PSI - Issue 76

Vladimír Mára et al. / Procedia Structural Integrity 76 (2026) 123–130

130

growth rate. The trend is linear for most specimens, except for T240, which is slightly outside the 95% confidence band. The highest value was calculated for T6 specimens with large amounts of brittle Fe intermetallics, and the lowest values have noHT and T200 specimens, where no significant structural changes have been documented.

4. Conclusion

This study examined how different heat treatments affect the microstructure and HCF performance of L-PBF AlSi10Mg alloy, focusing on defect influence and crack propagation mechanisms. The main conclusions are: • Different heat treatments impact the as-built cellular structure and fatigue behavior of LPBF AlSi10Mg differently. Conventional annealing gradually decomposes the β -Si eutectic phase as the temperature increases. In contrast, T6 treatments dissolve β -Si and reprecipitate Si and intermetallic particles. The cellular structure affects the ratio of fatigue fracture regions. • Defect size significantly impacts the scatter of S-N curves of annealed specimens, negating the effect of heat treatment. T6 treatment enhances fatigue life despite the higher porosity. The length of the initial crack growth gradually increases with the degradation of the β -Si phase, regardless of the size of the killer defect. • The fatigue crack growth rate increases with the decomposition of the β -Si network and is tied to the reduction of GND density. The as-built MP structure is more beneficial in terms of fatigue crack growth rate. The maximum SIF at the crack tip decreases with increasing annealing temperature, but it increases with the gradual degradation of the β -Si eutectic network after T6 treatment. The results emphasize the complex interplay between microstructure, defect characteristics, and heat treatment in determining fatigue life. Properly tailored post-processing strategies can mitigate the detrimental effects of defects and enhance the durability of AlSi10Mg components, particularly for fatigue-critical applications. Beausir B, Fundenberger J-J. Analysis Tools for Electron and X-ray diffraction, ATEX - software 2017. Bisht MS, Gaur V, Singh IV. On mechanical properties of SLM Al–Si alloy: Role of heat treatment-induced evolution of silicon morphology. Materials Science and Engineering: A 2022;858:144157. https://doi.org/10.1016/j.msea.2022.144157. Kohout J, V ě chet S. A new function for fatigue curves characterization and its multiple merits. International Journal of Fatigue 2001;23:175–83. https://doi.org/10.1016/S0142-1123(00)00082-7. Lehner P, Blinn B, Zhu T, Al-Zuhairi A, Smaga M, Teutsch R, et al. Influence of the as-built surface and a T6 heat treatment on the fatigue behavior of additively manufactured AlSi10Mg. International Journal of Fatigue 2024;187:108479. https://doi.org/10.1016/j.ijfatigue.2024.108479. Mára V, Kr č il J, Pilsová L. Problematic of heat treatment and its influence on mechanical properties of selectively laser melted AlSi10Mg alloy. Int J Adv Manuf Technol 2022;119:5743–61. https://doi.org/10.1007/s00170-021-08521-1. Matuš ů M, Džuberová L, Papuga J, Rosenthal J, Šimota J, Beránek L. Fatigue analysis and heat treatment comparison of additively manufactured specimens from AlSi10Mg alloy. International Journal of Fatigue 2024a;185:108357. https://doi.org/10.1016/j.ijfatigue.2024.108357. Matuš ů M, Rosenthal J, Papuga J, Šimota J, Džuberová L, Mára V, et al. Fatigue analysis of additively manufactured specimens from AlSi10Mg with different levels of powder recycling. Procedia Structural Integrity 2024b;54:135–42. https://doi.org/10.1016/j.prostr.2024.01.065. Miyajima Y, Nakamura Y, Konishi Y, Ishikawa K, Wang W, Takata N. Effect of low-temperature annealing on electrical resistivity and mechanical properties of laser-powder bed fused AlSi10Mg alloy. Materials Science and Engineering: A 2023;871:144876. https://doi.org/10.1016/j.msea.2023.144876. Nadot Y. Fatigue from Defect: Influence of Size, Type, Position, Morphology and Loading. International Journal of Fatigue 2022;154:106531. https://doi.org/10.1016/j.ijfatigue.2021.106531. Roveda I, Serrano-Munoz I, Haubrich J, Requena G, Madia M. Investigation on the fatigue strength of AlSi10Mg fabricated by PBF-LB/M and subjected to low temperature heat treatments. Materials & Design 2024;244:113170. https://doi.org/10.1016/j.matdes.2024.113170. Wu Z, Wu S, Bao J, Qian W, Karabal S, Sun W, et al. The effect of defect population on the anisotropic fatigue resistance of AlSi10Mg alloy fabricated by laser powder bed fusion. International Journal of Fatigue 2021;151:106317. https://doi.org/10.1016/j.ijfatigue.2021.106317. Xu ZW, Wang Q, Wang XS, Tan CH, Guo MH, Gao PB. High cycle fatigue performance of AlSi10mg alloy produced by selective laser melting. Mechanics of Materials 2020;148:103499. https://doi.org/10.1016/j.mechmat.2020.103499. Yaru L, Tiejun M, Tounan J, Bo Z, Le Y, Wenhang Y, et al. Aging temperature effects on microstructure and mechanical properties for additively manufactured AlSi10Mg. Materials Science and Technology 2023;39:1223–36. https://doi.org/10.1080/02670836.2022.2164128. Zhu X, Ma Y, Wu H, Li M, Lu X. In-situ tensile testing of fracture and strain in a selective laser melted AlSi10Mg alloy. Heliyon 2024;10:e34137. https://doi.org/10.1016/j.heliyon.2024.e34137. Acknowledgements This work was supported by the Czech Science Foundation Grant No. 23-05338S. References