TY - GEN A1 - Eisentraut, Mark A1 - Bolz, Sebastian A1 - Sizova, Irina A1 - Bambach, Markus A1 - Weiß, Sabine T1 - Development of a heat treatment strategy for the γ-TiAl based alloy TNM-B1 to increase the hot workability T2 - SN Applied Sciences Y1 - 2019 U6 - https://doi.org/10.1007/s42452-019-1563-4 SN - 2523-3963 SN - 2523-3971 VL - 1 IS - 11 ER - TY - GEN A1 - Stendal, Johan Andreas A1 - Eisentraut, Mark A1 - Sizova, Irina A1 - Bolz, Sebastian A1 - Bambach, Markus A1 - Weiß, Sabine T1 - Effect of heat treatment on the workability of hot isostatically pressed TNM-B1 T2 - AIP Conference Proceedings Y1 - 2019 SN - 978-0-7354-1847-9 U6 - https://doi.org/10.1063/1.5112544 VL - 2113 IS - 1 ER - TY - CHAP A1 - Fellah, Mamoun A1 - Hezil, Naouel A1 - Abderrahim, Karima A1 - Samad, Mohammed Abdul A1 - Montagne, Alex A1 - Mejias, Alberto A1 - Iost, Alain A1 - Kossman, Stephania A1 - Chekalkin, Timofey A1 - Obrosov, Aleksei A1 - Weiß, Sabine T1 - Investigating the Effect of Sintering Temperature on Structural and Tribological Properties of a Nanostructured Ti–20Nb–13Zr Alloy for Biomedical Applications T2 - Characterization of Minerals, Metals, and Materials N2 - β-type Ti–20Nb–13Zr alloys with low Young’s modulus were prepared at different sintering temperatures (950, 1050, 1150, and 1250 °C). The morphological and structural characteristics of as-prepared samples were investigated by several methods. Wear tests were conducted using a ball-on-plate type oscillating tribometer under different applied loads (2, 10, and 20 N). The morphological characterization indicated that the mean pore and crystallite size continuously decreased with increasing sintering temperature to reach lowest values of 40 nm and 38 nm at 1250 °C, respectively. The relative density of the 1250 °C sintered sample was as high as 98.7%. Moreover, the higher sintering temperature resulted in higher relative density and closed porosity of the sample. Both the friction coefficient and wear rate were lower in the sample sintered at 1250 °C as compared to other samples. This enhancement in tribological properties was attributed to a closed porosity. KW - Ti-20Nb-13Zr KW - Nanobiomaterials KW - Tribological behaviour KW - Nanotribology KW - Sintering KW - Biomedical applications Y1 - 2020 SN - 978-3-030-36628-5 SN - 978-3-030-36627-8 U6 - https://doi.org/10.1007/978-3-030-36628-5_61 SN - 2367-1181 SN - 2367-1696 SP - 619 EP - 629 PB - Springer CY - Cham ER - TY - GEN A1 - Fellah, Mamoun A1 - Hezil, Naouel A1 - Touhami, Mohamed Zine A1 - Hussien, Mohammed A. A1 - Montagne, Alex A1 - Mejias, Alberto A1 - Iost, Alain A1 - Kossman, Stephania A1 - Chekalkin, Timofey A1 - Obrosov, Aleksei A1 - Weiß, Sabine T1 - Effect of Sintering Temperature on Mechanical and Tribological Behavior of Ti–Ni Alloy for Biomedical Applications T2 - TMS 2020 149th Annual Meeting & Exhibition Supplemental Proceedings N2 - Ti–Ni powder compacts were prepared by mechanical alloying (MA), followed by hot isostatic pressing (HIP). Afterwards, the samples were sintered at different temperatures (950, 1050, 1150 and 1250 °C). Microhardness, density, crystallite size as well as microstrain of the sintered samples were measured and analyzed. Wear characteristics in phosphate-buffered saline (PBS) solution was tested under different applied loads of 2 N, 10 N, and 20 N, respectively. The results indicated that the crystallite size continuously decreases with increasing sintering temperature and reaches the lowest value of 31.3 nm at 1250 °C. The relative density of the sample sintered at 1250 °C is 98.0%. Moreover, the higher sintering temperatures lead to the higher relative density and the increase in hardness and young’s modulus of the sample. At the same time the friction coefficient and wear rate were lower for the samples sintered at 1250 °C. This improvement in friction and wear resistance is