|Monday, August 24|
Hydrogen in Magnesium Alloys
* Norbert Hort, Magnesium Innovation Centre, Germany
Yuanding Huang, Magnesium Innovation Centre, Germany
From the chemical composition and different process steps and parameters the microstructure and thus the property profile of a material results. As a rule, a material is selected or even developed specifically for an application. During production, processing and treatment, further environmental influences may occur, which are not initially planned. In the case of molten metals, for example, it is known that hydrogen can be absorbed by the melt. During casting and solidification, hydrogen then influences the formation of the microstructure and, in the worst case, can lead to porosity and thus to rejects. In addition, hydrogen can react with alloying elements and form hydrides, for example, which also have an effect on the property profile. In this paper we will show, using rare earth hydrides as an example, which hydrides are formed and, above all, how they can be identified.
Effect of laser treatment on Mg-Zn-Ca alloys
* Nuria Pulido González, Universidad Rey Juan Carlos, Spain
Belén Torres, Universidad Rey Juan Carlos, Spain
Joaquín Rams, Universidad Rey Juan Carlos, Spain
Mikhail Zheludkevich, Helmholtz-Zentrum Geesthacht, Germany
Mg-Zn-Ca alloys are suitable for biomedical applications since they present low density, mechanical properties close to those of the bone and they are biodegradable. However, their use is limited because of their rapid corrosion rate. Laser surface treatments constitute an alternative to improve the corrosion behaviour of Mg-based alloys. In this work, two different Mg-Zn-Ca alloys, Mg-1Zn-1Ca and Mg-3Zn-0.4Ca, have been laser-treated using a High Power Diode Laser (HPDL) controlling the laser power and the laser scanning speed. The influence of laser treatment on the microstructure and corrosion behaviour of these two Mg-Zn-Ca alloys have been established.
Acid pickling and electropolishing as pre-treatment for Fe-Mn-C alloys
* Letícia Andrade, Laval University - Laboratory for Biomaterials and Bioengineering (LBB), Canada
Carlo Paternoster, Laval University - Laboratory for Biomaterials and Bioengineering (LBB), Canada
Pascale Chevallier, Laval University - Laboratory for Biomaterials and Bioengineering (LBB), Canada
Sofia Gambaro, Laval University - Laboratory for Biomaterials and Bioengineering (LBB), Canada
Diego Mantovani, Laval University - Laboratory for Biomaterials and Bioengineering (LBB), Canada
For confidentiality reasons and unpublished results contained, the presentation is not available online anymore. However, should the abstract be of your interest, please feel free to contact firstname.lastname@example.org and we will put you in contact with the authors. Acid pickling and electropolishing are important pre-treatments for metallic alloys that needs an accurate surface stabilization, like FeMnC based steels, a degradable class of alloys suitable for biomedical applications. In this work the influence of surface properties of Fe-13Mn-1.2C after acid pickling and electropolishing treatments were discussed. A synergic effect between the temperature and time was observed where the roughness behavior is mainly controlled by time whereas the chemical composition by the temperature.
Influence of selective laser melting on a novel biodegradable FeMn-based alloy for implant applications
Martin Otto, Leibniz Institute for Solid State and Materials Research Dresden, Germany
Annett Gebert, Leibniz Institute for Solid State and Materials Research Dresden; Technische Universität Bergak, Germany
Fabian Kochta, Leibniz Institute for Solid State and Materials Research Dresden; Technische Universität Bergak, Germany
Stefan Pilz, Leibniz Institute for Solid State and Materials Research Dresden; Technische Universität Bergak, Germany
Uta Kühn, Leibniz Institute for Solid State and Materials Research Dresden; Technische Universität Bergak, Germany
Birgit Paul, Leibniz Institute for Solid State and Materials Research Dresden; Technische Universität Bergak, Germany
* Julia Kristin Hufenbach, Leibniz Institute for Solid State and Materials Research Dresden; Technische Universität Bergak, Germany
Additive manufacturing of biodegradable alloys for patient-specific implant applications is currently drawing increasing attention. Especially the combination of the selective laser melting (SLM) technique and biodegradable metallic materials presents a promising approach. Among these materials, biodegradable FeMn systems are promising for, e.g., vascular implant applications. This derives from their excellent processability, broad range of tuneable mechanical properties and high integrity during degradation. In this study, the influence of the SLM process on a novel Fe-30Mn-1C-0.02S TWIP (twinning induced plasticity) alloy regarding the microstructural, mechanical, corrosion and cytotoxic properties is investigated.
Method to evaluate toughness and crack propagation in metal mini-tubules
* Petra Maier, University of Applied Sciences Stralsund, Germany
Benjamin Clausius, University of Applied Sciences Stralsund, Germany
This kind of flaring test offers statements on the (fracture) toughness of mini- tubules. The amount of absorbed energy, the curve progression and micrographic investigations of the crack propagation allow statements on the interaction of microstructural features with the fracture behaviour. These data can be used to adjust the extrusion parameter.
