PSI - Issue 52

ScienceDirect Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2022) 000 – 000 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2022) 000 – 000 Available online at www.sciencedirect.com Procedia Structural Integrity 52 (2024) 43–51

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2452-3216 © 2023 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of Professor Ferri Aliabadi 10.1016/j.prostr.2023.12.005 2452-3216 © 2023 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of Professor Ferri Aliabadi 1. Introduction Laser powder bed fusion (LPBF) is a manufacturing method that is part of the additive manufacturing (AM) technology branch. In contrast to conventional manufacturing procedures, AM techniques provide the possibility to design customizable components and reduce their weight while maintaining strength in critical sections of components. This process is called topological optimization of parts (Zhu et al. 2021). The opportunity to freely design components and preserve their mechanical properties facilitate the option for integration of sensorial devices within 2452-3216 © 2023 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of Professor Ferri Aliabadi 1. Introduction Laser powder bed fusion (LPBF) is a manufacturing method that is part of the additive manufacturing (AM) technology branch. In contrast to conventional manufacturing procedures, AM techniques provide the possibility to design customizable components and reduce their weight while maintaining strength in critical sections of components. This process is called topological optimization of parts (Zhu et al. 2021). The opportunity to freely design components and preserve their mechanical properties facilitate the option for integration of sensorial devices within © 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of Professor Ferri Aliabadi Abstract The present work focuses on the low-cycle fatigue (LCF) behavior of conventionally and additively manufactured (laser powder bed fusion (LPBF) technique, Ni-based VDM Alloy 699 XA. LCF tests were performed on miniature cylindrical specimens in a symmetrical push-pull cycle under strain control with a constant total strain amplitude at 23°C. Cyclic hardening/softening curves, cyclic stress-strain curves, and fatigue life curves were obtained. Despite the present manufacturing defects associated with the LPBF technology, the fatigue lifetime of the LPBF manufactured material is higher than that of conventionally prepared material. Fatigue crack initiation sites and fatigue crack propagation areas were investigated by means of scanning electron microscopy (SEM). A quantitative fractography of fracture surfaces was introduced to provide a detailed description of fatigue crack growth from the evaluation of striation spacing. The dependency of the stress intensity factor range on macroscopic crack growth rates was displayed in the form of the Paris Law. The differences in fatigue lifetimes and fatigue crack growth rates of additively manufactured and hot rolled solution annealed alloy 699 XA plate material were discussed and correlated with respect to the microstructural specifics of both material batches. Fracture, Damage and Structural Health Monitoring Fatigue lifetime assessment and crack propagation of Ni-based VDM Alloy 699 XA produced by additive manufacturing Tomáš Vražina a* , Ivo Šulák a , Benedikt Nowak b , Bhupesh Verma c , Ulrich Krupp d , Tomáš Kruml a a Institute of Physics of Materials, Czech Academy of Sciences , Žižkova 22, 616 00 Brno, Czech Republic b Research and Development Department, VDM Metals International GmbH, Kleffstraße 23, 58762 Altena, Germany c Digital Additive Production, RWTH Aachen University, Campus Boulevard 73, 52074 Aachen, Germany d Steel Institute IEHK, RWTH Aachen University, Intzestraße 1, 52072 Aachen, Germany Abstract The present work focuses on the low-cycle fatigue (LCF) behavior of conventionally and additively manufactured (laser powder bed fusion (LPBF) technique, Ni-based VDM Alloy 699 XA. LCF tests were performed on miniature cylindrical specimens in a symmetrical push-pull cycle under strain control with a constant total strain amplitude at 23°C. Cyclic hardening/softening curves, cyclic stress-strain curves, and fatigue life curves were obtained. Despite the present manufacturing defects associated with the LPBF technology, the fatigue lifetime of the LPBF manufactured material is higher than that of conventionally prepared material. Fatigue crack initiation sites and fatigue crack propagation areas were investigated by means of scanning electron microscopy (SEM). A quantitative fractography of fracture surfaces was introduced to provide a detailed description of fatigue crack growth from the evaluation of striation spacing. The dependency of the stress intensity factor range on macroscopic crack growth rates was displayed in the form of the Paris Law. The differences in fatigue lifetimes and fatigue crack growth rates of additively manufactured and hot rolled solution annealed alloy 699 XA plate material were discussed and correlated with respect to the microstructural specifics of both material batches. Keywords: Additive manufacturing, VDM 699 XA, Paris law, fatigue life performance, fatigue crack propagation Fracture, Damage and Structural Health Monitoring Fatigue lifetime assessment and crack propagation of Ni-based VDM Alloy 699 XA produced by additive manufacturing Tomáš Vražina a* , Ivo Šulák a , Benedikt Nowak b , Bhupesh Verma c , Ulrich Krupp d , Tomáš Kruml a a Institute of Physics of Materials, Czech Academy of Sciences , Žižkova 22, 616 00 Brno, Czech Republic b Research and Development Department, VDM Metals International GmbH, Kleffstraße 23, 58762 Altena, Germany c Digital Additive Production, RWTH Aachen University, Campus Boulevard 73, 52074 Aachen, Germany d Steel Institute IEHK, RWTH Aachen University, Intzestraße 1, 52072 Aachen, Germany Keywords: Additive manufacturing, VDM 699 XA, Paris law, fatigue life performance, fatigue crack propagation