Sains Malaysiana 55(1)(2026): 117-127

http://doi.org/10.17576/jsm-2026-5501-09

 

Balancing Strength and Ductility in AA7075 through Controlled Heat Treatment Parameters

(Mengimbangi Kekuatan dan Kemuluran dalam AA7075 melalui Parameter Rawatan Haba Terkawal)

 

LAY SHENG EWE^1,*, WENG KEAN YEW², EMADADDIN ABDO ALAZZANI¹, NOR ZAKIAH GORMENT³ & SENTHIL RATHI BALASUBRAMANI^4,5

 

¹College of Engineering, Institute of Sustainable Energy (ISE), Universiti Tenaga Nasional (UNITEN), Putrajaya Campus, Jalan IKRAM-UNITEN, 43000 Kajang, Selangor, Malaysia

²School of Engineering and Physical Science, Heriot-Watt University Malaysia, No 1, Jalan Venna P5/2, Precint 5, 62200 Putrajaya, Malaysia

³Department of Foundation & Diploma Studies, College of Computing & Informatics, Universiti Tenaga Nasional, Putrajaya Campus Uniten, Jalan Ikram-Uniten, 43000 Kajang, Selangor, Malaysia

⁴Department of Chemical Engineering, Sri Sivasubramaniya Nadar College of Engineering, Chennai-603 110, Tamil Nadu, India

⁵Centre of Excellence in Water Research (CEWAR), Sri Sivasubramaniya Nadar College of Engineering, Chennai-603 110, Tamil Nadu, India

 

Diserahkan: 25 September 2025/Diterima: 8 Januari 2026

 

Abstract

AA7075-T6 aluminium alloy, known for its high strength-to-weight ratio, is an ideal material for many industries, such as aerospace and structural engineering. However, its mechanical performance is highly sensitive to heat exposure, and inconsistent heat treatment practices across industries have resulted in varying performance outcomes. Despite the alloy’s importance, there is limited empirical data that systematically correlates specific heat treatment parameters with resulting mechanical properties. This study addresses this gap by investigating the effects of post-treatment heat exposure at 425 °C, 450 °C, and 475 °C for durations of 30 min and 60 min. Mechanical testing showed that tensile strength decreased from 600 MPa in the T6 condition to as low as 377 MPa after treatment at 425 °C for 60 min. Similarly, yield strength dropped from 540 MPa to 199 MPa under the same conditions. Hardness declined from approximately 91 HRB in the untreated state to 55 HRB after extended exposure. In contrast, elongation improved from 13.2% in the original condition to a maximum of 22.5%, indicating increased ductility. Young’s modulus remained stable at approximately 16.3-17.3 GPa across all heat-treatment conditions. These results show the importance of controlled heat treatment to maintain strength while improving ductility, providing useful understanding for optimizing AA7075 in demanding applications.

Keywords: Aluminium alloy AA7075; heat treatment; mechanical characteristics

 

Abstrak

Aloi aluminium AA7075-T6 yang dikenali dengan nisbah kekuatan-ke-berat yang tinggi, merupakan bahan yang ideal untuk banyak industri seperti aeroangkasa dan kejuruteraan struktur. Walau bagaimanapun, prestasi mekanikalnya sangat sensitif terhadap pendedahan haba dan amalan rawatan haba yang tidak tekal merentasi industri telah menghasilkan hasil prestasi yang berbeza-beza. Walaupun berkepentingan, terdapat data empirik yang terhad yang secara sistematik menghubungkan parameter rawatan haba tertentu dengan sifat mekanikal yang terhasil. Penyelidikan ini menangani jurang ini dengan mengkaji kesan pendedahan haba selepas rawatan pada 425 °C, 450 °C dan 475 °C untuk tempoh 30 minit dan 60 minit. Ujian mekanikal menunjukkan bahawa kekuatan tegangan menurun daripada 600 MPa dalam keadaan T6 kepada serendah 377 MPa selepas rawatan pada 425 °C selama 60 minit. Begitu juga, kekuatan hasil menurun daripada 540 MPa kepada 199 MPa di bawah keadaan yang sama. Kekerasan menurun daripada kira-kira 91 HRB dalam keadaan tidak dirawat kepada 55 HRB selepas pendedahan yang berpanjangan. Sebaliknya, pemanjangan bertambah baik daripada 13.2% dalam keadaan asal kepada maksimum 22.5%, menunjukkan peningkatan kemuluran. Modulus Young kekal stabil pada kira-kira 16.3-17.3 GPa merentasi semua keadaan rawatan haba. Keputusan ini menunjukkan kepentingan rawatan haba terkawal untuk mengekalkan kekuatan sambil meningkatkan kemuluran, memberikan pemahaman yang berguna untuk mengoptimumkan AA7075 dalam aplikasi yang mencabar.

