PSI - Issue 74

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 74 (2025) 85–90

Eleventh International Conference on Materials Structure and Micromechanics of Fracture Modelling mechanical properties of nitrided microporous titanium Karel Slámečka a,b,c,* , Petr Skalka a,b , Lenka Drotárová a , Pavel Gejdoš a , Ladislav Čelko a , Edgar Benjamin Montufar a , Jaroslav Pokluda a,b,d

a Central European Institute of Technology, Brno University of Technology, Purkyňova 123, 612 00, Brno, Czechia b Faculty of Mechanical Engineering, Brno University of Technology, Technická 2, 616 69 Brno, Czechia c Institute of Physics of Materials, Czech Academy of Sciences, Žižkova 22, 616 62 Brno, Czechia d Faculty of Special Technology, Alexander Dubcek University of Trenčín, Ku kyselke 469, 911 06, Trenčín, Slovakia

© 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 the responsibility of Libor Pantělejev Abstract D irect ink writing of titanium followed by sintering enables fabrication of architectured lattices with open-porous filaments, which are promising candidates for biomedical and engineering applications. Low-temperature gas nitriding at 500 °C and 600 °C for 10 h produces volumetric titanium nitride coatings that enhance flexural modulus without sacrificing flexural strength, whereas nitriding at 700 °C markedly reduces strength due to the extensive formation of brittle compound layers. To elucidate the mechanistic origins of this strength reduction, this work presents a finite-element model of a single nitrided titanium sintering neck, a fundamental load-bearing unit in these microporous materials. The model incorporates experimentally measured thicknesses of the diffusion zone (DZ) and titanium nitride compound layer, as well as graded material properties in the DZ derived from theoretical nitrogen concentration profiles. Simulations of cooling from the nitriding temperature followed by tensile loading yield residual stress distributions and effective composite responses, providing a quantitative foundation for future fracture-mechanics modelling of sintering neck failure. © 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 the responsibility of Libor Pant ě lejev Keywords: Direct ink writing ; microporous titanium; gas nitriding; finite-element model. 1. Introduction Additive manufacturing (AM) techniques for metals offer new opportunities to design complex lattice structures with tailored mechanical and transport properties. Among these, sinter-based approaches such as direct ink writing (DIW) enable the fabrication of metallic components that combine designed lattice-scale macroporosity with controlled material-level microporosity, introduced via the sintering of metal powders ( e.g. , Montufar et al. (2020),

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 the responsibility of Libor Pant ě lejev

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 the responsibility of Libor Pantělejev 10.1016/j.prostr.2025.10.038