attributed to the grain size refinement. Ti–Ni sintered at 1250 °C showed good tribological performance under all test conditions. KW - Ti–Ni KW - Nanobiomaterials KW - Tribological behaviour KW - Sintering KW - Biomedical applications Y1 - 2020 SN - 978-3-030-36295-9 SN - 978-3-030-36296-6 U6 - https://doi.org/10.1007/978-3-030-36296-6_157 SN - 2367-1181 SN - 2367-1696 SP - 1701 EP - 1710 PB - Springer CY - Cham ER - TY - GEN A1 - Hezil, Naouel A1 - Fellah, Mamoun A1 - Montagne, Alex A1 - Iost, Alain A1 - Obrosov, Aleksei A1 - Weiß, Sabine T1 - Removal of Chromium (VI) from Water onto Activated Carbon by Adsorption in Dynamic Mode T2 - TMS 2020 149th Annual Meeting & Exhibition Supplemental Proceedings N2 - Hexavalent chromium pollution from industrial waste water is a serious problem as it can cause adverse effects on the environment. Several methods are used to reduce the harmful effects of this pollutant, especially physico-chemical methods, such as adsorption technology. The present study aims to remove Cr (VI) from industrial sources in a fixed-bed column of activated carbon. The experiments were carried out at natural pH and temperature with a flow rate (5, 10, and 20 mL/min) and bed height (3.5 cm). Breakthrough curves for feed concentrations (0.01, 0.03, and 0.05 mol/L) were investigated. The results indicated a marked decrease up to 99%. The value of the flow constant for the Thomas model decreased with the increase in the concentration of the incoming substance, but increased with the increase in the flow rate. KW - Hexavalent chromium KW - Activated carbon KW - Adsorption KW - Breakthrough curve KW - Fixed-bed column Y1 - 2020 SN - 978-3-030-36295-9 SN - 978-3-030-36296-6 U6 - https://doi.org/https://doi.org/10.1007/978-3-030-36296-6_80 SN - 2367-1181 SN - 2367-1696 SP - 855 EP - 863 PB - Springer CY - Cham ER - TY - GEN A1 - Evdokimov, Anton A1 - Doynov, Nikolay A1 - Ossenbrink, Ralf A1 - Obrosov, Aleksei A1 - Weiß, Sabine A1 - Michailov, Vesselin T1 - Thermomechanical laser welding simulation of dissimilar steel-aluminum overlap joints T2 - International Journal of Mechanical Sciences N2 - Mixing of steel and aluminum within the weld pool during keyhole laser welding results in a complex dissimilar microstructure, which in turn, initiates a shift in weld metal mechanical properties. In this study, a numerical model for computation of distortions in laser-welded dissimilar overlap joints (austenitic stainless steel 304 – 6082-T6 aluminum alloy), which considers properties of the mixed steel-aluminum weld metal was developed. The required yield strength, Young's modulus, and strain hardening exponent of the weld metal were experimentally determined using the indentation technique coupled with energy-dispersive X-ray spectroscopy. The designed material model calculates the weld elastic-plastic properties as a function of the aluminum concentration. The softening of the alloys in the heat-affected zone was determined by physical simulations and considered as a function of maximum temperature. Computed and measured distortions showed good agreement for various welding regimes with an average deviation of 18.4%. The sensitivity analyses indicated that the application of the developed weld material model significantly improves the accuracy of the thermomechanical simulations. Y1 - 2021 U6 - https://doi.org/10.1016/j.ijmecsci.2020.106019 SN - 1879-2162 VL - 190 ER - TY - GEN A1 - Baigonakova, Gulsharat A1 - Marchenko, Ekaterina A1 - Chekalkin, Timofey A1 - Kang, Ji-hoon A1 - Weiß, Sabine A1 - Obrosov, Aleksei T1 - Influence of Silver Addition on Structure, Martensite Transformations and Mechanical Properties of TiNi–Ag Alloy Wires for Biomedical Application T2 - Materials N2 - The microstructural and functional behavior of TiNi-based wires with a silver content of 0–1.5 at.