE Simulation and Experimental Analysis”. Metals 12, 1157 (2022). 10.3390/met12071157
18. Evdokimov, A., Obrosov, A., Ossenbrink, R., Weiß, S. & Michailov, V. “Mechanical properties of dissimilar steel-aluminum welds”. Mater. Sci. Eng. A 722, 242–254 (2018). 10.1016/j.msea.2018.03.019
19. Samiuddin, M. et al. “Investigation on the process parameters of TIG-welded aluminum alloy through mechanical and microstructural characterization”. Def. Technol. 17, 1234–1248 (2021). 10.1016/j.dt.2020.06.012
20. Gómora, C. M., Ambriz, R. R., Curiel, F. F. & Jaramillo, D. “Heat distribution in welds of a 6061-T6 aluminum alloy obtained by modified indirect electric arc”. J. Mater. Process. Technol. 243, 433–441 (2017). 10.1016/j.jmatprotec.2017.01.003
21. Park, K. et al. “Effects of Cryogenic Treatment on Residual Stress and Tensile Properties for 6061 Al Alloy”. Taehan-Kŭmsok-Hakhoe-Chi J. Korean Inst. Met. Mater. 49, 9–19 (2011).
22. Lakshminarayanan, A. K., Balasubramanian, V. & Elangovan, K. “Effect of welding processes on tensile properties of AA6061 aluminium alloy joints”. Int. J. Adv. Manuf. Technol. 40, 286–296 (2009). 10.1007/s00170-007-1325-0
23. Ribeiro, A. S. & De Jesus, A. M. P. “Fatigue Behaviour of Welded Joints Made of 6061-T651 Aluminium Alloy”. in Aluminium Alloys, Theory and Applications (ed. Kvackaj, T.) (InTech, 2011). doi:10.5772/14489.
24. Wang, B., Xue, S., Ma, C., Wang, J. & Lin, Z. “Effects of Porosity, Heat Input and Post-Weld Heat Treatment on the Microstructure and Mechanical Properties of TIG Welded Joints of AA6082-T6”. Metals 7, 463 (2017). 10.3390/met7110463
25. Peng, D., Shen, J., Tang, Q., Wu, C. & Zhou, Y. “Effects of aging treatment and heat input on the microstructures and mechanical properties of TIG-welded 6061-T6 alloy joints”. Int. J. Miner. Metall. Mater. 20, 259–265 (2013). 10.1007/s12613-013-0721-8
26. Wang, J., Chen, X., Yang, L. & Zhang, G. “Effect of preheat & post-weld heat treatment on the microstructure and mechanical properties of 6061-T6 aluminum alloy welded sheets”. Mater. Sci. Eng. A 841, 143081 (2022). 10.1016/j.msea.2022.143081
27. Cheng, J. et al. “Improving heat-affected zone softening of aluminum alloys by in-situ cooling and post-weld rolling”. J. Mater. Process. Technol. 306, 117639 (2022). 10.1016/j.jmatprotec.2022.117639.
28. Yi, J., Wang, G., Li, S., Liu, Z. & Gong, Y. “Effect of post-weld heat treatment on microstructure and mechanical properties of welded joints of 6061-T6 aluminum alloy”. Trans. Nonferrous Met. Soc. China 29, 2035–2046 (2019). 10.1016/S1003-6326(19)65110-1
29. Dewan, M. W., Wahab, M. A. & Okeil, A. M. “Influence of Weld Defects and Postweld Heat Treatment of Gas Tungsten Arc-Welded AA-6061-T651 Aluminum Alloy”. J. Manuf. Sci. Eng. 137, 051027 (2015). 10.1115/1.4030333
30. Verma, R. P. & Kumar Lila, M. “A short review on aluminium alloys and welding in structural applications”. Mater. Today Proc. 46, 10687–10691 (2021). 10.1016/j.matpr.2021.01.447
31. Liu, F. J., Fu, L. & Chen, H. Y. “Microstructure evolution and fracture behaviour of friction stir welded 6061-T6 thin plate joints under high rotational speed”. Sci. Technol. Weld. Join. 23, 333–343 (2018). 10.1080/13621718.2017.1389837
32. Zhang, L. et al. Microstructure, mechanical properties and fatigue crack growth behavior of friction stir welded joint of 6061-T6 aluminum alloy. Int. J. Fatigue 135, 105556 (2020). 10.1016/j.ijfatigue.2020.105556
