%0 journal article %@ 2213-9567 %A Chen, T., Fu, B., Shen, J., Suhuddin, U.F.H.R., Wiese, B., Huang, Y., Wang, M., dos Santos, J.F., Bergmann, J.P., Klusemann, B. %D 2023 %J Journal of Magnesium and Alloys %R doi:10.1016/j.jma.2023.10.007 %T Application of novel constrained friction processing method to produce fine grained biomedical Mg-Zn-Ca alloy %U https://doi.org/10.1016/j.jma.2023.10.007 %X In order to obtain Mg alloys with fine microstructures and high mechanical performances, a novel friction-based processing method, name as “constrained friction processing (CFP)”, was investigated. Via CFP, defect-free Mg-Zn-Ca rods with greatly refined grains and high mechanical properties were produced. Compared to the previous as-cast microstructure, the grain size was reduced from more than 1 mm to around 4 µm within 3 s by a single process cycle. The compressive yield strength was increased by 350% while the ultimate compressive strength by 53%. According to the established material flow behaviors by “tracer material”, the plastic material was transported by shear deformation. From the base material to the rod, the material experienced three stages, i.e. deformation by the tool, upward flow with additional tilt, followed by upward transportation. The microstructural evolution was revealed by “stop-action” technique. The microstructural development at regions adjacent to the rod is mainly controlled by twinning, dynamic recrystallization (DRX) as well as particle stimulated nucleation, while that within the rod is related to DRX combined with grain growth. %0 conference lecture %@ %A Dühring, N., Petersen, N., Helmholz, H., Wiese, B., Hort, N. %D 2023 %J 15th International Symposium on Biodegradable Metals %T Rotary barrel finishing for magnesium sample preparation %U %X %0 dataset %@ %A Berger, S., Wiese, B., Bohlen, J., Nienaber, M., Hoeche, D. %D 2023 %J zenodo %R doi:10.5281/zenodo.7695823 %T Dataset and scripts for publication Property design of extruded magnesium-gadolinium alloys through machine learning %U https://doi.org/10.5281/zenodo.7695823 %X Data and scripts accompanying publication "Property design of extruded magnesium-gadolinium alloys through machine learning" https://doi.org/10.1016/j.mtcomm.2023.106566 %0 journal article %@ 2352-4928 %A Wiese, B., Berger, S., Bohlen, J., Nienaber, M., Höche, D. %D 2023 %J Materials Today : Communications %P 106566 %R doi:10.1016/j.mtcomm.2023.106566 %T Property design of extruded magnesium-gadolinium alloys through machine learning %U https://doi.org/10.1016/j.mtcomm.2023.106566 %X Advanced machine learning (ML) techniques can be used to enable fast processes in evaluation, determination of new correlations, and optimization for material design. In this work, we show how a ML-based model can relate the properties (grain size, tensile yield stress, compressible yield stress, ultimate tensile strength, ultimate compressible strength, compressive and tensile strain under failure, hardness and texture) of indirectly extruded Mg-Gd alloys and the process parameters (extrusion velocity and temperature) with the alloy content of Gd between 0 % and 10 %. An ensemble based approach using shallow artificial neural networks was chosen to predict the material properties. A hyper parameter optimization process was used to obtain the lowest error. This machine learning approach allows defining objective functions to predict, among other factors, the anisotropic behaviour of Mg-Gd or the strengths. It is demonstrated how accurately the trained network predicts isotropic extruded alloys and process parameters, with the results checked against validation data. Validation data was obtained by uniaxial tensile and compression testing as well as optical microscopy of the extruded Mg-Gd alloys and is included. The ML based model is overall slightly better in predicting the material properties compared to a linear-regression approach. This approach allows a prediction of the relationship between process parameters, alloy content and properties in the development of this alloy system or comparable Mg systems. In the future, it will be possible to reduce the number of attempts needed to achieve a specific result or even for online quality monitoring. This approach is promising and needs to be evaluated for other systems with further data. %0 journal article %@ 1944-8244 %A Reimers, J., Trinh, H.C., Wiese, B., Meyer, S., Brehling, J., Flenner, S., Hagemann, J., Kruth, M., Kibkalo, L., Cwieka, H., Hindenlang, B., Lipinska-Chwalek, M., Mayer, J., Willumeit-Roemer, R., Greving, I., Zeller-Plumhoff, B. %D 2023 %J ACS Applied Materials and Interfaces %N 29 %P 35600-35610 %R doi:10.1021/acsami.3c04054 %T Development of a bioreactor-coupled flow-cell setup for 3D in situ nanotomography of Mg alloy biodegradation %U https://doi.org/10.1021/acsami.3c04054 29 %X Functional materials feature hierarchical microstructures that define their unique set of properties. The prediction and tailoring of these require a multiscale knowledge of the mechanistic interaction of microstructure and property. An important material in this respect is biodegradable magnesium alloys used for implant applications. To correlate the relationship between the microstructure and the nonlinear degradation process, high-resolution in situ three-dimensional (3D) imaging experiments must be performed. For this purpose, a novel experimental flow cell is presented which allows for the in situ 3D-nano imaging of the biodegradation process of materials with nominal resolutions below 100 nm using nanofocused hard X-ray radiation from a synchrotron source. The flow cell setup can operate under adjustable physiological and hydrodynamic conditions. As a model material, the biodegradation of thin Mg-4Ag wires in simulated body fluid under physiological conditions and a flow rate of 1 mL/min is studied. The use of two full-field nanotomographic imaging techniques, namely transmission X-ray microscopy and near-field holotomography, is compared, revealing holotomography as the superior imaging technique for this purpose. Additionally, the importance of maintaining physiological conditions is highlighted by the preliminary results. Supporting measurements using electron microscopy to investigate the chemical composition of the samples after degradation are performed. %0 editorial %@ 2073-4352 %A Wiese, B., Celikin, M., Mendis, C.L. %D 2023 %J Crystals %N 6 %P 882 %R doi:https://dx.doi.org/10.3390/cryst13060882 %T Relationships between Processing and Properties of Magnesium-Based Alloys %U https://doi.org/https://dx.doi.org/10.3390/cryst13060882 6 %X Magnesium alloys can be used in a wide range of applications, from lightweight structural and transport applications to biomaterials. The first step in designing a material is to identify a possible application and to derive the property profile for it. This is used to tailor the material and the processes for the production of a component. Different manufacturing processes have certain advantages and disadvantages in order to obtain the desired property profile of the material. Therefore, it is essential to know how the processing parameters affect the property profile of magnesium alloys. This understanding is important during the development and optimization of new materials on different process routes, as well as in the transfer to industrial processes and quality control. Therefore, the focus of this issue is on the relationship between processes and properties of magnesium-based alloys. Contributions are intended to show the influence of the manufacturing process, e.g., extrusion, rolling, heat treatment, Equal-Channel Angular Pressing (ECAP), and processing parameters, e.g., temperature, time, and cooling, on the property profile. This encompasses microstructural developments such as changes in grain size or texture, as well as mechanical properties, but also corrosion properties for mechanical engineering applications or degradation properties for medical applications. %0 journal article %@ 1751-6161 %A Steglich, D., Besson, J., Reinke, I., Helmholz, H., Luczak, M., Garamus, V.M., Wiese, B., Höche, D., Cyron, C.J., Willumeit-Römer, R. %D 2023 %J Journal of the Mechanical Behavior of Biomedical Materials %P 105939 %R doi:10.1016/j.jmbbm.2023.105939 %T Strength and Ductility Loss of Magnesium-Gadolinium due to Corrosion in Physiological Environment: Experiments and Modeling %U https://doi.org/10.1016/j.jmbbm.2023.105939 %X We propose a computational framework to study the effect of corrosion on the mechanical strength of magnesium (Mg) samples. Our work is motivated by the need to predict the residual strength of biomedical Mg implants after a given period of degradation in a physiological environment. To model corrosion, a mass-diffusion type model is used that accounts for localised corrosion using Weibull statistics. The overall mass loss is prescribed (e.g., based on experimental data). The mechanical behaviour of the Mg samples is modeled by a state-of-the-art Cazacu–Plunkett–Barlat plasticity model with a coupled damage model. This allowed us to study how Mg degradation in immersed samples reduces the mechanical strength over time. We performed a large number of in vitro corrosion experiments and mechanical tests to validate our computational framework. Our framework could predict both the experimentally observed loss of mechanical strength and the ductility due to corrosion for both tension and compression tests. %0 conference lecture %@ %A Petersen, N., Wiese, B., Hort, N. %D 2023 %J TMS 2023 Annual Meeting & Exhibition %T Barrel Finishing of Magnesium Alloys %U %X %0 conference paper %@ %A Petersen, N., Wiese, B., Hort, N. %D 2023 %J Magnesium Technology 2023. TMS 2023. The Minerals, Metals & Materials Series %P 101-106 %R doi:10.1007/978-3-031-22645-8_22 %T Barrel Finishing of Magnesium Alloys %U https://doi.org/10.1007/978-3-031-22645-8_22 %X Barrel finishing is a well-established process in the industry for the targeted machining of surfaces. Especially small parts in large quantities with simple geometries can be easily machined this way. When investigating the biological behaviour of degradable magnesium implant alloys, platelets of 1 cm diameter and a thickness of slightly more than one mm are often used. Due to statistical requirements, a higher number of pieces are necessary. In addition, the geometry is comparatively simple. To ensure a certain reproducibility, all samples should also have comparatively similar surfaces. In this work, different abrasives and various process parameters are investigated to answer the question of whether barrel grinding is a viable process for producing reproducible specimens. %0 conference lecture %@ %A Steglich, D., Besson, J., Reinke, I., Helmholz, H., Luczak, M., Garamus, V.M., Wiese, B., Höche, D., Cyron, C.J., Willumeit-Römer, R. %D 2023 %J Microstructural Mechanics meeting within the DGM expert committee Modelling, Simulation and Data %T Strength and Ductility Loss of Magnesium-Gadolinium due to Corrosion in Physiological Environment %U %X %0 journal article %@ 2374-068X %A Rafiei, S., Habibolahzadeh, A., Wiese, B. %D 2023 %J Advances in Materials and Processing Technologies %N 1 %P 32-46 %R doi:10.1080/2374068X.2022.2085364 %T Non-ignitable dilute Mg–0.36Al–1CaO (wt.