PSI - Issue 80

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

www.elsevier.com/locate/procedia

Procedia Structural Integrity 80 (2026) 244–255

Fracture, Damage and Structural Health Monitoring Comparative Study of Fatigue Crack Growth in FCC and ODS BCC Materials with Emphasis on Intergranular Propagation Tomáš Vražina 1, 2* , Jaroslav Polák 1 , Ladislav Poczklán 1 , Ivo Šulák 1 , Jiří Svoboda 1

1 Institute of Physics of Materials, Czech Academy of Sciences , Žižkova 22, 61600 Brno, Czech Republic 2 Institute of Materials Science and Engineering, Brno University of Technology, Technická 2896/2, 61669 Brno, Czech Republic

Abstract

© 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 Ferri Aliabadi While transgranular cracking mechanisms have been extensively studied, intergranular propagation is less understood and is often attributed to environmental effects, carbide and oxide cracking. Recently, a novel mechanism for intergranular crack growth was identified in FCC alloys under cyclic loading, highlighting the specific conditions and features that drive this process. The performed research in this work extends the investigation to BCC alloys to evaluate whether the observed mechanisms are broadly applicable. The intergranular fatigue crack initiation and growth were investigated in polycrystalline Sanicro 25 (FCC alloy) and Fe-10Al-4Cr- 4Y₂O₃ (BCC ODS nanocomposite). Fractured surfaces were examined using scanning electron microscopy . The underlying dislocation structure of persistent slip bands (PSB) was scrutinized by transmission electron microscopy, and HR-EBSD correlations were performed. Persistent slip markings (PSM), which arise from cyclic plastic strain localization, were identified as critical in intergranular crack initiation by influencing grain boundary cohesion and displacing adjacent grains. A qualitative comparison clarifies distinctions between PSMs and striations, addressing common misinterpretations in fractography. The specific morphological and crystallographic features of PSMs and PSBs in both investigated materials are systematically analyzed. The observed differences are discussed in the context of their respective deformation mechanisms and microstructural constraints. These findings contribute to a more comprehensive understanding of intergranular fatigue crack initiation and propagation, particularly in relation to crystallographic slip activity and grain boundary interactions in materials with differing crystal structures. © 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 Keywords: Persistent slip bands, Oxide dispersion strengthening, High Resolution EBSD, Intergranular cracking

* Corresponding author: E-mail address: vrazina@ipm.cz

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

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 Ferri Aliabadi 10.1016/j.prostr.2026.02.024