1. In vitro corrosion-fatigue behaviour of rare-earth containing magnesium WE43 in sterile complex cell culture mediumJulia Nachtsheim, Songyun Ma, Jaka Burja, Alexander Köppl, Jan-Marten Seitz, Bernd Markert, 2024, original scientific article Abstract: Rare-earth containing magnesium alloys are promising biomedical materials for a new generation of biodegradable orthopaedic implant systems due to their excellent biocompatibility, mechanical and biodegradation properties. However, chemo-mechanical interactions in aggressive physiological corrosion environments result in rapid degradation and early loss of mechanical integrity, limiting its broader application for orthopaedic implants. To date, only few studies have assessed the corrosion-fatigue behaviour of medical-grade magnesium alloys in an organic physiological corrosion environment, especially under sterile test conditions. In the present work, the corrosion-fatigue behaviour of fine-grained medical-grade magnesium alloy WE43MEO was systematically analysed under in vitro conditions using an organic physiological fluid DMEM. The experimental results showed that the fatigue strength of the alloy is nearly unaffected by a 1-day precorrosion, while a 7-day precorrosion resulted in a significant deterioration of mechanical integrity. In corrosion-fatigue experiments, the fatigue life was considerably reduced by interactions between corrosion and fatigue damages. The SEM analysis revealed that the mixed mode of intergranular and transgranular fracture in the crack propagation zone transits to intergranular cracking dominant mode under the corrosion-fatigue conditions due to hydrogen embrittlement.
Keywords: corrosion-fatigue behaviour, stress corrosion mechanisms, biodegradable magnesium alloys, WE43, DMEM
Published in DiRROS: 02.08.2024; Views: 131; Downloads: 90
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2. Harmonizing microstructures and enhancing mechanical resilience : novel powder metallurgy approach for Zn–Mg alloysAnna Boukalová, Jiří Kubásek, David Nečas, Peter Minárik, Črtomir Donik, Drahomír Dvorský, Dalibor Vojtěch, Alena Michalcová, Matjaž Godec, Irena Paulin, 2024, original scientific article Abstract: Zinc alloys are recognised for their excellent biocompatibility and favourable corrosion rates, making them suitable for bioabsorbable implants. However, their mechanical properties necessitate improvement to fulfil the rigorous requirements of biomedical applications. This research focuses on engineering pseudo-harmonic structures within zinc alloys through a comprehensive method combining mechanical alloying, spark plasma sintering, and hot extrusion techniques. This fabrication process results in a composite material characterised by a soft core surrounded by a continuous, three-dimensional, ultrafine-grained hard shell. The experiment involved blending pure zinc with Zn–1Mg alloy powder, leading to the formation of both ductile zinc and fine-grained Zn–1Mg regions. While the Mg2Zn11 intermetallic phase was found to enhance the alloy's mechanical strength, the presence of oxide shells adversely affected the material's properties. The elimination of these shells via hot extrusion markedly improved the alloy's tensile strength, reaching an average value of tensile strength of 333 ± 7 MPa. This study provides significant insights into the material engineering of zinc-based alloys for biodegradable implant applications, demonstrating a viable approach to optimising their mechanical performance.
Keywords: zinc, magnesium, biodegradable, powder metallurgy, harmonic structure
Published in DiRROS: 23.07.2024; Views: 114; Downloads: 110
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4. Tuning the long-term corrosion behaviour of biodegradable WE43 magnesium alloy by PEO coatingJulia Nachtsheim, Songyun Ma, Jaka Burja, Barbara Šetina, Bernd Markert, 2023, original scientific article Keywords: long-term degradation, in vitro corrosion mechanisms: biodegradable, magnesium, DMEM fluid, hydrogen evolution, PEO coating
Published in DiRROS: 20.05.2024; Views: 222; Downloads: 126
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5. Microstructure and properties of an AZ61 alloy after extrusion with a forward-backward oscillating die without preheating of the initial billetAnna Dobkowska, Aleksandra Zielińska, Irena Paulin, Črtomir Donik, Maciej Łojkowski, Milena Koralnik, Bogusława Adamczyk-Cieślak, Krystian Paradowski, Marek Tkocz, Dariusz Kuc, Jiří Kubásek, Matjaž Godec, Wojciech Święszkowski, 2023, original scientific article Keywords: magnesium alloys, severe plastic deformation, microstructure, mechanical properties, corrosion, extrusion, high deformation ratio
Published in DiRROS: 17.05.2024; Views: 251; Downloads: 168
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6. In vitro and in vivo degradation behavior of Mg-0.45Zn-0.45Ca (ZX00) screws for orthopedic applicationsDiana C. Martinez, Anna Dobkowska, Romy Marek, Hanna Ćwieka, Jakub Jaroszewicz, T. Plociński, Črtomir Donik, Heike Helmholz, Bérengère Luthringer-Feyerabend, Berit Zeller-Plumhoff, Regine Willumeit-Römer, Wojciech Święszkowski, 2023, original scientific article Keywords: magnesium alloys, biodegradable implants, microstructure, electron microscopy, corrosion layers
Published in DiRROS: 08.03.2024; Views: 244; Downloads: 219
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7. In vitro evaluation of stress corrosion cracking susceptibility of PEO-coated rare-earth magnesium alloy WE43Julia Nachtsheim, Songyun Ma, Jaka Burja, Bernd Markert, 2024, original scientific article Keywords: stress corrosion cracking, PEO coating, biodegradable magnesium alloys, SCC test setup, in vitro experiments
Published in DiRROS: 07.02.2024; Views: 343; Downloads: 184
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8. The evolution of microstructure and mechanical properties of Zn-0.8Mg-0.2Sr alloy prepared by casting and extrusionJiří Kubásek, Jan Pinc, Klára Hosová, Markéta Straková, Orsolya Molnárová, Jan Duchoň, David Nečas, Miroslav Čavojský, Matjaž Godec, Irena Paulin, 2022, original scientific article Keywords: zinc, magnesium, biodegradable, microstructure, mechanical properties, texture
Published in DiRROS: 06.05.2022; Views: 920; Downloads: 280
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