%) alloy with high compressive strength %U https://doi.org/10.1080/2374068X.2022.2085364 1 %X The industrialisation of Mg alloys is hindered by low strength and ignitability. In this way, compressive strength is of prime interest, and unfortunately, commercial Mg castings have compressive yield strength less than 200 MPa. We have developed a non-ignitable Mg–0.36Al–1CaO (wt.%) alloy by ECO processing route that, despite its leanness (<1 wt.% total alloying content), has a compressive yield strength of higher than 200 MPa in all three different conditions of as-cast, T4, and peak-aged T6, showing the viability of both age hardening, and solid-solution strengthening accompanied by short-range order. The chemical analysis revealed that the reaction between 1 wt.% of added CaO and the melt led to ~0.4 wt.% alloyed Ca (Ca/Al mass ratio is ~1). The protective effect of alloyed Ca, enabled casting without extra protections (gases or salt) with no sign of ignition. Microstructural evolution was studied by SEM and EDS in conjunction with thermodynamic calculations. Comparison of the compressive yield strength of this alloy (in as-cast, T4, and peak-aged T6 conditions) with that of commercial alloys showed this alloy has the highest strength, with the added benefits of lower production costs and ignition resistance, bestowed by utilising cheap CaO. %0 conference lecture (invited) %@ %A Willumeit-Römer, R., Bruns, S., Helmholz, H., Krüger, D., Wiese, B., Galli, S., Moosmann, J., Zeller-Plumhoff, B. %D 2022 %J Magnesium Technology Symposium held at the TMS Annual Meeting and Exhibition %T The Comparability of In Vitro and In Vivo Experiments for Degradable Mg Implants %U %X %0 journal article %@ 2452-199X %A Krüger, D., Galli, S., Zeller-Plumhoff, B., Wieland, F., Peruzzi, N., Wiese, B., Heuser, P., Mossmann, J., Wennerberg, A., Willumeit-Römer, R. %D 2022 %J Bioactive Materials %P 37-52 %R doi:10.1016/j.bioactmat.2021.10.041 %T High-resolution ex vivo analysis of the degradation and osseointegration of Mg-xGd implant screws in 3D %U https://doi.org/10.1016/j.bioactmat.2021.10.041 %X Our results showed that Mg-5Gd degraded faster and less homogeneously than Mg-10Gd. Both alloys gradually form a stable degradation layer at the interface and were surrounded by new bone tissue. The results were correlated to in vitro data obtained from the same material and shape. The average bone-to-implant contact of the Mg-xGd implants was comparable to that of Ti and higher than for PEEK. The results suggest that both Mg-xGd alloys are suitable as materials for bone implants. %0 journal article %@ 0169-4332 %A Yao, X., Tang, J., Zhou, Y., Huang, Z., Xu, J., Long, Y., Tan, L., Wiese, B., Ebel, T., Yan, M. %D 2022 %J Applied Surface Science %P 152229 %R doi:10.1016/j.apsusc.2021.152229 %T Selective laser melting of an Mg/Metallic Glass hybrid for significantly improving chemical and mechanical performances %U https://doi.org/10.1016/j.apsusc.2021.152229 %X Pure magnesium (Mg) is widely used as biomedical material, but its degradation rate is often too high and problematic to clinic applications. In this study, selective laser melting (SLM) was used to prepare an Fe-based metallic glass surface on a pure Mg substrate, forming a hybrid material to explore the advantage associated with such designed structure. It was found that the corrosion resistance was significantly improved with the hybrid material (from 0.89 ± 0.1 mm/a to 0.11 ± 0.03 mm/a in simulated body fluid), along with much increased hardness from 0.46 GPa to 14.3 GPa. The metallic glass surface was shown to retain its amorphous nature after the SLM processing. The molten pool formed by the applied laser beam resulted in a good mechanically interlocked bonding between the metallic glass layer and the Mg matrix. It was further revealed that the metallic glass surface had better wetting property than the Mg substrate, explaining why the MG-63 cells had good adhesion to it. The cell toxicity test was followed under the in vitro condition, indicating no toxicity in the metallic glass part. The results provide a feasible way to develop advanced Mg materials for biomedical applications via the capable SLM technology and via the suggested hybrid material. %0 journal article %@ 2047-4849 %A Sun, Y., Helmholz, H., Will, O., Damm, T., Wiese, B., Luczak, M., Peschke, E., Luthringer-Feyerabend, B., Ebel, T., Hövener, J., Glüer, C., Willumeit-Römer, R. %D 2022 %J Biomaterials Science %N 6 %P 1532-1543 %R doi:10.1039/D2BM00051B %T Dynamic in vivo monitoring of fracture healing process in response to magnesium implant with multimodal imaging: Pilot longitudinal study in a rat external fixation model %U https://doi.org/10.1039/D2BM00051B 6 %X Rodent models are commonly used in pre-clinical research of magnesium (Mg) -based and other types of biomaterials for fracture treatment. Most studies selected unstable fixation methods, and there is a lack of multimodal longitudinal in vivo monitoring of bone healing. The purpose of this study is to develop a rat femoral fracture model stabilized by external fixation with intra-medullary Mg implant, and to investigate the dynamic bone union process with several imaging techniques offering complementing insights into the process. Pure Mg pins were prepared, followed by in vitro degradation test. Male Sprague-Dawley rats in the experimental group underwent femoral osteotomy stabilized by external fixators with intra-medullary implantation of Mg pins, and the control group underwent external fixation without intra-medullary implants. Post-operative radiograph, micro-CT and B-mode ultrasonography were acquired directly after surgery, and re-examined at week 4, 8 and 12. Bone tissue volume, in vivo implant degradation, histological staining and MRI images were analyzed using ex vivo samples. Both groups achieved fracture union at week 12, and the dynamic healing process was illustrated by in vivo radiograph, micro-CT and ultrasonography. Bilateral whole femur ex vivo analysis further demonstrated increased ratio of bone tissue volume in the surgical femur with Mg implants, and in vivo degradation of Mg pins was slower than in vitro results. Titanium screws rather than intra-medullary Mg pins were the source of artifact in MRI. This pilot study showed the rat fracture model with external fixation and intra-medullary Mg implantation, to be an effective method for dynamic in vivo monitoring of the bone healing process. Future application of the animal model may facilitate pre-clinical translational research of biodegradable orthopaedic implant materials for fracture treatment. %0 conference paper %@ %A Willumeit-Römer, R., Bruns, S., Helmholz, H., Krüger, D., Wiese, B., Galli, S., Moosmann, J., Zeller-Plumhoff, B. %D 2022 %J Magnesium Technology 2022 %P 9-16 %R doi:10.1007/978-3-030-92533-8_3 %T The Comparability of In Vitro and In Vivo Experiments for Degradable Mg Implants %U https://doi.org/10.1007/978-3-030-92533-8_3 %X Mg implants possess a great potential for clinical applications. Thousands of patients are already successfully treated with Mg implants and the number of approved products increases. Despite the fact that the implants generally work, we know that we have not yet reached a full understanding of all processes which occur during the degradation of the material and tissue regeneration. A prerequisite for a comprehensive description is the visualization and analysis of the in vivo processes with high resolution, while avoiding metal artefacts during imaging and taking care of different imaging properties of inorganic and organic matrices. Here, synchrotron radiation-based micro-computed tomography was utilized to determine the degradation rates for two implant materials (Mg-5Gd and Mg-10Gd, wt. %) in vitro and in vivo. The comparison for in vitro and in vivo degradation in terms of degradation rate and pitting factor shows that in vitro experiments predict in vivo results the error. As a second aspect, push-out experiments revealed a better integration into bone for Mg-10Gd and the improvement of implant stability over time. Finally, micro X-ray fluorescence spectrometry was applied to determine the elemental composition of degradation products around the Mg-5Gd specimen in vivo. This technique shows that the Mg content of the degrading specimen is decreasing while the Gd content stays constant. %0 journal article %@ 2073-4352 %A Wiese, B., Harmuth, J., Willumeit-Römer, R., Bohlen, J. %D 2022 %J Crystals %N 8 %P 1036 %R doi:10.3390/cryst12081036 %T Property Variation of Extruded Mg-Gd Alloys by Mn Addition and Processing %U https://doi.org/10.3390/cryst12081036 8 %X This paper presents how the mechanical properties, the microstructure and the degradation rate of extruded Mn-containing Mg-Gd alloys can be modified during extrusion. Gd as a rare earth element is particularly interesting due to the influence on the texture development in Mg, and is therefore studied as a base alloy system. The contents of Gd were investigated between 2 to 9 wt.%, with Mn additions of 0.5 and 1.0 wt.