Investigating the Effect of T6 Heat Treatment on Mechanical Properties of 7075 Al Alloy
Subject Areas :
Mohsen Emami
1
(Department of Mechanical Engineering, Behbahan Khatam Alanbia University of Technology, Behbahan, Iran)
Vahid Hasan Nasab
2
(Department of Mechanical Engineering, Behbahan Khatam Alanbia University of Technology, Behbahan, Iran)
Keywords: T6 Heat Treatment, Age Hardening, Aluminum Alloy 7075, Taguchi, Mechanical Properties, Optimization,
Abstract :
Age hardening is one of the most important methods used to improve the mechanical properties of non-ferrous alloys such as nickel, titanium, magnesium, and aluminum alloys. However, finding the optimal age hardening parameters to achieve higher mechanical properties—such as hardness, yield stress, tensile strength, and fatigue life—is essential. In this study, the effect of T6 heat treatment parameters, including solution and aging conditions, on the mechanical properties of commercial alloy 7075 was investigated. The Taguchi method was employed to design the experiments and analyze the results. Solution temperature, solution time, aging temperature, and aging time were the T6 heat treatment factors considered in this design. Temperatures of 430, 470, and 510 °C and times of 15, 35, and 55 minutes were set as the solution treatment levels. Additionally, temperatures of 140, 170, and 200 °C and times of 2, 7, and 12 hours were determined as the aging treatment levels. Upon optimization, the material achieved a Vickers hardness of 137.28 HV, yield strength of 266.91 MPa, tensile strength of 377.64 MPa, elongation to break of 15.19%, and fatigue life of 1,193,304 cycles. According to the research findings, achieving optimal mechanical properties such as hardness, tensile strength, and fatigue strength requires specific and distinct heat treatment conditions.
[1] Handbook A. 1991. Heat Treating of Aluminum Alloys. ASM Handbook.
[2] Hadjadj, L., Amira, R., Hamana, D. and Mosbah, A. 2008. Characterization of precipitation and phase transformations in Al–Zn–Mg alloy by the differential dilatometry. Journal of Alloys and Compounds. 462(1-2): 279-283. doi:10.1016/j.jallcom.2007.08.016.
[3] Sha, G. and Cerezo, A. 2004. Early-stage precipitation in Al–Zn–Mg–Cu alloy (7050). Acta Materialia. 52(15): 4503-4516. doi:10.1016/j.actamat.2004.06.025.
[4] Andreatta, F., Terryn, H. and De Wit, J. 2003. Effect of solution heat treatment on galvanic coupling between intermetallics and matrix in AA7075-T6. Corrosion Science. 45(8): 1733-1746. doi:10.1016/S0010-938X(03)00004-0.
[5] Luiggi, N.J. and Valera, M.d.V. 2017. Kinetic study of an AA7075 alloy under RRA heat treatment. Journal of Thermal Analysis and Calorimetry. 130: 1885-1902. doi:10.1007/s10973-017-6683-8.
[6] Tiringer, U., Kovač, J., and Milošev, I. 2017. Effects of mechanical and chemical pre-treatments on the morphology and composition of surfaces of aluminium alloys 7075-T6 and 2024-T3. Corrosion Science. 119: 46-59. doi:10.1016/j.corsci.2017.02.018.
[7] Song, M. and Chen, K. 2008. Effects of the enhanced heat treatment on the mechanical properties and stress corrosion behavior of an Al–Zn–Mg alloy. Journal of Materials Science. 43: 5265-5273. doi:10.1007/s10853-008-2773-0.
[8] Chen, Q., Zhao, W., Jiang, J., Huang, M., Li, M., Wang, Y., Ding, C., and Zou, D. 2023. Effect of T6 heat treatment on microstructure and mechanical properties of large-weight aluminum alloy flywheel housing parts formed by local-loading squeeze casting. Journal of Materials Research and Technology. 24: 1612-25. doi:10.1016/j.jmrt.2023.03.084.
[9] Sowrabh, B.S., Gurumurthy, B.M., Shivaprakash, Y.M., and Sharma, S.S. 2023. Characterization studies on 7075 aluminium alloy under as-cast and in multiple step T6 conditions. Journal of The Institution of Engineers (India): Series C. 104(1): 69-92. doi:10.1007/s40032-022-00909-6.
[10]. Cetin, M.H., Ozcelik, B., Kuram, E. and Demirbas, E. 2011. Evaluation of vegetable based cutting fluids with extreme pressure and cutting parameters in turning of AISI 304L by Taguchi method. Journal of Cleaner Production. 19(17-18): 2049-2056. doi:10.1016/j.jclepro.2011.07.013.
[11] Baghel, M., Krishna, C., Namdev, A Kumar, A. and Yadav, Y. K. 2023. Optimization of heat treatment parameters using Taguchi method to improve compressive strength of MWCNTs/Al6082 composites. Materials Today: Proceedings. 82: 263-269. doi:10.1016/j.matpr.2023.01.221.
[12] ISO 1143:2010. 2021. Metallic materials-Rotating bar bending fatigue testing. SECfS.
[13] Sailaja, M., Rao, C. M., Bhuvaneswari, K., Lavanya, M.S., Shanmuka Priya, N. and Chandini, P. 2021. Application of Taguchi method and ANOVA for the optimization of AA6061-T6 responses. Journal of Mechanical and Mechanics Engineering. 7(2): 53-61.
[14] Freddi, A. and Salmon, M.2019. Design Principles and Methodologies. Springer. doi:10.1007/978-3-319-95342-7.
[15] Xu, D., Rometsch, P. and Birbilis, N. 2012. Improved solution treatment for an as-rolled Al–Zn–Mg–Cu alloy. Part I. Characterisation of constituent particles and overheating. Materials Science and Engineering: A. 534: 234-243. doi:10.1016/j.msea.2011.11.065.