PSI - Issue 74

Kristýna Vašáková et al. / Procedia Structural Integrity 74 (2025) 99–105 Kristýna Vašáková et al. / Structural Integrity Procedia 00 (2025) 000–000

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• The microstructure of the LPBF AlSi9Cu3 alloy remains stable up to 250 °C. At 300 °C , the fine cellular structure and the surrounding network begin to rupture, resulting in a significant decrease in hardness. • The highest mechanical strength was achieved after direct aging T5 treatment ( 160 °C / 10 h), reaching a yield strength of 347 MPa and an ultimate tensile strength of 520 MPa, with only a slight reduction in elongation, making this condition highly effective. • Despite utilizing the precipitation potential of the alloy, the T6 treatment did not surpass the T5 condition in terms of tensile strength. This indicates that the original cellular microstructure plays a dominant role in the mechanical performance and cannot be fully compensated by conventional T6 heat treatment. Acknowledgements This research was supported by Brno University of Technology Specific research project [No. FSI-S-23-8305]. References Aboulkhair, N. T., Maskery, I., Tuck, C., Ashcroft, I., & Everitt, N. M. (2016). The microstructure and mechanical properties of selectively laser melted AlSi10Mg: The effect of a conventional T6-like heat treatment. Materials Science and Engineering: A , 667 , 139–146. https://doi.org/10.1016/J.MSEA.2016.04.092 Aboulkhair, N. T., Simonelli, M., Parry, L., Ashcroft, I., Tuck, C., & Hague, R. (2019). 3D printing of Aluminium alloys: Additive Manufacturing of Aluminium alloys using selective laser melting. Progress in Materials Science , 106 , 100578. https://doi.org/10.1016/J.PMATSCI.2019.100578 DIN EN 1706:2020. Aluminium and aluminium alloys – Castings – Chemical composition and mechanical properties . (2010). Fiocchi, J., Biffi, C. A., & Tuissi, A. (2020). Selective laser melting of high-strength primary AlSi9Cu3 alloy: Processability, microstructure, and mechanical properties. Materials & Design , 191 , 108581. https://doi.org/10.1016/J.MATDES.2020.108581 Fiocchi, J., Tuissi, A., & Biffi, C. A. (2021). Heat treatment of aluminium alloys produced by laser powder bed fusion: A review. Materials & Design , 204 , 109651. https://doi.org/10.1016/J.MATDES.2021.109651 Fiocchi, J., Colombo, C., Vergani, L. M., Fabrizi, A., Timelli, G., Tuissi, A., & Biffi, C. A. (2021). Heat Treatments for Stress Relieving AlSi9Cu3 Alloy Produced by Laser Powder Bed Fusion. Metals, 14(15), 4184 . https://doi.org/10.3390/ma14154184 Fousová, M., Dvorský, D., Michalcová , A., & Vojtěch, D. (2018). Changes in the microstructure and mechanical properties of additively manufactured AlSi10Mg alloy after exposure to elevated temperatures. Materials Characterization , 137 , 119–126. https://doi.org/10.1016/J.MATCHAR.2018.01.028 Kimura, T., & Nakamoto, T. (2016). Microstructures and mechanical properties of A356 (AlSi7Mg0.3) aluminum alloy fabricated by selective laser melting. Materials & Design , 89 , 1294–1301. https://doi.org/10.1016/J.MATDES.2015.10.065 Li, R. X., Li, R. D., Zhao, Y. H., He, L. Z., Li, C. X., Guan, H. R., & Hu, Z. Q. (2004). Age-hardening behavior of cast Al–Si base alloy. Materials Letters , 58 (15), 2096–2101. https://doi.org/10.1016/J.MATLET.2003.12.027 Lombardi, A., Sediako, D., Ravindran, C., & Barati, M. (2019). Analysis of precipitation, dissolution and incipient melting of Al2Cu in B206 Al alloy using in-situ neutron diffraction. Journal of Alloys and Compounds , 784 , 1017–1025. https://doi.org/10.1016/J.JALLCOM.2019.01.104 Rao, J. H., Zhang, Y., Zhang, K., Huang, A., Davies, C. H. J., & Wu, X. (2019). Multiple precipitation pathways in an Al-7Si-0.6Mg alloy fabricated by selective laser melting. Scripta Materialia , 160 , 66–69. https://doi.org/10.1016/J.SCRIPTAMAT.2018.09.045 Roudnická, M., Molnárová, O., Dvor ský, D., Křivský, L., & Vojtěch, D. (2020). Specific Response of Additively Manufactured AlSi9Cu3Fe Alloy to Precipitation Strengthening. Metals and Materials International , 26 (8), 1168–1181. https://doi.org/10.1007/s12540-019-00504-y Zamani, M., Seifeddine, S., & Jarfors, A. (2015). High Temperature Tensile Deformation Behavior and Failure Mechanisms of an Al-Si-Cu-Mg Cast Alloy – The Microstructural Scale Effect. Materials & Design , 86 . https://doi.org/10.1016/j.matdes.2015.07.084