The performance of Mg-based implants in MRI: A systematic review
* Jonathan Espiritu, Syntellix AG, Germany
Jan-Marten Seitz, Syntellix AG, Germany
Martin Meier, ZTL Imaging Center, Hannover Medical School
Magnesium-based implants are reemerging as a substantial amendment to standard orthopaedic im-plants. This systematic review aims to highlight the current performance of these implants during examinations with MRI. We also aim to summarise comparisons between Mg-based implants with current standards to reinforce the promotion of biodegradable implants in clinical practice. A comprehensive search of current literature on Mg-based implants and the utilisation of MRI in the studies was performed. Additionally, recorded artefact behaviour of Mg-based implants during MRI was investigated. A total of 10 studies were included in which MRI was employed to image Mg-based implants. Of those studies, four discuss artefact production caused by the implants. MRI successfully imaged regions of interest overall and produced fewer artefacts than other materials used in the studies. In particular, MRI was employed incontrast angiography, bone growth observation, bone infection healing, and blood perfusion. Positive findings presented in this review suggest and support the use of Mg-based implants due totheir successful visual compatibility with MRI techniques, regardless of their medical indication.
Interaction between degradable and permanent metallic implant materials: magnesium and titanium
* Vasyl Haramus, Helmholtz Zentrum Geesthacht: Centre for Materials and Coastal Research, Germany
Wolfgang Limberg, Helmholtz Zentrum Geesthacht: Centre for Materials and Coastal Research, Germany
Sviatlana Lamaka, Helmholtz Zentrum Geesthacht: Centre for Materials and Coastal Research, Germany
Di Mei, Helmholtz Zentrum Geesthacht: Centre for Materials and Coastal Research, Germany
Thomas Ebel, Helmholtz Zentrum Geesthacht: Centre for Materials and Coastal Research, Germany
The increasing application of temporary implants based on degradable metals leads to the possible interaction with permanent implants that are already present in the body. Also, such material interaction and galvanic corrosion play a key role in the development of partly degradable implants, which should combine the best properties of temporary and permanent parts and in best case produce the synergetic effects to enhance mechanical and biomedical characteristics. Titanium (Ti) well-known for stable implant properties and magnesium (Mg), as most thoroughly studied metal for degradable medical applications, are the best candidates for such investigation. Here we pay attention on possible changes within titanium during degradation of magnesium.
Growth and characterization of Mg alloy WE43 single crystal as a biodegradable metallic material
* Guangqi Zhang, University of Cincinnati, United States
Sergey Yarmolenko, North Carolina A&T State University, United States
Vesselin Shanov, University of Cincinnati, United States
This study features the synthesis and characterization of Mg alloy WE43 single crystals as a candidate for biodegradable metallic material
Degradation behaviour of additively manufactured WE43 and influence of surface condition
* Felix Benn, Queen's University Belfast, United Kingdom
Kerstin van Gaalen, National University of Ireland Galway, Ireland
Francesco D'Elia, Meotec GmbH, Germany
Savko Malinov, Queen's University Belfast, United Kingdom
Fraser Buchanan, Queen's University Belfast, United Kingdom
Alexander Kopp, Meotec GmbH, Germany
For confidentiality reasons and unpublished results contained, the presentation is not available online anymore. However, should the abstract be of your interest, please feel free to contact email@example.com and we will put you in contact with the authors. Recent advances in additive manufacturing (AM) of Magnesium alloy WE43 demonstrated how biodegradable Magnesium ca be manufactured, applying freedom of design of AM for orthopaedic implants. Rapid solidification rates of AM result in changed microstructure compared to conventionally produced WE43 parts, thus influencing degradation behaviour. By investigating short- and long-term degradation behaviour of three surface conditions (as printed, etched, machined) of printed WE43, it was found that surface roughness plays a critical role for initial degradation rate. Long-term behaviour was observed unaffected, but chemical etching of samples induced local passivation effects, leading to formation of large pits.
Simultaneously improving mechanical properties and corrosion resistances of biomedical Mg-Zn-Ca alloy with MgO addition
* Minfang Chen, School of Materials Science and Engineering, Tianjin University of Technology, China
Chaokun Tang, School of Materials Science and Engineering, Tianjin University of Technology, China
Zihan Zhao, School of Materials Science and Engineering, Tianjin University of Technology, China
Shaoyuan Lyu, School of Materials Science and Engineering, Tianjin University of Technology, China
Mg-Zn-Ca alloy aroused wide attention in the biological internal fixation because of its good biodegradability, biosafety and biocompatibility. But its poor mechanical properties and rapid corrosion rate need to be improved. In our study, biocompatible MgO nanoparticles (MgO NPs) were employed as reinforcement particles to the matrix, an extruded MgO/Mg-3Zn-0.2Ca composite material with high strength and high corrosion resistance were prepared and the mechanism of performance improving were illustrated.
Microstructure, mechanical properties and corrosion behavior of a Fe-Mn alloy with Si addition
* Jacopo Fiocchi, CNR ICMATE, Italy
Jannis Nicolas Lemke, SAES Getters, Italy
Stefano Zilio, SAES Getters, Italy
Carlo Alberto Biffi, CNR ICMATE, Italy
Ausonio Tuissi, CNR ICMATE, Italy
Alberto Coda, SAES Getters, Italy
The Fe-Mn system is highly auspicious for the development of biodegradable metals for orthopaedic and vascular applications.In this respect, the addition of Si could constitute an effective strategy to improve the mechanical properties and maintain a similar corrosion susceptibility without degenerating the biocompatibility. In this work, results on microstructure, mechanical properties and corrosion behaviour of a Fe-30Mn-5Si alloy are presented, discussed and assessed in comparison to Fe-Mn formulations