Kata kunci: Aloi aluminium AA7075; ciri mekanikal; rawatan haba

 

RUJUKAN

Abd El-Hameed, A.M. & Abdel-Aziz, Y.A. 2021. Aluminium alloys in space applications. Journal of Advanced Research in Applied Sciences and Engineering Technology 22(1): 1-7. http://dx.doi.org/10.37934/araset.22.1.17

Andersen, S.J., Marioara, C.D., Friis, J., Wenner, S. & Holmestad, R. 2018. Precipitates in aluminium alloys. Advances in Physics: X 3(1): 1479984. https://doi.org/10.1080/23746149.2018.1479984

Bertolini, R., Simonetto, E., Pezzato, L., Fabrizi, A., Ghiotti, A. & Bruschi, S. 2021. Mechanical and corrosion resistance properties of AA7075-T6 sub-zero formed sheets. The International Journal of Advanced Manufacturing Technology 115: 2801-2824. https://doi.org/10.1007/s00170-021-07333-7

Chen, Y., Wei, W., Zhao, Y., Shi, W., Zhou, X., Rong, L., Wen, S., Wu, X., Gao, K., Huang, H. & Nie, Z. 2023. Effect of the solid solution and aging treatment on the mechanical properties and microstructure of a novel Al-Mg-Si alloy. Materials 16(21): 7036. https://doi.org/10.3390/ma16217036

Feizi, A.J. & Ashjari, M. 2018. 7xxx aluminum alloys: Strengthening mechanisms and heat treatment - A review. Material Science & Engineering International Journal 2(2): 52-56. https://doi.org/10.15406/mseij.2018.02.00034

Freitas, B.J.M. & Silva, D. 2018. Kinetic study of an AA7075 alloy under T6 heat treatment. Material-ES 2(3): 44-47.

Gandhi, C., Dixit, N., Mohanty, A. & Singh, B. 2019. Study on effect of heat treatment on mechanical properties of AA7075-MWCNT composite. Materials Today: Proceedings, 18(1): 37-46. https://doi.org/10.1016/j.matpr.2019.06.275

Georgantzia, E., Gkantou, M. & Kamaris, G.S. 2021. Aluminium alloys as structural material: A review of research. Engineering Structures 227: 111372. https://doi.org/10.1016/j.engstruct.2020.111372

Hsiao, T-J., Chiu, P-H., Tai, C-L., Tsao, T-C., Tseng, C-Y., Lin, Y-X., Chen, H-R., Chung, T-F., Chen, C-Y., Wang, S-H. & Yang, J-R. 2022. Effect of Cu additions on the evolution of eta-prime precipitates in aged AA7075 Al–Zn–Mg–Cu alloys. Metals 12(12): 2120. https://doi.org/10.3390/met12122120

Jiang, F., Huang, J., Jiang, Y. & Xu, C. 2021. Effects of quenching rate and over-aging on microstructures, mechanical properties and corrosion resistance of an Al–Zn–Mg (7046A) alloy. Journal of Alloys and Compounds 854: 157272. https://doi.org/10.1016/j.jallcom.2020.157272

Kumar, S., Srivastava, A.K. & Singh, R.K. 2020. Fabrication of AA7075 hybrid green metal matrix composites by friction stir processing technique. Annales de Chimie – Science des Matériaux44(4): 295-300. https://doi.org/10.18280/acsm.440409

Li, P., Zhang, M., Zhang, B. & Liu, K. 2023. Impact of aging treatment on microstructure and performance of Al-Zn-Mg-Cu alloy thin sheets. Metals 13(10): 1638. https://doi.org/10.3390/met13101638

Li, Q., Qin, J., Jiang, D., Yi, D. & Wang, B. 2022. Precipitate coarsening and mechanical properties in 6082 aluminium alloy during long-term thermal exposure. Journal of Alloys and Compounds 909: 164819. https://doi.org/10.1016/j.jallcom.2022.164819

Liu, S., Hou, H., Shao, W., Yang, J., Wang, Z., Yang, Q. & Llorca, J. 2024. Revisiting the precipitation mechanisms of Guinier–Preston zones, η′, and η precipitates in Al–Zn–Mg alloys. Acta Materialia268: 119789. https://doi.org/10.1016/j.actamat.2024.119789

Mehdi, H. & Mishra, R.S. 2020. Effect of friction stir processing on microstructure and mechanical properties of TIG welded joints of AA6061 and AA7075. Metallography, Microstructure, and Analysis 9: 403-418. https://doi.org/10.1007/s13632-020-00640-7

Rathinasuriyan, C., Puviyarasan, M., Sankar, R. & Selvakumar, V. 2024. The effect of friction stir welding parameters on mechanical properties of AA7075 alloy. Journal of Alloys and Metallurgical Systems 7: 100091. https://doi.org/10.1016/j.jalmes.2024.100091

Rometsch, P.A., Zhang, Y. & Knight, S. 2014. Heat treatment of 7xxx series aluminium alloys: Some recent developments. Transactions of Nonferrous Metals Society of China 24(7): 2003-2017. https://doi.org/10.1016/S1003-6326(14)63306-9

Silva, M.S., Barbosa, C., Acselrad, O. & Pereira, L.C. 2004. Effect of chemical composition variation on microstructure and mechanical properties of a 6060 aluminium alloy. Journal of Materials Engineering and Performance 13: 129-134. https://doi.org/10.1361/10599490418307

Sunar, T., Tuncay, T., Özyürek, D. & Gürü, M. 2020. Investigation of mechanical properties of AA7075 alloys aged by various heat treatments. Physics of Metals and Metallography 121: 1440-1446. https://doi.org/10.1134/S0031918X20140161

Wciślik, W. & Lipiec, S. 2022. Void-induced ductile fracture of metals: Experimental observations. Materials 15(18): 6473. https://doi.org/10.3390/ma15186473

 

*Pengarang untuk surat-menyurat; email: laysheng@uniten.edu.my