% was evaluated. The concentration range for Ag doping determined for the TiNi wires with potential for the medical industry was 0–0.2 at.%. Microstructure analysis of TiNi wires with different silver contents at room temperature indicated a multiphase structural state. Various internal structures with tangled grain boundaries were formed by intense plastic deformation. The nanocrystalline structure and phase state of wire with the minimum silver content (0.1 at.% Ag) provide full shape recovery, the greatest reversible strain, and optimal strength and ductility. TiNi ingots with a high Ag content (0.5–1.5 at.%) cracked under minimum load due to excess silver that crystallized along the grain boundaries and broke cohesion bonds between the TiNi grains. KW - shape memory alloy KW - silver KW - doping KW - mechanical properties KW - nanostructured material KW - wire Y1 - 2020 UR - https://www.mdpi.com/1996-1944/13/21/4721 U6 - https://doi.org/10.3390/ma13214721 SN - 1996-1944 VL - 13 IS - 21 ER - TY - GEN A1 - Hazil, Naouel A1 - Fellah, Mamoun A1 - Montagne, Alex A1 - Iost, Alain A1 - Obrosov, Aleksei A1 - Weiß, Sabine T1 - Study of the photocatalytic degradation of Orange methyl dye in the presence of titanium dioxide T2 - La Troisième Conférence Méditerranéenne de la Biodiversité 2019 (BIODIV 2019) N2 - The use of photocatalytic techniques for water purification and wastewater treatment is very widespread, in our work we used TiO2 to photocatalyrate orange methyl (MO). In addition, the effects of some parameters on photodegradation of MO have been studied, such as the presence and / or absence of light (UV). The use of TiO2 showed a high MO degradation efficiency of up to 98%. The presence of H2O2 in the photocatalytic reaction may favor the photocatalytic degradation efficiencies. In addition, the experimental results have demonstrated an excellent rate of the order of 99%. KW - Titanium Dioxide KW - Photocatalytic Degradation Y1 - 2019 UR - http://ascob.net/files/abstract_book_biodiv2019_finale.pdf SP - 105 PB - L’ASCOB-SYRTIS CY - Hammamet, Tunisie ER - TY - GEN A1 - Prechavut, Ananya A1 - Weiß, Sabine T1 - Analyse der Korrosionsprodukte eines im CO2 Methanisierungsprozess verwendeten Edelstahlflansches aus 316L N2 - Die Weltklimakonferenz fordert eine massive Senkung der Treibhausgasemissionen mittels Abkehr von der Nutzung fossiler Brennstoffe hin zur Verwendung umweltverträglich hergestellter Energie. Da erneuerbare Energien aber bisher nicht durchweg bedarfsgerecht zur Verfügung stehen und schlecht speicherbar sind, besteht eine kurzfristige Lösungsmöglichkeit in Umwandlung, Speicherung und Wiederverwendung klimaschädlicher Verbrennungsgase. Eine effiziente Lösung zur Nutzung von CO2 ist dessen Umwandlung in ein speicherbares, zur Energieerzeugung nutzbares Gas. Mit der Methanisierung von CO2 kann eine erhebliche Reduzierung der Treibhausgasemissionen erreicht werden, wenn Methanschlupf vermieden wird. Bei dieser sogenannten Sabatier-Reaktion, die normalerweise bei 350°C bis 600°C stattfindet, reagiert Kohlendioxid mit Wasserstoff zu Methan. Als Reaktionsprodukte treten außer Methan und Wasser die Rest-Reaktanten sowie kleine Mengen an Verunreinigungen aus dem Verbrennungsprozess auf. Reaktionsbehälter und Leitungen bestehen üblicherweise aus Edelstahl. Durch hohe Umgebungs-temperatur und aggressive Umgebungsmedien kann auch bei dem normalerweise temperatur- und korrosionsbeständigen Werkstoff 316L Korrosion auftreten, Materialeigenschaften beeinflussen und zu Materialversagen führen. Zur Bewertung des Einflusses des CO2 Methanisierungs-Prozesses auf 316L wurde ein Methanisierungs-Reaktor im Labormaßstab nach der Nutzung demontiert und untersucht. In verschiedenen Bauteilen des Reaktors (Gaszuleitung, Gasaustritt, Reaktorsegment) wurden Korrosionsbeläge gefunden. Abhängig von ihrer Lage im Bauteil sind diese Korrosionsschichten sehr unterschiedlich