%. The grain sizes and the corresponding textures were modified by varying the extrusion parameters and the alloy content. It was shown that modification with Mn can lead to further grain refinement, an increase in the degree of recrystallization, as well as a decrease in the degradation rate in the biological medium compared with the binary Mg-Gd system from previous studies. The results suggest that the resulting properties are more robust compared with the binary alloy. %0 journal article %@ 1359-6462 %A Meyer, S., Wiese, B., Hort, N., Willumeit-Römer, R. %D 2022 %J Scripta Materialia %P 114712 %R doi:10.1016/j.scriptamat.2022.114712 %T Characterization of the deformation state of magnesium by electrical resistance %U https://doi.org/10.1016/j.scriptamat.2022.114712 %X Electrical resistance testing offers a fast and non-destructive method, which is very sensitive to microstructural features and crystal defects. The influence of the mechanically introduced strain, the alloy concentration and solution state as well as the grain size is shown and discussed based on cold-drawn magnesium wires containing 0.45, 0.91 and 1.42 at. silver. The condition of the material can be quantified by linear increase of 8.96 0.17 nm per unit strain and 6.58 0.06 nm/at. with silver content. This enables the classification of the deformation state and work hardening to push the process limits and allow adjusting the mechanical properties for their application. %0 conference lecture (invited) %@ %A Willumeit-Römer, R., Bruns, S., Helmholz, H., Hort, N., Krüger, D., Wiese, B., Galli, S., Moosmann, J., Cyron, C., Zeller-Plumhoff, B. %D 2022 %J ESB2022 32nd Annual Conference of the European Society for Biomaterials %T The comparability of in vitro and in vivo experiments for degradable Mg-implants: basis for a digital twin of implant degradation %U %X %0 conference lecture (invited) %@ %A Riekehr, S., Wiese, B., Odermatt, A., Ventzke, V., Kashaev, N. %D 2022 %J 2nd Global Summit on 3D Printing & Additive Manufacturing (3DPRINTING-2022) %T Laser directed energy deposition with wire of magnesium alloys with and without aluminium %U %X %0 conference poster %@ %A Meyer, S., Wiese, B., Hort, N., Willumeit-Römer, R. %D 2022 %J International Intelligent Materials 2022 %T Electrical resistivity testing %U %X %0 conference lecture %@ %A Reifenrath, J., Willumeit-Römer, R., Windhagen, H., Wiese, B., Mavila, B., Helmholz, H., Scheper, V., Angrisani, N. %D 2021 %J 13th Symposium on Biodegradable Metals for Biomedical Applications %T Implantation of pure magnesium beads in the subchondral bone plate to influence bone quality in osteoarthritic rabbits %U %X %0 journal article %@ 2213-9567 %A Nidadavolu, E., Krüger, D., Zeller-Plumhoff, B., Tolnai, D., Wiese, B., Feyerabend, F., Ebel, T., Willumeit-Römer, R. %D 2021 %J Journal of Magnesium and Alloys %N 2 %P 686-703 %R doi:10.1016/j.jma.2020.05.006 %T Pore characterization of PM Mg–0.6Ca alloy and its degradation behavior under physiological conditions %U https://doi.org/10.1016/j.jma.2020.05.006 2 %X Several material parameters affect degradation characteristics of Mg and its alloys under physiological conditions. Porous Mg materials are interesting for their simultaneous degradation and drug delivery capabilities. However, an increase in pore surface area is detrimental to both degradation resistance and subsequent mechanical properties. The present work aims at determining the threshold porosity value in Mg–0.6Ca specimens produced by powder metallurgy (PM) below which low degradation rates persist with acceptable mechanical properties. Seven different porous Mg–0.6Ca specimens containing both closed and open pore structures were fabricated with porosities ranging from 3% to 21%. Degradation profiles were obtained via a semi static immersion test over 16 days under physiological conditions using Dulbecco's modified Eagle's medium with Glutamax and 10% fetal bovine serum as supplements. The results are related to morphological pore parameters like pore size distribution, pore interconnectivity and pore curvatures that were quantified using an ex situ µCT analysis. In general, with decreasing porosity a decrease in pore interconnectivity is seen followed by rounding of the pores. Low degradation rates (MDR < 0.3 mm/year) are observed in specimens until 10% porosity, however, the upper bound for reproducible degradation is observed to be in specimens until 12% porosity. This porosity level also marks the transition from closed to open pore nature with a simultaneous change in pore interconnectivity from less than 10% to greater than 95%, below and above this porosity level, respectively. The tensile strength and elongation to failure recorded for specimens with 10% porosity were 70 MPa and 2%, respectively displaying positive traits of both homogenous degradation and mechanical properties. The results suggest that high pore interconnectivity is the dominant factor controlling degradation and mechanical properties in porous Mg-0.6Ca specimens. The results also indicate a good sintering response of Mg-0.6Ca specimens providing further material development towards biomaterial applications. %0 journal article %@ 2213-9567 %A Wiese, B., Willumeit-Römer, R., Letzig, D., Bohlen, J. %D 2021 %J Journal of Magnesium and Alloys %N 1 %P 112-122 %R doi:10.1016/j.jma.2020.08.001 %T Alloying effect of silver in magnesium on the development of microstructure and mechanical properties by indirect extrusion %U https://doi.org/10.1016/j.jma.2020.08.001 1 %X The effect of Ag in solid solution on the microstructure, texture and the deformation behaviour of indirectly extruded Mg was investigated. Ag as a solid solution strengthener affects the behaviour during extrusion, resulting in enhanced deformation related heating and corresponding coarser grained microstructures. No substantial effect on the texture development is revealed. The mechanical properties simultaneously increase in stress and strain levels with increasing Ag content, especially in tension as a result of the changing impact of the slip modes which can be associated with a decrease of the lattice parameters as well as the c/a ratio of the hcp lattice structure. In compression tests with twin dominated flow, the impact is much smaller on the compressive yield stress but higher with respect to the twinning related strain hardening rate. Solid solution strength functions for Fleischer and Labusch were determined, also confirming the anisotropic behaviour of the extruded Mg alloys. %0 journal article %@ 2213-9567 %A Yao, X., Tang, J., Zhou, Y., Atrens, A., Dargusch, M., Wiese, B., Ebel, T., Yan, M. %D 2021 %J Journal of Magnesium and Alloys %N 6 %P 2155-2168 %R doi:10.1016/j.jma.2020.08.011 %T Surface modification of biomedical Mg-Ca and Mg-Zn-Ca alloys using selective laser melting: Corrosion behaviour, microhardness and biocompatibility %U https://doi.org/10.1016/j.jma.2020.08.011 6 %X Magnesium alloys such as Mg–Ca and Mg–Zn–Ca are good orthopaedic materials; however their tendency to corrode is high. Herein we utilize selective laser melting (SLM) to modify the surface of these Mg alloys to simultaneously improve the corrosion behaviour and microhardness. The corrosion rate decreased from 2.1 ± 0.2 mm/y to 1.0 ± 0.1 mm/y for the laser-processed Mg–0.6Ca, and from 1.6 ± 0.1 mm/y to 0.7 ± 0.2 mm/y for laser-processed Mg–0.5Zn–0.3Ca. The microhardness increased from 46 ± 1 HV to 56 ± 1 HV for Mg–0.6Ca, and from 47 ± 3 HV to 55 ± 3 HV for Mg–0.5Zn–0.3Ca. In addition, good biocompatibility remained in the laser processed Mg alloys. The improved properties are attributed to laser-induced grain refinement, confined impurity elements, residual stress, and modified surface chemistry. The results demonstrated the potential of SLM as a surface engineering approach for developing advanced biomedical Mg alloys. %0 journal article %@ 0010-938X %A Zeller-Plumhoff, B., Gile, M., Priebe, M., Slominska, H., Boll, B., Wiese, B., Würger, T., Willumeit-Römer, R., Meißner, R. %D 2021 %J Corrosion Science %P 109272 %R doi:10.1016/j.corsci.2021.109272 %T Exploring key ionic interactions for magnesium degradation in simulated body fluid – A data-driven approach %U https://doi.org/10.1016/j.corsci.2021.109272 %X We have studied the degradation of pure magnesium wire in simulated body fluid and its subsets under physiological conditions to enable the prediction of the degradation rate based on the medium's ionic composition. To this end, micro-computed tomography and scanning electron microscopy with energy-dispersive X-ray spectroscopy were used, followed by a tree regression analysis. A non-linear relationship was found between degradation rate and the precipitation of calcium salts. The mean absolute error for predicting the degradation rate was 1.35 mm/yr. This comparatively high value indicates that ionic interactions were exceedingly complex or that an unknown parameter determining the degradation may exist. %0 journal article %@ 1005-0302 %A Jin, Y., Blawert, C., Hang, H., Wiese, B., Bohlen, J., Mei, D., Deng, M., Feyerabend, F., Willumeit, R. %D 2021 %J Journal of Materials Science & Technology %P 214-224 %R doi:10.1016/j.jmst.2021.04.005 %T Deteriorated corrosion performance of micro-alloyed Mg-Zn alloy after heat treatment and mechanical processing %U https://doi.org/10.1016/j.jmst.2021.04.005 %X The corrosion performances of the as-cast and solution-treated Mg-0.5Zn samples were investigated in 0.9% NaCl solution and compared. From the electrochemical measurement results and corrosion morphology observations, it is found that the corrosion resistance of Mg-0.5Zn deteriorated with the extension of solution treatment duration. The main reason was the formation of Fe-Si precipitates with higher Fe concentrations during heat treatment. The Fe-Si precipitates, especially the ones with high Fe contents influenced the corrosion initiation and propagation significantly. In regard of corrosion performance, the solution-treated and then extruded sample was also performing not as good as the cast and then directly extruded sample. %0 journal article %@ 1473-2262 %A Angrisani, N., Willumeit-Römer, R., Windhagen, H., Mavila Chathoth, B., Scheper, V., Wiese, B., Helmholz, H., Reifenrath, J. %D 2021 %J European Cells & Materials %P 179-195 %R doi:10.22203/eCM.v042a14 %T Small-sized magnesium cylinders influence subchondral bone quality in osteoarthritic rabbits - an in vivo pilot study %U https://doi.org/10.22203/eCM.v042a14 %X No optimal therapy exists to stop or cure chondral degeneration in osteoarthritis (OA). While the pathogenesis is unclear, there is consensus on the etiological involvement of both articular cartilage and subchondral bone. Compared to original bone, the substance of sclerotic bone is mechanically less solid. The osteoproliferative effect of Mg has been shown repeatedly during development of Mg-based osteosynthesis implants. The aim of the present study was to examine the influence of implanted high-purity Mg cylinders on subchondral bone quality in a rabbit OA model. 