PSI - Issue 42

Available online at www.sciencedirect.com Available online at www.sciencedirect.com ^ĐŝĞŶĐĞ ŝƌĞĐƚ Structural Integrity Procedia 00 (2019) 000 – 000

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Procedia Structural Integrity 42 (2022) 328–335

23 European Conference on Fracture - ECF23 Qualification of uniform fatigue damage tolerance law for additively manufactured and cast Al-Si alloys Jochen Tenkamp*, Sebastian Stammkötter, Frank Walther

Chair of Materials Test Engineering (WPT), TU Dortmund University, Baroper Str. 303, 44227 Dortmund, Germany

© 2022 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 the scientific committee of the 23 European Conference on Fracture – ECF23 Abstract The demand on lightweight structures and materials are steadily growing in automotive and aerospace industries. Hypo-eutectic Al-Si alloys are promising candidates due to its high specific material strength and corrosion resistance. Near net shape manufacturing by additive manufacturing (AM) or castings allow a high resource efficiency. The complex geometries lead to a wide range of structural features due to process-induced variations in local cooling rate. Therefore, the relationships between structural characteristics (e.g. dendrites, grain, eutectic, porosity, lack of fusion) and fatigue behavior have to be understood to enable a lightweight and reliable design of Al-Si alloys. In this study, the effect of process and process-induced structural characteristics on stress-strain behavior (quasi-static, cyclic) and high cycle fatigue behavior were characterized. The specimens were processed by laser-based powder bed fusion (PBF-LB) and sand casting (SC) with variation in porosity and dendrite arm spacing. Hereby, the age-hardenable Al-Si alloys AlSi10Mg (AM, SC) and AlSi7Mg (SC) were investigated. AM batches were tested in as-built condition. All casting batches got a HIP densification and T6 heat treatment. The fatigue results were analyzed based on nominal stresses according to Woehler (S-N curve) and local stress intensity based on linear-elastic fracture mechanics (stress intensity factor) as well as elastic-plastic fracture mechanics (J integral). J integral based Shiozawa diagrams allowed a sufficient and uniform fatigue damage tolerance (FDT) assessment for all AM and SC alloys. Hereby, the FDT of Al-Si alloys were dominated by defects (size, position) and cyclic stress-strain behavior (yield strength, cyclic hardening). © 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of 23 European Conference on Fracture - ECF23 Keywords: Al-Si alloys; stress-strain behavior; high cycle fatigue; damage tolerance, fracture mechanics haracteristics (e.g. dendrites, grain, eutectic, porosity, lack of fusion) and fatigue behavior have to be understood to characteristics on s

* Corresponding author. Tel.: +49 231 755-8425; fax: +49 231 755-8029. E-mail address: jochen.tenkamp@tu-dortmund.de

2452-3216 © 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of 23 European Conference on Fracture - ECF23 e - ECF23

2452-3216 © 2022 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 the scientific committee of the 23 European Conference on Fracture – ECF23 10.1016/j.prostr.2022.12.040