aufgebaut. Mikrostruktur und Elementzusammensetzung der Schichten wurden mittels Rasterelektronenmikroskopie kombiniert mit energiedispersiver Röntgenspektroskopie analysiert. Während die Gaszuleitung nur moderaten Korrosionsangriff zeigt konnten im Bereich des Gasaustritts Spalt-, Kontakt- und Lochkorrosion nachgewiesen werden. Innerhalb der Korrosions¬schichten wurden drei Zonen (Mehrschichtenstruktur, Partikelansammlung und brüchiger Passivfilm) identifiziert. Die Mehrschichtzone setzt sich aus kolumnaren und granularen Strukturen zusammen, die Partikelansammlungen bestehen aus zylinderförmigen und kugelförmigen Partikeln. Die Elementzusammensetzung innerhalb der Korrosionsschichten lässt auf Kontaktkorrosion verursacht durch das Material der Dichtringe schließen. Y1 - 2020 UR - https://met2020.dgm.de/programm/?tx_dgmprogram_fullprogram%5Bsession%5D=9241&tx_dgmprogram_fullprogram%5Baction%5D=show&tx_dgmprogram_fullprogram%5Bcontroller%5D=Session&cHash=2c39b0ff319036dcd452cdf3debd6573 ER - TY - GEN A1 - Prechavut, Ananya A1 - Weiß, Sabine T1 - Corrosion Analysis of a 316L Stainless Steel Gas Outlet Sealed with a Copper Ring Used in the CO2 Methanation Process N2 - The central commitment of the 2015 World Climate Conference is to limit geothermal heating by massively reducing greenhouse gas emissions by decreasing the use of fossil fuels and promoting environmentally friendly energy. However, since renewable energies have so far not been available as required and are difficult to store, there is a short-term solution in the conversion, storage and reuse of climate-damaging combustion gases. An efficient solution for using CO2 is to convert it into a gas that can be stored and used to generate energy. With the so-called “power-to-gas technology”, a significant reduction in greenhouse gas emissions can be achieved by methanation of CO2 if methane slip is avoided. Methanation is a chemical reaction in which carbon dioxide reacts with hydrogen to methane. This transformation, which normally takes place at 350 ° C to 600 ° C, is also known as the Sabatier reaction. In addition to methane and water, the remaining reactants such as carbon dioxide, hydrogen, oxygen and nitrogen as well as small amounts of impurities from the combustion process, occur as reaction products. Reaction containers and lines are usually made of stainless steel. Due to high ambient temperature and aggressive ambient media, corrosion can also occur with the generally temperature and corrosion-resistant 316L material, influence material properties and lead to material failure. To assess the influence of the CO2 methanation process on 316L, a laboratory-scale methanation reactor was fractioned and examined after use. Corrosion deposits were found in various components of the reactor (gas supply line, gas outlet, reactor segment). Depending on their position within the component, these corrosion layers are structured very differently. Microstructure and element composition of the layers were analyzed using scanning electron microscopy combined with energy-dispersive X-ray spectroscopy. While the gas supply shows only moderate corrosion attack, crevice, contact- and pitting corrosion were detected in the corroded area of the gas outlet. Three zones (multilayer structure, particle accumulation and brittle passive film) were identified within the corrosion layers. The multi-layer zone is composed of columnar and granular structures, the particle accumulations consist of cylindrical and spherical particles. The element composition within the corrosion layers suggests contact corrosion caused by the material of the sealing rings. Y1 - 2020 UR - https://www.mse-congress.de/program/poster-session/?tx_dgmprogram_fullprogram%5Bsession%5D=9384&tx_dgmprogram_fullprogram%5Baction%5D=show&tx_dgmprogram_fullprogram%5Bcontroller%5D=Session&cHash=5069393772f53823bac5d5cde190c414 ER -