10 New Zealand White rabbits received into the knee either 20 empty drill holes or 20 drill holes, which were additionally filled with one Mg cylinder each. Follow-up was at 8 weeks. Micro-computed tomography (µCT) was performed. After euthanasia, cartilage condition was determined, bone samples were collected and processed for histological evaluation and elemental imaging by micro-X-ray fluorescence spectrometry (µXRF). Articular cartilage collected post-mortem showed different stages of lesions, from mild alterations up to exposed subchondral bone, which tended to be slightly lower in animals with implanted Mg cylinders. µCT showed significantly increased bone volume in the Mg group. Also, histological evaluation revealed distinct differences. While right, operated limbs did not show any significant difference, left, non-operated controls showed significantly less changes in articular cartilage in the Mg group. A distinct influence of implanted cylinders of pure Mg on subchondral bone of osteoarthritic rabbits was shown. Subsequent evaluations, including other time points and alternative alloys, will show if this could alter OA progression. %0 conference lecture %@ %A Meyer, S., Wiese, B., Ebel, T., Willumeit-Römer, R. %D 2021 %J 13th Biometal 2021 %T Grain refinement in cold drawn Mg-xAg wires %U %X %0 journal article %@ 2075-4701 %A Meyer, S., Wolf, A., Sanders, D., Iskhakova, K., Ćwieka, H., Bruns, S., Flenner, S., Greving, I., Hagemann, J., Willumeit-Römer, R., Wiese, B., Zeller-Plumhoff, B. %D 2021 %J Metals %N 9 %P 1422 %R doi:10.3390/met11091422 %T Degradation Analysis of Thin Mg-xAg Wires Using X-ray Near-Field Holotomography %U https://doi.org/10.3390/met11091422 9 %X Magnesium–silver alloys are of high interest for the use as temporary bone implants due to their antibacterial properties in addition to biocompatibility and biodegradability. Thin wires in particular can be used for scaffolding, but the determination of their degradation rate and homogeneity using traditional methods is difficult. Therefore, we have employed 3D imaging using X-ray near-field holotomography with sub-micrometer resolution to study the degradation of thin (250 μm diameter) Mg-2Ag and Mg-6Ag wires. The wires were studied in two states, recrystallized and solution annealed to assess the influence of Ag content and precipitates on the degradation. Imaging was employed after degradation in Dulbecco’s modified Eagle’s medium and 10% fetal bovine serum after 1 to 7 days. At 3 days of immersion the degradation rates of both alloys in both states were similar, but at 7 days higher silver content and solution annealing lead to decreased degradation rates. The opposite was observed for the pitting factor. Overall, the standard deviation of the determined parameters was high, owing to the relatively small field of view during imaging and high degradation inhomogeneity of the samples. Nevertheless, Mg-6Ag in the solution annealed state emerges as a potential material for thin wire manufacturing for implants. %0 conference lecture %@ %A Wiese, B., Meyer, S., Sanders, D., Ebel, T., Willumeit-Römer, R. %D 2021 %J 13th Symposium on Biodegradable Metals for Biomedical Applications %T Mechanical properties of Mg-Ag wires with 2; 4 and 6 wt.% Ag %U %X %0 journal article %@ 2213-9567 %A Krüger, D., Zeller-Plumhoff, B., Wiese, B., Yi, S., Zuber, M., Wieland, F., Moosmann, J., Willumeit-Römer, R. %D 2021 %J Journal of Magnesium and Alloys %N 6 %P 2207-2222 %R doi:10.1016/j.jma.2021.07.029 %T Assessing the microstructure and in vitro degradation behavior of Mg-xGd screw implants using µCT %U https://doi.org/10.1016/j.jma.2021.07.029 6 %X Although differences were observed in the degree of screw's near surface microstructure being influenced from machining, the degradation rates of both materials appeared to be suitable for application in orthopedic implants. From the degradation homogeneity point of view no obvious contrast was detected between both alloys. However, the higher degradation depth ratios between the crests and roots of Mg-5Gd ratios may indicated a less homogeneous degradation of the screws of these alloys on contract to the ones made of Mg-10Gd alloys. Due to its lower degradation rates, its more homogeneous microstructure, its weaker texture and better degradation performance extruded Mg-10Gd emerged more suitable as implant material than Mg-5Gd. %0 conference lecture %@ %A Wiese, B. %D 2021 %J IMA-Webinar: Magnesium Medical Applications — End-Product Focus %T Magnesium - More than a load-bearing implant %U %X %0 conference poster %@ %A Mavila, B., Helmholz, H., Wiese, B., Angrisain, N., Luthringer-Feyerabend, B., Willumeit-Römer, R. %D 2021 %J Euromat 2021 %T Mg-based microparticles (beads) as potential therapeutics for Osteoarthritis %U %X %0 conference lecture %@ %A Meyer, S., Wiese, B., Bohlen, J., Ebel, T., Willumeit-Römer, R. %D 2020 %J Updates in Bioabsorbable Metals 2020 %T The grain refinement effect of gadolinium in magnesium at modified extrusion ratio %U %X %0 journal article %@ 0264-1275 %A Jin, Y., Blawert, C., Yang, H., Wiese, B., Feyerabend, F., Bohlen, J., Mei, D., Deng, M., Silva Campos, M., Scharnagl, N., Strecker, K., Bode, J., Vogt, C., Willumeit-Römer, R. %D 2020 %J Materials and Design %P 108980 %R doi:10.1016/j.matdes.2020.108980 %T Microstructure-corrosion behaviour relationship of micro-alloyed Mg-0.5Zn alloy with the addition of Ca, Sr, Ag, In and Cu %U https://doi.org/10.1016/j.matdes.2020.108980 %X The effects of micro-addition (0.2 wt.%) of Ca, Sr, Ag, In and Cu on the microstructure and corrosion properties of the as-cast Mg-0.5Zn alloy were systematically studied. It is found that the grain refinement efficiency and intermetallics forming ability differed greatly among these elements. Si impurity also played a vital role in the precipitates formation in all systems. It is generally observed that Mg-Zn-Ca possessed the highest corrosion resistance due to the refined grain size, limited intermetallics and uniform corrosion, whereas Mg-Zn-Cu showed the highest corrosion rate due to the coarse grains, intermetallics activity and severe pitting corrosion. With the exception of Mg-Zn-Cu, the corrosion performances of Mg-0.5Zn(-0.2X) alloys were comparable with the higher concentrated systems from literature, indicating the feasibility of these micro-alloying systems for biomedical applications. %0 journal article %@ 1996-1944 %A Bohlen, J., Meyer, S., Wiese, B., Luthringer-Feyerabend, B.J.C., Willumeit-Römer, R., Letzig, D. %D 2020 %J Materials %N 2 %P 391 %R doi:10.3390/ma13020391 %T Alloying and Processing Effects on the Microstructure, Mechanical Properties, and Degradation Behavior of Extruded Magnesium Alloys Containing Calcium, Cerium, or Silver %U https://doi.org/10.3390/ma13020391 2 %X Magnesium alloys attract attention as degradable implant materials due to their adjustable corrosion properties and biocompatibility. In the last few decades, especially wrought magnesium alloys with enhanced mechanical properties have been developed, with the main aim of increasing ductility and formability. Alloying and processing studies allowed demonstrating the relationship between the processing and the microstructure development for many new magnesium alloys. Based on this experience, magnesium alloy compositions need adjustment to elements improving mechanical properties while being suitable for biomaterial applications. In this work, magnesium alloys from two Mg-Zn series with Ce (ZE) or Ca (ZX) as additional elements and a series of alloys with Ag and Ca (QX) as alloying elements are suggested. The microstructure development was studied after the extrusion of round bars with varied processing parameters and was related to the mechanical properties and the degradation behavior of the alloys. Grain refinement and texture weakening mechanisms could be improved based on the alloy composition for enhancing the mechanical properties. Degradation rates largely depended on the nature of second phase particles rather than on the grain size, but remained suitable for biological applications. Furthermore, all alloy compositions exhibited promising cytocompatibility. %0 journal article %@ 1742-7061 %A Zeller-Plumhoff, B., Malich, C., Krueger, D., Campbell, G., Wiese, B., Galli, S., Wennerberg, A., Willumeit-Römer, R., Wieland, D.C.F. %D 2020 %J Acta Biomaterialia %P 637-645 %R doi:10.1016/j.actbio.2019.11.030 %T Analysis of the bone ultrastructure around biodegradable Mg–xGd implants using small angle X-ray scattering and X-ray diffraction %U https://doi.org/10.1016/j.actbio.2019.11.030 %X Magnesium alloys are increasingly researched as temporary biodegradable metal implants in bone applications due to their mechanical properties which are more similar to bone than conventional implant metals and the fact that Magnesium occurs naturally within the body. However, the degradation processes in vivo and in particular the interaction of the bone with the degrading material need to be further investigated. In this study we are presenting the first quantitative comparison of the bone ultrastructure formed at the interface of biodegradable Mg–5Gd and Mg–10Gd implants and titanium and PEEK implants after 4, 8 and 12 weeks healing time using two-dimensional small angle X-ray scattering and X-ray diffraction. Differences in mineralization, orientation and thickness of the hydroxyapatite are assessed. We