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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Procedia Structural Integrity 68 (2025) 936–941

European Conference on Fracture 2024 Fracture-mechanical assessment of the effect of defects on the fatigue life of additively manufactured titanium aluminides Mirko Teschke a, *, Frank Walther a a TU Dortmund University, Chair of Materials Test Engineering (WPT), Baroper Straße 303, D-44227 Dortmund, Germany Abstract The additively manufactured titanium aluminide alloy TNM-B1 was microstructurally and mechanically characterized in the as built and the hot isostatically pressed (HIP) condition. Constant amplitude tests were performed at room temperature and 800 °C. Fractographic SEM images were used to identify the fracture-inducing defects. HIP processing significantly reduced the number and size of defects, resulting in improved fatigue strength. By applying the Murakami and Shiozawa approaches, fatigue life was correlated with the local stress intensity factor and could be described as a function of stress amplitude, as well as the size and location of the fracture-inducing defect. A method was developed to quantify the effect of manufacturing defects on fatigue life using local defect-based S-N curves. © 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: Titanium aluminides; additive manufacturing; high cycle fatigue, defect-based lifetime prediction; fracture mechanical approaches 1. Introduction Additive manufacturing (AM) enables the fabrication of complex components such as internal cooling channels, undercuts, bionic-inspired structures, and customized implants. In technical applications, the fatigue behavior of these additively manufactured materials and structures is determined not only by their microstructure but also by existing defects and surface roughness. It is therefore crucial to comprehensively understand and investigate the influence of microstructure and defects on mechanical performance. Manufacturing-related defects cannot be completely avoided © 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

* Corresponding author. Tel.: +49 231 755 8040; fax: +49 231 755 8029. E-mail address: mirko.teschke@tu-dortmund.de

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.2025.06.153