PSI - Issue 54

Daniel F.O. Braga et al. / Procedia Structural Integrity 54 (2024) 631–637 Daniel F.O. Braga et al. / Structural Integrity Procedia 00 (2023) 000–000

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5. Conclusions Metal additive manufacturing is an emerging field, and given the rapid advancements in technological development and the design and economics benefits of their use, significant interest exists in their adoption in ever more safety critical applications. Nevertheless, as discussed in this review the thermal history of these processes, the base materials and process conditions, lead to complex, non-isotropic micro- and meso structures which condition the structural integrity of the parts to be manufactured. These alter quasi-static strength and ductility, along with, fatigue strength and life, fracture toughness, fatigue crack growth, and corrosion resistance. Through process parameters tuning as well as post processing, the resulting micro and meso- structures can be modified, as to mitigate their anisotropic nature and this way approach the charachteristics of conventional manufactured components. Regarding hybrid metal AM processes, such as, the combination of SLM and LMD, it is shown to be a topic of industrial relevancy given the possibility of design optimization, combined with cost reductions and larger scale capabilities. The very different process thermal history and process characteristics results in sharp transitions in the micro- and meso- structures which highly impacts the structural integrity of the components produced even further, adding another layer of complexity. Given the reported effect of these anisotropic structures, the impact of this sharp transitions should be felt on almost all structural integrity relevant metrics. However, this is still a topic that has not been extensively addressed in the literature and is a research gap that should be filled to allow further adoption of these hybrid approaches to safety critical parts and systems. Acknowledgements The authors acknowledge the project POCI- 01-0247-FEDER-072260, financed by European Funds, through program COMPETE2020, under the Eureka smart label S0318-STREAM -Surface TREatment for Additive Manufacturing. References Becker, T.H., Kumar, P., Ramamurty, U., 2021. Fracture and fatigue in additively manufactured metals. Acta Materialia 219, 117240. URL: https://www.sciencedirect.com/science/article/pii/S1359645421006200 , doi: https://doi.org/10. 1016/j.actamat.2021.117240 . Dhansay, N.M., 2015. Fracture mechanics based fatigue and fracture toughness evaluation of SLM Ti-6Al-4V. Master’s thesis. University of Cape Town. Findlay, S., Harrison, N., 2002. Why aircraft fail. Materials Today 5, 18–25. URL: https://www.sciencedirect.com/science/ article/pii/S1369702102011380 , doi: https://doi.org/10.1016/S1369-7021(02)01138-0 . Frazier, W.E., 2010. Direct digital manufacturing of metallic components: vision and roadmap, in: 2010 International Solid Freeform Fabrication Symposium, University of Texas at Austin. Frazier, W.E., 2014. Metal additive manufacturing: a review. Journal of Materials Engineering and performance 23, 1917–1928. Gorelik, M., 2017. Additive manufacturing in the context of structural integrity. International Journal of Fatigue 94, 168– 177. URL: https://www.sciencedirect.com/science/article/pii/S0142112316301906 , doi: https://doi.org/10.1016/j. ijfatigue.2016.07.005 . fatigue and Fracture Behavior of Additive Manufactured Parts. Graf, B., Schuch, M., Kersting, R., Gumenyuk, A., Rethmeier, M., 2015. Additive process chain using selective laser melting and laser metal deposition, in: Lasers in Manufacturing Conference. Greitemeir, D., Schmidtke, K., Holzinger, V., Donne, C., 2013. Additive layer manufacturing of ti-6al-4v and scalmalloyrp © fatigue and fracture, in: 27th ICAF Symposium. Hemmasian Ettefagh, A., Zeng, C., Guo, S., Raush, J., 2019. Corrosion behavior of additively manufactured ti-6al-4v parts and the effect of post annealing. Additive Manufacturing 28, 252–258. URL: https://www.sciencedirect.com/science/ article/pii/S2214860418307796 , doi: https://doi.org/10.1016/j.addma.2019.05.011 . Ko, G., Kim, W., Kwon, K., Lee, T.K., 2021. The corrosion of stainless steel made by additive manufacturing: A review. Metals 11, 516. Kumar, P., Ramamurty, U., 2019. Microstructural optimization through heat treatment for enhancing the fracture toughness and fatigue crack growth resistance of selective laser melted ti6al4v alloy. Acta Materialia 169, 45–59. URL: https://www. sciencedirect.com/science/article/pii/S1359645419301363 , doi: https://doi.org/10.1016/j.actamat.2019.03.003 .