find statistically significant (p < 0.05) differences for the lattice spacing of the (310)-reflex of hydroxyapatite between titanium and Mg–xGd materials, as well as for the (310) crystal size between titanium and Mg–5Gd, indicating a possible deposition of Mg within the bone matrix. The (310) lattice spacing and crystallite size further differ significantly between implant degradation layer and surrounding bone (p < 0.001 for Mg–10Gd), suggesting apatite formation with significant amounts of Gd and Mg within the degradation layer. %0 conference poster %@ %A Jin, Y., Feyerabend, F., Blawert, C., Bohlen, J., Wiese, B., Willumeit-Roemer, R. %D 2019 %J 11th Symposium on Biodegradable Metals, Biometal 2019 %T Microstructure of a Si contaminated Mg-Zn-Ca alloy and the corrosion behaviour observation via an in-situ approach %U %X %0 journal article %@ 2075-4701 %A Gawlik, M.M., Wiese, B., Welle, A., Gonzalez, J., Desharnais, V., Harmuth, J., Ebel, T., Willumeit-Roemer, R. %D 2019 %J Metals %N 2 %P 117 %R doi:10.3390/met9020117 %T Acetic Acid Etching of Mg-xGd Alloys %U https://doi.org/10.3390/met9020117 2 %X Mg-xGd alloys show potential to be used for degradable implants. As rare earth containing alloys, they are also of special interest for wrought products. All applications from medical to engineering uses require a low and controlled degradation or corrosion rate without pitting. Impurities from fabrication or machining, like Fe inclusions, encourage pitting, which inhibits uniform material degradation. This work investigates a suitable etching method to remove surface contamination and to understand the influence of etching on surface morphology. Acetic acid (HAc) etching as chemical surface treatment has been used to remove contamination from the surface. Extruded Mg-xGd (x = 2, 5 and 10) discs were etched with 250 g/L HAc solution in a volume of 5 mL or 10 mL for different times. The microstructure in the near surface region was characterized. Surface characterization was done by SEM, EDS, interferometry, and ToF-SIMS (time-of-flight secondary ion mass spectrometry) analysis. Different etching kinetics were observed due to microstructure and the volume of etching solution. Gd rich particles and higher etching temperatures due to smaller etchant volumes promote the formation of pits. Removal of 2–9 µm of material from the surface was sufficient to remove surface Fe contamination and to result in a plain surface morphology. %0 journal article %@ 0010-938X %A Jin, Y., Blawert, C., Feyerabend, F., Bohlen, J., Silva Campos, M., Gavras, S., Wiese, B., Mei, D., Deng, M., Yang, H., Willumeit-Roemer, R. %D 2019 %J Corrosion Science %P 108096 %R doi:10.1016/j.corsci.2019.108096 %T Time-sequential corrosion behaviour observation of micro-alloyed Mg-0.5Zn-0.2Ca alloy via a quasi-in situ approach %U https://doi.org/10.1016/j.corsci.2019.108096 %X The corrosion behaviour of as-cast and solution-annealed Mg-0.5Zn-0.2Ca alloy containing 150 ppm Si was investigated in 0.9% NaCl solution. The main secondary phases in the as-cast state are isolated MgCaSi and a coexisting intermetallic particle which consists of Mg2Ca and Ca2Mg6Zn3. A quasi-in situ approach is applied to investigate the corrosion initiation and development. It is proved that Mg2Ca phase is anodic and preferentially corrodes within the first hour of immersion. Whereas, Ca2Mg6Zn3 and MgCaSi phases continuously act as cathodes until 24 h. After solution annealing, the more homogeneous microstructure and reduced galvanic corrosion result in a higher corrosion resistance. %0 conference poster %@ %A Gawlik, M.M., Ebel, T., Willumeit-Roemer, R., Wiese, B. %D 2019 %J 11th Symposium on Biodegradable Metals, Biometal 2019 %T Impact of etching on the degradation of Mg-Gd alloys %U %X %0 conference object %@ %A Gawlik, M.M., Ebel, T., Willumeit-Roemer, R., Wiese, B. %D 2019 %J Abstract Book, 11th Symposium on Biodegradable Metals, Biometal 2019 %P Cor-17 %T Impact of etching on the degradation of Mg-Gd alloys %U %X %0 journal article %@ 1996-1944 %A Estrin, Y., Martynenko, N., Anisimova, N., Temralieva, D., Kiselevskiy, M., Serebryany, V., Raab, G., Straumal, B., Wiese, B., Willumeit-Römer, R., Dobatkin, S. %D 2019 %J Materials %N 23 %P 3832 %R doi:10.3390/ma12233832 %T The Effect of Equal-Channel Angular Pressing on the Microstructure, the Mechanical and Corrosion Properties and the Anti-Tumor Activity of Magnesium Alloyed with Silver %U https://doi.org/10.3390/ma12233832 23 %X The effect of equal-channel angular pressing (ECAP) on the microstructure, texture, mechanical properties, corrosion resistance and cytotoxicity of two magnesium-silver alloys, Mg-2.0%Ag and Mg-4.0%Ag, was studied. Their average grain size was found to be reduced to 3.2 ± 1.4 μm and 2.8 ± 1.3 μm, respectively. Despite the substantial grain refinement, a drop in the strength characteristics of the alloys was observed, which can be attributed to the formation of inclined basal texture. On a positive side, an increase in tensile ductility to ~34% for Mg-2.0%Ag and ~27% for Mg-4.0%Ag was observed. This effect can be associated with the activity of basal and prismatic slip induced by ECAP. One of the ECAP regimes tested gave rise to a drop in the corrosion resistance of both alloys. An interesting observation was a cytotoxic effect both alloys had on tumor cells in vitro. This effect was accompanied with the release of lactate dehydrogenase, an increase in oxidative stress, coupled with the induction of NO-ions and an increase in the content of such markers of apoptosis as Annexin V and Caspase 3/7. Differences in the chemical composition and the processing history-dependent microstructure of the alloys did not have any significant effect on the magnitude of their antiproliferative effect. %0 conference object %@ %A Jin, Y., Feyerabend, F., Blawert, C., Bohlen, J., Wiese, B., Willumeit-Roemer, R. %D 2019 %J Abstract Book, 11th Symposium on Biodegradable Metals, Biometal 2019 %P Cor-7 %T Microstructure of a Si contaminated Mg-Zn-Ca alloy and the corrosion behaviour observation via an in-situ approach %U %X %0 conference lecture %@ %A Wiese, B., Ebel, T., Willumeit-Römer, R. %D 2019 %J 37. Arbeitskreis Magnesium %T Medizinisches Magnesium: Ein aktueller Überblick %U %X %0 journal article %@ 0924-0136 %A Schaper, J.G., Wolff, M., Wiese, B., Ebel, T., Willumeit-Römer, R. %D 2019 %J Journal of Materials Processing Technology %P 241-246 %R doi:10.1016/j.jmatprotec.2018.12.015 %T Powder metal injection moulding and heat treatment of AZ81 Mg alloy %U https://doi.org/10.1016/j.jmatprotec.2018.12.015 %X Ongoing research has proven that Mg alloys can be introduced into the metal injection moulding process for the production of small parts in high quantities and of complex shape for medical as well as lightweight applications. Previously, development studies have been conducted using Mg and Mg-Ca alloys intended for medical application. However, progress towards the implementation of a process for technical and lightweight applications alloys with higher strength is needed. Therefore, in this study processing of conventional AZ81 alloy by MIM was successfully developed. Using this alloy, a yield strength of approximately 120 MPa and an ultimate tensile strength of approximately 255 MPa with elongation at fracture of approximately 7% was achieved. T4 heat treatment at 420 °C for 10 h does not reveal a positive influence on the mechanical properties this could be caused by an observed grain growth effect. This is in contrast to conventional material for example as cast, where T4 heat treatment is known to improve the mechanical properties especially elongation at fracture. %0 journal article %@ 2296-8016 %A Harmuth, J., Wiese, B., Bohlen, J., Ebel, T., Willumeit-Römer, R. %D 2019 %J Frontiers in Materials %P 201 %R doi:10.3389/fmats.2019.00201 %T Wide Range Mechanical Customization of Mg-Gd Alloys With Low Degradation Rates by Extrusion %U https://doi.org/10.3389/fmats.2019.00201 %X Currently, only a few magnesium alloys have been approved for implant applications. For biomedical purposes, the choice of the alloying elements is a critical parameter and rare earth elements have been proven to be mechanically suitable and biologically tolerable. In this comprehensive study, tailoring the mechanical properties of binary Mg-Gd alloys by indirect extrusion is shown to obtain a property profile that is applicable to different biomedical applications. Mg-2Gd, Mg-5Gd, and Mg-10Gd were solid solution treated before extrusion. For each alloy various combinations of extrusion temperature and speed were applied. Resulting effects of alloy composition and processing on microstructure development, texture evolution, mechanical properties, and degradation behavior were investigated. Grain sizes and corresponding textures were adjusted by the extrusion parameters. Despite changes in the texture, grain boundary strengthening effects were confirmed for all alloys in accordance with the Hall-Petch relationship. The alloy composition contributed to the mechanical properties by solid solution strengthening and a combination of texture changes and slip activities. Consequently, mechanical properties can be tailored within a wide range resulting in tensile yield strengths of 90 to 200 MPa (ultimate tensile strengths 180–280 MPa) and compressive yield strengths of 80 to 220 MPa (ultimate compressive strengths 300–450 MPa) with elongations of 10–45%. Low degradation rates in the range of 0.2 mm/year were determined for all alloys. Degradation was only slightly influenced by the alloy composition but not affected by processing. Overall, the properties of Mg-Gd determined in this work appear to be suitable to future implant applications. %0 conference paper %@ %A Willumeit-Roemer, R., Moosmann, J., Zeller-Plumhoff, B., Wieland, D.C.F., Krueger, D., Wiese, B., Wennerberg, A., Peruzzi, N., Galli, S., Beckmann, F., Hammel, J.U. %D 2018 %J TMS 2018, 147th Annual Meeting & Exhibition, Supplemental Proceedings %P 275-284 %R doi:10.1007/978-3-319-72526-0_25 %T Visualization of Implant Failure by Synchrotron Tomography %U https://doi.org/10.1007/978-3-319-72526-0_25 %X Here we present first data from an in situ tomography experiment of a biodegradable Mg-based implant under compressive load showing how Mg implants are incorporated into bone. %0 journal article %@ 2452-199X %A Wolff, M., Luczak, M., Schaper, J.G., Wiese, B., Dahms, M., Ebel, T., Willumeit-Roemer, R., Klassen, T. %D 2018 %J Bioactive Materials %N 3 %P 213-217 %R doi:10.1016/j.bioactmat.2018.03.002 %T In vitro biodegradation testing of Mg-alloy EZK400 and manufacturing of implant prototypes using PM (powder metallurgy) methods %U https://doi.org/10.1016/j.bioactmat.2018.03.002 3 %X The study is focussing towards Metal Injection Moulding (MIM) of Mg-alloys for biomedical implant applications. Especially the influence of the sintering processing necessary for the consolidation of the finished part is in focus of this study. In doing so, the chosen high strength EZK400 Mg-alloy powder material was sintered using different sintering support bottom plate materials to evaluate the possibility of iron impurity pick up during sintering. It can be shown that iron pick up took place from the steel bottom plate into the specimen. Despite the fact that a separating boron nitrite (BN) barrier layer was used and the Mg-Fe phase diagram is not predicting any significant solubility to each other. As a result of this study a new bottom plate material not harming the sintering and the biodegradation performance of the as sintered material, namely a carbon plate material, was found. %0 conference lecture (invited) %@ %A Letzig, D., Bohlen, J., Wiese, B., Wolff, M., Willumeit-Roemer, R. %D 2018 %J 11th International Conference on Magnesium Alloys and Their Applications, Mg 2018 %T From simple to very complex Mg implants: different processing routes for Ca containing Mg-alloys %U %X %0 conference lecture (invited) %@ %A Willumeit-Roemer, R., Moosmann, J., Zeller-Plumhoff, B., Wieland, D.C.F., Krueger, D., Wiese, B., Wennerberg, A., Peruzzi, N., Galli, S., Beckmann, F., Hammel, J.U. %D 2018 %J 10th International Conference on Processing and Manufacturing of Advanced Materials, THERMEC 2018 %T Magnesium as biodegradable implant materials: how does the interface react to load? %U %X %0 conference poster %@ %A Rafiei, S., Habibollahzadeh, A., Wiese, B. %D 2018 %J 7th International Conference on Materials Engineering and Metallurgy, iMat 2018 %T An Insight into Environment-Conscious (ECO) Magnesium: A Review %U %X %0 conference object %@ 2522-235X %A Jin, Y., Wiese, B., Feyerabend, F., Blawert, C., Bohlen, J., Willumeit-Roemer, R. %D 2018 %J eCells and Materials - eCM Conferences %P 10 %T Micro-alloying of Mg-Zn based alloys-Influence on corrosion behaviour %U %X No abstract %0 journal article %@ 1996-1944 %A Gawlik, M.M., Wiese, B., Desharnais, V., Ebel, T., Willumeit-Roemer, R. %D 2018 %J Materials %N 12 %P 2561 %R doi:10.3390/ma11122561 %T The Effect of Surface Treatments on the Degradation of Biomedical Mg Alloys - A Review Paper %U https://doi.org/10.3390/ma11122561 12 %X This report reviews the effects of chemical, physical, and mechanical surface treatments on the degradation behavior of Mg alloys via their influence on the roughness and surface morphology. Many studies have been focused on technically-used AZ alloys and a few investigations regarding the surface treatment of biodegradable and Al-free Mg alloys, especially under physiological conditions. These treatments tailor the surface roughness, homogenize the morphology, and decrease the degradation rate of the alloys. Conversely, there have also been reports which showed that rough surfaces lead to less pitting and good cell adherence. Besides roughness, there are many other parameters which are much more important than roughness when regarding the degradation behavior of an alloy. These studies, which indicate the relationship between surface treatments, roughness and degradation, require further elaboration, particularly for biomedical Mg alloy applications. %0 conference poster %@ %A Harmuth, J., Wiese, B., Bohlen, J., Ebel, T., Willumeit-Roemer, R. %D 2018 %J 11th International Conference on Magnesium Alloys and Their Applications, Mg 2018 %T Tailoring of material properties of Mg-Gd alloys for biomedical applications %U %X %0 conference paper %@ %A Harmuth, J., Wiese, B., Bohlen, J., Ebel, T., Willumeit-Roemer, R. %D 2018 %J Magnesium 2018, Proceedings of the 11th International Conference on Magnesium Alloys and Their Applications %P 376-381 %T Tailoring of material properties of Mg-Gd alloys for biomedical applications %U %X %0 conference lecture %@ %A Harmuth, J., Wiese, B., Bohlen, J., Ebel, T., Willumeit-Roemer, R. %D 2018 %J 10th Symposium on Biodegradable Metals for Biomedical Applications, BIOMETAL 2018 %T Suitability of as extruded Mg-Gd-0.5Mn for biomedical applications %U %X %0 conference object %@ %A Harmuth, J., Wiese, B., Bohlen, J., Ebel, T., Willumeit-Roemer, R. %D 2018 %J Abstract Book of 10th Symposium on Biodegradable Metals for Biomedical Applications, BIOMETAL 2018 %P Met-2 %T Suitability of as extruded Mg-Gd-0.5Mn for biomedical applications %U %X %0 conference object %@ 2522-235X %A Harmuth, J., Wiese, B., Bohlen, J., Ebel, T., Willumeit-Roemer, R. %D 2018 %J eCells and Materials - eCM Conferences %P 2 %T Suitability of as extruded Mg-Gd-0.5Mn for biomedical applications %U %X No abstract %0 conference paper %@ %A Rafiei, S., Habibollahzadeh, A., Wiese, B. %D 2018 %J Proceedings of 7th International Conference on Materials Engineering and Metallurgy, IMAT 2018 %P IMES12_010 %T An Insight into Environment-Conscious (ECO) Magnesium: A Review %U %X Magnesium (Mg) is the lightest metallic structural material and the urge to reduce the weight of vehicles and improving fuel efficiency has inevitably resulted in the long-time exposure of Mg alloys to elevated temperatures (above 200 ℃). Calcium (Ca) addition has been considered as cheap and practical solution to overcome high reactivity and ignition risks of Mg and its alloys. Besides, Ca-bearing Mg alloys are capable of air casting. The recently-developed Environment-conscious (ECO) manufacturing route is novel method of Ca addition, which utilizes CaO to produce Ca-containing Mg alloys and it is thermodynamically proved that this reaction is possible. Elemental calcium is very reactive and needs special requirements in terms of handling. On the other hand, CaO is much cheaper than Ca and can be handled safely due to its good stability. It is also proved that CaO-added Mg has higher melt fluidity than its Ca-added counterpart. The retarded oxidation and ignition of Ca-bearing Mg are reported to be the outcome of dense oxide film made up of CaO and MgO. This report provides comprehensive review of the current literature regarding high-temperature oxidation of Ca-bearing Mg and its alloys. Because commercial Mg casting alloys are mostly based on the Mg-Al system the effect of Aluminum (Al) on ignition and oxidation has also been reviewed. %0 conference poster %@ %A Jin, Y., Wiese, B., Feyerabend, F., Blawert, C., Bohlen, J., Willumeit-Roemer, R. %D 2018 %J 10th Symposium on Biodegradable Metals for Biomedical Applications, BIOMETAL 2018 %T Micro-alloying of Mg-Zn based alloys-Influence on corrosion behaviour %U %X %0 conference object %@ %A Jin, Y., Wiese, B., Feyerabend, F., Blawert, C., Bohlen, J., Willumeit-Roemer, R. %D 2018 %J Abstract Book of 10th Symposium on Biodegradable Metals for Biomedical Applications, BIOMETAL 2018 %P Met-10 %T Micro-alloying of Mg-Zn based alloys-Influence on corrosion behaviour %U %X %0 conference lecture %@ %A Willumeit-Roemer, R., Moosmann, J., Zeller-Plumhoff, B., Wieland, D.C.F., Krueger, D., Wiese, B., Wennerberg, A., Peruzzi, N., Galli, S., Beckmann, F., Hammel, J.U. %D 2018 %J 147th Annual Meeting & Exhibition, TMS 2018 %T Visualization of Implant Failure by Synchrotron Tomography %U %X %0 conference poster %@ %A Gawlik, M.M., Steiner, M., Wiese, B., Dahms, M., Ebel, T., Willumeit-Roemer, R. %D 2017 %J European Symposium and Exhibition on Biomaterials and Related Areas, EuroBioMat 2017 %T The effect of HAc etching on the degradation behaviour of Mg-5Gd %U %X %0 conference poster %@ %A Harmuth, J., Wiese, B., Bohlen, J., Ebel, T., Willumeit-Roemer, R. %D 2017 %J 9th Symposium on Biodegradable Metals, Biometall 2017 %T Influence of extrusion parameters on Mg-10Gd %U %X %0 journal article %@ 2366-9136 %A Gawlik, M.M., Steiner, M., Wiese, B., Gonzalez, J., Feyerabend, F., Dahms, M., Ebel, T., Willumeit-Roemer, R. %D 2017 %J Journal of Medical Materials and Technologies %N 2 %P 22-25 %R doi:10.24354/medmat.v1i2.17 %T The Effects of HAc Etching on the Degradation Behavior of Mg-5Gd %U https://doi.org/10.24354/medmat.v1i2.17 2 %X The effects of different acetic acid (HAc) etching procedures were investigated using Mg-5Gd samples in as-extruded and T4 conditions in order to achieve defined surfaces and homogenous degradation behavior. Samples were dipped into HAc solution with five different concentrations for three durations. In total, fifteen different etching conditions were tested with regard to the degradation resistance in physiological solution. The cell culture medium consisted of Dulbecco's Modified Eagle Medium (DMEM), Glutamax, 10 Vol.-% fetal bovine serum (FBS) and 1 Vol.