PSI - Issue 68

Available online at www.sciencedirect.com Structural Integrity Procedia 00 (2025) 000–000 Available online at www.sciencedirect.com ScienceDirect

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ScienceDirect

Procedia Structural Integrity 68 (2025) 974–980

European Conference on Fracture 2024 Elevated temperature fatigue behavior of notched specimens produced by L-PBF in Inconel 718 Giuseppe Macoretta a* , Bernardo Disma Monelli a , Filippo Berto b a Department of Civil and Industrial Engineering, University of Pisa, Largo L. Lazzarino 2, 56122, Pisa, Italy b Department of Chemical Engineering, Materials and Environment, Sapienza University of Rome, Via Eudossiana 18, 00184, Rome, RO, Italy Abstract The elevated temperature fatigue behavior and notch sensitivity of the Inconel 718 produced via Laser-Powder Bed Fusion (L PBF) were investigated. A smooth specimen and three geometries of 90° V-notched specimens were employed. The material was printed by employing a set of process parameters aimed at producing a full-dense material and was post-processed adopting a conventional solution and aging heat treatment. Three V-notch geometries were defined through FEM analyses to obtain theoretical stress concentration factors ranging from 1.5 to 3.5. Isothermal HCF tests were carried out at a temperature of 650°C and a load ratio R of 0.1. Fractographic investigations pointed out the features of the crack onset site for the different geometries. Metallographic analyses were employed to assess the effective notch geometry produced by the L-PBF process, as well as the material microstructure. © 2025 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 ECF24 organizers Keywords: HCF; L-PBF; elevated temperature; notch sensitivity; Inconel 718. 1. Introduction Inconel 718 is widely employed for high-temperature applications, such as mid-temperature turbine blades, turbine disks, and burner nozzles [1–3], where the complex geometries allowed by the Laser-Powder Bed Fusion (L-PBF) technology can be effectively exploited. Such components are typically subjected to elevated temperature fatigue cycles, which can include thermal-stress cycles or isothermal variable loadings. While the former case is typical of components subjected to severe loads for a few cycles, a wide range of components that can be successfully produced in Inconel 718 are subjected to high-frequency variable loads while exposed to elevated temperature, creating conditions typical of High Cycle Fatigue (HCF), [4]. © 2025 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 ECF24 organizers

2452-3216 © 2025 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 ECF24 organizers

2452-3216 © 2025 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 ECF24 organizers 10.1016/j.prostr.2025.06.159