-% Streptomycin/Penicillin solution. A screening test was performed to select the etching combinations with the lowest initial mean degradation depth. The most promising etching procedures were chosen for further long term degradation tests lasting up to 30 days in cell culture medium. The surfaces of the etched samples and for selected samples after degradation were characterized by interferometry, OM, SEM, and XRD to correlate the influence of morphology, roughness and microstructure on the degradation rate. Etching with 250 g/L HAc and 150 s leads to the most uniform degradation with low degradation rate compared to non-etched Mg-5Gd. %0 conference lecture %@ %A Gawlik, M.M., Wiese, B., Steiner, M., Lamaka, S., Dahms, M., Ebel, T., Willumeit-Roemer, R., Welle, A. %D 2017 %J 3rd EURO Intelligent Materials 2017 %T The influence of surface treatments on the degradation behaviour of Mg-5Gd %U %X %0 conference lecture %@ %A Marek, R., Wohlfender, F., Wiese, B., de Wild, M. %D 2017 %J 9th Symposium on Biodegradable Metals, Biometall 2017 %T Customizing the microstructure in three-dimensional Mg structures %U %X %0 conference object %@ %A Marek, R., Wohlfender, F., Wiese, B., de Wild, M. %D 2017 %J Abstract Book, 9th Symposium on Biodegradable Metals, Biometall 2017 %P Met-4 %T Customizing the microstructure in three-dimensional Mg structures %U %X %0 conference lecture %@ %A Moosmann, J., Zeller-Plumhoff, B., Wieland, D.C.F., Galli, S., Krueger, D., Dose, T., Burmester, H., Wilde, F., Bech, M., Peruzzi, N., Wiese, B., Hipp, A., Beckmann, F., Hammel, J., Willumeit-Roemer, R. %D 2017 %J Developments in X-Ray Tomography XI, SPIE Optics and Photonics Conference 2017 %R doi:10.1117/12.2275121 %T Biodegradable magnesium-based implants in bone studied by synchrotron radiation microtomography %U https://doi.org/10.1117/12.2275121 %X %0 conference object %@ %A Harmuth, J., Wiese, B., Bohlen, J., Ebel, T., Willumeit-Roemer, R. %D 2017 %J Abstract Book, 9th Symposium on Biodegradable Metals, Biometall 2017 %P Met-5 %T Influence of extrusion parameters on Mg-10Gd %U %X %0 conference lecture %@ %A Wolff, M., Luczak, M., Schaper, J., Wiese, B., Dahms, M., Ebel, T., Willumeit-Roemer, R., Klassen, T. %D 2017 %J 9th Symposium on Biodegradable Metals, Biometall 2017 %T Manufacturing and Assessment of high strength Mg-Nd-Gd-Zr-Zn alloy implant prototypes and test specimen, using PM (Powder Metallurgy) methods %U %X %0 conference object %@ %A Wolff, M., Luczak, M., Schaper, J., Wiese, B., Dahms, M., Ebel, T., Willumeit-Roemer, R., Klassen, T. %D 2017 %J Abstract Book, 9th Symposium on Biodegradable Metals, Biometall 2017 %P Met-8 %T Manufacturing and Assessment of high strength Mg-Nd-Gd-Zr-Zn alloy implant prototypes and test specimen, using PM (Powder Metallurgy) methods %U %X %0 conference paper %@ %A Moosmann, J., Zeller-Plumhoff, B., Wieland, D.C.F., Galli, S., Krueger, D., Dose, T., Burmester, H., Wilde, F., Bech, M., Peruzzi, N., Wiese, B., Hipp, A., Beckmann, F., Hammel, J., Willumeit-Roemer, R. %D 2017 %J Proceedings of SPIE, Developments in X-Ray Tomography XI %P 1039100 %R doi:10.1117/12.2275121 %T Biodegradable magnesium-based implants in bone studied by synchrotron radiation microtomography %U https://doi.org/10.1117/12.2275121 %X Permanent implants made of titanium or its alloys are the gold standard in many orthopedic and traumatological applications due to their good biocompatibility and mechanical properties. However, a second surgical intervention is required for this kind of implants as they have to be removed in the case of children that are still growing or on patient’s demand. Therefore, magnesium-based implants are considered for medical applications as they are degraded under physiological conditions. The major challenge is tailoring the degradation in a manner that is suitable for a biological environment and such that stabilization of the bone is provided for a controlled period. In order to understand failure mechanisms of magnesium-based implants in orthopedic applications and, further, to better understand the osseointegration, screw implants in bone are studied under mechanical load by means of a push-out device installed at the imaging beamline P05 of PETRA III at DESY. Conventional absorption contrast microtomography and phasecontrast techniques are applied in order to monitor the bone-to-implant interface under increasing load conditions. In this proof-of-concept study, first results from an in situ push-out experiment are presented. %0 conference lecture %@ %A Hort, N., Wiese, B., Dieringa, H., Kainer, K.U. %D 2016 %J High Tech Die Casting, HTDC 2016 %T Protecting molten Magnesium and its alloys %U %X %0 conference lecture %@ %A Schmid-Fetzer, R., Kozlov, A., Wiese, B., Mendis, C.L., Tolnai, D., Kainer, K.U., Hort, N. %D 2016 %J 145th Annual Meeting and Exhibition, TMS 2016 %R doi:10.1002/9781119274803.ch15 %T Thermodynamic Description of Reactions between Mg and CaO %U https://doi.org/10.1002/9781119274803.ch15 %X %0 conference lecture %@ %A Schmid-Fetzer, R., Kozlov, A., Wiese, B., Mendis, C.L., Tolnai, D., Kainer, K.U., Hort, N. %D 2016 %J Magnesium Technology 2016, TMS 2016 Supplemental Proceedings, 145th Annual Meeting and Exhibition, TMS 2016 %P 67-72 %R doi:10.1002/9781119274803.ch15 %T Thermodynamic Description of Reactions between Mg and CaO %U https://doi.org/10.1002/9781119274803.ch15 %X CaO is considered as possible replacement for cover gases such as SF6 during melting and casting of Mg alloys. Such CaO additions to molten Mg increase the ignition resistance by forming a protective oxide layer. The actual reactions between liquid Mg and CaO are not well understood. An approach based on chemical reaction equations cannot capture the "CaO dissolution" process. This work presents the development of a consistent thermodynamic description of the ternary Mg-Ca-O alloy system. To that end a revision of the thermodynamic data of key oxides, CaO and MgO, has been performed based on original experimental work so far not considered in thermodynamic databases or tabulations. The formation of a liquid Mg-Ca-[O] alloy during the reaction is predicted from the thermodynamic calculations at melting temperatures; solidification simulations are also performed. These predictions from thermodynamic simulations are validated by experimental data using in situ synchrotron radiation diffraction. %0 conference poster %@ %A Wohlfender, F., Saxer, S., Wiese, B., Rueegg, J., Dietschy, A., Schumacher, R., de Wild, M. %D 2016 %J [MEET THE EXPERT] Implants, Innovation – from Idea to Patient Benefit %T Preliminary microstructural investigation of Mg cubes produced by SLM %U %X %0 journal article %@ 0026-0843 %A Hort, N., Wiese, B., Dieringa, H., Kainer, K.U. %D 2016 %J Metallurgia Italiana %N 6 %P 105-108 %T Protecting molten Magnesium and its alloys %U 6 %X its own restrictions with maximum working space concentrations. It might be necessary to reuse again fluxes, but they also have limitations. If magnesium and its alloys shall be further used and processed in the EU, alternative ways of magnesium melt protection need to be established within the near future. This contribution will discuss available methods to protect molten Mg and their consequences. %0 conference lecture %@ %A Schmid-Fetzer, R., Kozlov, A., Wiese, B., Mendis, C., Tolnai, D., kainer, K.U., Hort, N. %D 2016 %J Materials Science and Engineering, MSE 2016 %T Thermodynamic description of reactions between Mg and CaO %U %X %0 doctoral thesis %@ %A Wiese, B. %D 2016 %J %R doi:10.21268/20170504-133828 %T The Effect of CaO on Magnesium and Magnesium Calcium Alloys (Dissertation) %U https://doi.org/10.21268/20170504-133828 %X %0 conference object %@ 1473-2262 %A Wohlfender, F., Saxer, S., Wiese, B., Rueegg, J., Dietschy, A., Schumacher, R., de Wild, M. %D 2016 %J European Cells and Materials %N S1 %P 24 %T Preliminary microstructural investigation of Mg cubes produced by SLM %U S1 %X No abstract %0 conference object %@ %A Szakacs, G., Mendis, C., Wiese, B., Stark, A., Kainer, K.U., Hort, N. %D 2015 %J Abstract Book, 7th BIOMETAL, Symposium on Biodegradable Metals for Biomedical Applications %P Met-22 %T In situ synchroton radiation diffraction during solidification of Mg4Y2Nd and Mg4Y2Ag1Nd alloys %U %X %0 journal article %@ 0925-8388 %A Wiese, B., Mendis, C.L., Tolnai, D., Stark, A., Schell, N., Reichel, H.-P., Brueckner, R., Kainer, K.U., Hort, N. %D 2015 %J Journal of Alloys and Compounds %P 64-66 %R doi:10.1016/j.jallcom.2014.08.151 %T CaO dissolution during melting and solidification of a Mg–10 wt.% CaO alloy detected with in situ synchrotron radiation diffraction %U https://doi.org/10.1016/j.jallcom.2014.08.151 %X The phase dissolution and evolution during the melting and the solidification of Mg containing 10 wt.% CaO was investigated in the temperature range of 20–680 °C. The dissolution of CaO and the formation of Mg2Ca were detected with in situ synchrotron radiation diffraction. The dissolution of CaO was observed at ∼407 °C with the detection of a peak unique to the Mg2Ca phase prior to melting of Mg. After the solidification no CaO was detected, and Mg2Ca and MgO phases were observed. %0 conference poster %@ %A Wiese, B., Tolnai, D., Mendis, C.L., Szakacs, G., Stark, A., Schell, N., Reichel, H.-P., Kainer, K.U., Hort, N. %D 2015 %J DESY Photon Science Users´ Meeting 2015 %T In situ diffraction of CaO dissolution during melting and solidification of a Mg-20CaO alloy %U %X %0 conference lecture %@ %A Wiese, B., Mendis, C.L., Ovri, H., Reichel, H.-P., Lorenz, U., Kainer, K.U., Hort, N. %D 2015 %J 10th International Conference on Magnesium Alloys and Their Applications, Mg 2015 %T Role of CaO and Cover Gases on Protecting the Cast Surface of Mg %U %X %0 journal article %@ 0255-5476 %A Hort, N., Wiese, B., Dieringa, H., Kainer, K.U. %D 2015 %J Materials Science Forum, Light Metals Technology 2015 %P 78-81 %R doi:10.4028/www.scientific.net/MSF.828-829.78 %T Magnesium Melt Protection %U https://doi.org/10.4028/www.scientific.net/MSF.828-829.78 %X there are similar discussions regarding all other fluorinated hydrocarbons. Due to this, new innovative ways have to be found or old methods have to be renewed to allow Mg industries further safe processing of molten magnesium. This contribution will report the state of the art in protecting molten Mg and alternatives to the use of SF6. %0 conference paper %@ %A Hort, N., Wiese, B., Dieringa, H., Kainer, K.U. %D 2015 %J Light Metals Technology 2015, 7th Internaternational Light Metals Technology Conference, LMT 2015 %P 78-81 %T Magnesium Melt Protection %U %X %0 conference lecture %@ %A Szakacs, G., Mendis, C., Wiese, B., Stark, A., Kainer, K.U., Hort, N. %D 2015 %J 7th BIOMETAL, Symposium on Biodegradable Metals for Biomedical Applications %T In situ synchroton radiation diffraction during solidification of Mg4Y2Nd and Mg4Y2Ag1Nd alloys %U %X %0 conference lecture %@ %A Hort, N., Wiese, B., Dieringa, H., Kainer, K.U. %D 2015 %J 7th Internaternational Light Metals Technology Conference, LMT 2015 %T Magnesium Melt Protection %U %X %0 conference object %@ 1473-2262 %A Szakacs, G., Mendis, C., Wiese, B., Stark, A., Kainer, K.U., Hort, N. %D 2015 %J European Cells and Materials %N S 3 %P 22 %T In situ synchroton radiation diffraction during solidification of Mg4Y2Nd and Mg4Y2Ag1Nd alloys %U S 3 %X No abstract %0 conference paper %@ %A Wiese, B., Mendis, C.L., Ovri, H., Reichel, H.-P., Lorenz, U., Kainer, K.U., Hort, N. %D 2015 %J Proceedings of 10th International Conference on Magnesium Alloys and Their Applications, Mg 2015 %P 814-819 %T Role of CaO and Cover Gases on Protecting the Cast Surface of Mg %U %X Previous investigations show the protective nature of CaO on Mg and commercial Mg alloys during high temperature oxidation. The addition of CaO to Mg alloys increases the health and safety at workplaces and the quality of the cast surface by increasing the oxidation resistance. However, the role the Ca or CaO on influencing the oxidation resistance is not clear. To understand the effect of Ca on the oxidation behaviour we focused on pure Mg and the investigation is conducted on Mg and Mg-CaO castings and their interaction with and without Ar-SF6 as cover gas during the casting process. The oxide layers are investigated with SEM and TEM to characterise the role of Ca and CaO. %0 conference object %@ %A Wiese, B., Mendis, C., Kainer, K.U., Hort, N. %D 2015 %J Abstract Book, 7th BIOMETAL, Symposium on Biodegradable Metals for Biomedical Applications %P Met-23 %T Can defects improve properties of metallic biomaterials %U %X %0 conference object %@ 1473-2262 %A Wiese, B., Mendis, C., Kainer, K.U., Hort, N. %D 2015 %J European Cells and Materials %N S 3 %P 23 %T Can defects improve properties of metallic biomaterials %U S 3 %X No abstract %0 conference lecture %@ %A Wiese, B., Kainer, K.U., Hort, N. %D 2015 %J Werkstoffwoche 2015 %T Koennen Legierungselemente Schutzgase in der Produktion von Magnesium ersetzen? %U %X %0 journal article %@ 0016-9781 %A Wiese, B., Hort, N., Dieringa, H., Kainer, K.U. %D 2015 %J Giesserei-Praxis : Fachzeitschrift fuer alle Bereiche der Giessereitechnik %N 12 %P 601-603 %T Schutz von Magnesiumschmelzen %U 12 %X Im schmelzflüssigen Zustand zeigt Magnesium eine hohe Affinität zu Sauerstoff. Sobald der Sauerstoffgehalt in der Atmosphäre 4 % übersteigt, wird Mg daher entflammen! Damit ergibt sich die Notwendigkeit, Mg-Schmelzen zu schützen. Zurzeit wird standardmäßig SF6 während der Primärproduktion und beim Verarbeiten von Mg-Schmelzen eingesetzt. Bedauerlicherweise ist SF6 jedoch ein Treibhausgas, das ungefähr 23.000 mal wirksamer ist, als CO2. Damit muss SF6 auch bei der Lebensdaueranalyse z.B. von Fahrzeugen berücksichtigt werden. Andere Schutzgase wie zum Beispiel SO2 oder fluorierte Kohlenwasserstoffe wie HFC134a, Novec 612, oder AMCover (= HFC134a) sind bereits als Schutzgase in der Diskussion. Zusätzlich gibt es noch eine Reihe von Schmelzsalzen, die ebenfalls in der Lage sind, Mg-Schmelzen effektiv zu schützen. Allerdings haben Schmelzsalze auch einige Nachteile und fluorierte Gase sind in der EU zusätzlich in der Diskussion. Die aktuellen Regelungen in Europa sehen zudem vor, dass SF6 ab 2018 nicht mehr oder nur sehr beschränkt eingesetzt werden darf. Eine ähnliche Diskussion wird auch für andere fluorierte Gase geführt. Daher ist es notwendig, bekannte Maßnahmen zum Schutz von Mg-Schmelzen neu zu bewerten oder neue Methoden zu entwickeln. %0 conference lecture %@ %A Wiese, B., Mendis, C., Kainer, K.U., Hort, N. %D 2015 %J 7th BIOMETAL, Symposium on Biodegradable Metals for Biomedical Applications %T Can defects improve properties of metallic biomaterials %U %X %0 conference lecture %@ %A Wiese, B., Mendis, C.L., Tolnai, D., Szakacs, G., Stark, A., Schell, N., Reichel, H.-P., Brueckner, R., Hort, N., Kainer, K.U. %D 2014 %J 143rd Annual Meeting & Exhibition, TMS 2014 %T In Situ Synchrotron Radiation Diffraction during Melting and Solidification of Mg-Al Alloys Containing CaO %U %X %0 conference paper %@ %A Wiese, B., Mendis, C.L., Tolnai, D., Szakacs, G., Stark, A., Schell, N., Reichel, H.-P., Brueckner, R., Hort, N., Kainer, K.U. %D 2014 %J Magnesium Technology 2014, Proceedings of 143rd Annual Meeting & Exhibition, TMS 2014 %P 191-195 %R doi:10.1002/9781118888179.ch38 %T In Situ Synchrotron Radiation Diffraction during Melting and Solidification of Mg-Al Alloys Containing CaO %U https://doi.org/10.1002/9781118888179.ch38 %X %0 conference lecture %@ %A Szakacs, G., Mendis, C.L., Wiese, B., Tolnai, D., Stark, A., Schell, N., Kainer, K.U., Hort, N. %D 2014 %J 6th Symposium on Biodegradable Metals %T In situ synchrotron radiation diffraction during solidification of Mg15Gd %U %X %0 conference object %@ 1473-2262 %A Szakacs, G., Mendis, C.L., Wiese, B., Tolnai, D., Stark, A., Schell, N., Kainer, K.U., Hort, N. %D 2014 %J European Cells and Materials %N S3 %P 3 %T In situ synchrotron radiation diffraction during solidification of Mg15Gd %U S3 %X No abstract %0 conference lecture %@ %A Hort, N., Wiese, B., Wolff, M., Ebel, T., Maier, P. %D 2014 %J 6th Symposium on Biodegradable Metals %T Stiffness of metals, alloys and components %U %X %0 conference object %@ 1473-2262 %A Hort, N., Wiese, B., Wolff, M., Ebel, T., Maier, P. %D 2014 %J European Cells and Materials %N S3 %P 1 %T Stiffness of metals, alloys and components %U S3 %X No abstract %0 conference lecture %@ %A Szakacs, G., Wiese, B., Mendis, C.L., Tolnai, D., Stark, A., Schell, N., Nair, M., Kainer, K.U., Hort, N. %D 2014 %J 143rd Annual Meeting & Exhibition, TMS 2014 %T In situ synchrotron radiation diffraction during solidification of Mg4Y and Mg4YxGd alloys (x - 1, 4 wt.%) %U %X %0 conference paper %@ %A Szakacs, G., Wiese, B., Mendis, C.L., Tolnai, D., Stark, A., Schell, N., Nair, M., Kainer, K.U., Hort, N. %D 2014 %J Magnesium Technology 2014, Proceedings of 143rd Annual Meeting & Exhibition, TMS 2014 %P 213-218 %R doi:10.1002/9781118888179.ch42 %T In situ synchrotron radiation diffraction during solidification of Mg4Y and Mg4YxGd alloys (x - 1, 4 wt.%) %U https://doi.org/10.1002/9781118888179.ch42 %X %0 conference poster %@ %A Wiese, B., Mendis, C., Tolnai, D., Stark, A., Schell, N., Hort, N., Kainer, K.U., Reichel, H.-P., Brueckner, R. %D 2013 %J European XFEL / DESY Photon Science Users Meeting %T In situ solidification of a Mg-10 wt% CaO %U %X %0 report part %@ %A Wiese, B., Tolnai, D., Mendis, C., Eckerlebe, H., Hort, N. %D 2013 %J Annual Report Photon Science 2013 %T In situ diffraction of the melting and the solidification of magnesium alloys containing CaO %U %X %0 conference lecture %@ %A Wiese, B., Mendis, C., Tolnai, D., Szakacs, G., Stark, A., Schell, N., Reichel, H.-P., Brueckner, R., Hort, N., Kainer, K.U. %D 2013 %J International Congress and Exhibition on Light Materials Aluminium, Magnesium, Titanium and their Alloys, Euro LightMAT 2013 %T In situ synchrotron diffraction of the solidification of Mg-Al alloys containing CaO %U %X %0 journal article %@ 0167-577X %A Tolnai, D., Mendis, C.L., Stark, A., Szakacs, G., Wiese, B., Kainer, K.U., Hort, N. %D 2013 %J Materials Letters %P 62-64 %R doi:10.1016/j.matlet.2013.03.110 %T In situ synchrotron diffraction of the solidification of Mg4Y3Nd %U https://doi.org/10.1016/j.matlet.2013.03.110 %X In situ synchrotron diffraction experiments were performed during the solidification of a Mg4Y3Nd alloy. The material was melted and solidified inside a sealed stainless steel crucible in the chamber of a Bähr 805 A/D dilatometer. The sample was heated up to 680 °C and kept at this temperature for 5 min to ensure it is molten. Afterwards it was cooled down to the fully solidified state with a cooling rate of 10 K/min. During the T(t) program diffraction patterns were acquired continuously in every 25 s (∼5 K). The forming phases were identified as α-Mg at 625 °C, Mg12Nd and Mg14Y4Nd at 545 °C, and Mg24Y5 at 320 °C. The experimental results were correlated with simulations based on thermodynamic databases. %0 conference paper %@ %A Tolnai, D., Mendis, C.L., Stark, A., Szakacs, G., Wiese, B., Kainer, K.U., Hort, N. %D 2013 %J Magnesium Technology 2013, Proceedings of TMS 2013 Annual Meeting & Exhibition %P 253-257 %R doi:10.1002/9781118663004.ch42 %T In situ synchrotron diffraction of the solidification of Mg-RE alloys %U https://doi.org/10.1002/9781118663004.ch42 %X %0 conference lecture %@ %A Tolnai, D., Mendis, C.L., Stark, A., Szakacs, G., Wiese, B., Kainer, K.U., Hort, N. %D 2013 %J 142nd Annual Meeting & Exhibition, TMS 2013 %T In situ synchrotron diffraction of the solidification of Mg-RE alloys %U %X %0 conference paper %@ %A Wiese, B., Mendis, C.L., Blawert, C., Hort, N., Kainer, K.U., Nyberg, E. %D 2013 %J Magnesium Technology 2013, Proceedings of TMS 2013 Annual Meeting & Exhibition %P 231-235 %R doi:10.1002/9781118663004.ch38 %T A new magnesium alloy system: TEXAS %U https://doi.org/10.1002/9781118663004.ch38 %X %0 conference lecture %@ %A Wiese, B., Mendis, C.L., Blawert, C., Hort, N., Kainer, K.U., Nyberg, E. %D 2013 %J 142nd Annual Meeting & Exhibition, TMS 2013 %T A new magnesium alloy system: TEXAS %U %X %0 report part %@ %A Wiese, B., Tolnai, D., Mendis, C., Stark, A., Kainer, K.U., Hort, N. %D 2012 %J Annual Report Photon Science 2012 %T In situ solidifcation of a Mg-10 wt% CaO %U %X %0 conference lecture %@ %A Ebel, T., Wolff, M., Wiese, B., Deussing, J. %D 2012 %J 25. MIM Expertenkreis Sitzung %T MIM von Magnesium %U %X %0 conference paper %@ %A Wolff, M., Wiese, B., Dahms, M., Ebel, T. %D 2011 %J Proceedings of EURO PM 2011, International Congress and Exhibition %P 271-276 %T Binder development for Magnesium Powder Injection Moulding %U %X %0 conference lecture %@ %A Wolff, M., Wiese, B., Dahms, M., Ebel, T. %D 2011 %J International Congress and Exhibition, EURO PM 2011 %T Binder development for Magnesium Powder Injection Moulding %U %X %0 conference paper %@ %A Wolff, M., Fischer, J., Wiese, B., Guelck, T., Willumeit, R., Ebel, T. %D 2010 %J Powder Metallurgy, PM 2010, Conference Proceedings, World Congress & Exhibition %P 755-764 %T Sintering of porous components from ternary Mg-Y-Ca alloys for orthopedic applications %U %X %0 conference lecture %@ %A Wolff, M., Fischer, J., Wiese, B., Guelck, T., Willumeit, R., Ebel, T. %D 2010 %J Powder Metallurgy, World Congress and Exhibition PM 2010 %T Sintering of porous components from ternary Mg-Y-Ca alloys for orthopedic applications %U