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 - TY - GEN A1 - Eisentraut, Mark A1 - Stendal, Johan Andreas A1 - Bolz, Sebastian A1 - Bambach, Markus A1 - Weiß, Sabine T1 - Applying a softening adapted acceleration to the hot deformation of TNM-B1 T2 - MRS Fall Meeting 2020 N2 - Hot isostatically forged TiAl turbine blades made of TNM-B1 are commercially used in aircraft engines, as they offer significantly lower weight than the traditional nickel-based blades while exhibiting similar strength. Like other TiAl alloys, TNM-B1 displays high peak stress followed by a strong softening behavior (i.e. stress reduction) during hot deformation. This softening can be used to accelerate the deformation process by reducing the processing time and in turn the costs for TNM-B1 parts. In order to avoid increased damage during the accelerated process, a pre-heat treatment (HT) for the hot isostatically pressed material (HIP) is required. To simulate the accelerated forming process, hot compression tests were performed with a DIL805A/D/T dilatometer from TA Instruments (New Castle, Delaware, USA) with different strain rates (0.0013, 0.005, 0.01 and 0.05) and temperatures (T=1150, 1175 and 1200°C). Deformation of the heat-treated state revealed lower flow stress (in both, peak stresses and steady state stresses) and fewer voids compared to the HIP state (Fig. 1.a). The compression test data were used to develop material and temperature specific strain rate profiles based on a material model. Subsequently, hot compression tests were performed with different strain rate profiles (starting strain rates 0.0013 and 0.0052) for the HIP and the HT state. The results were evaluated with regard to their microstructure, deformation, and damage behavior. A reduction of the processing time for all tested strain rates profiles by factors 2-3 could be achieved compared to constant strain rates. Furthermore, the results indicated that the deformation with strain rate profiles (compared to constant strain rates) did not significantly change the resulting microstructure or damage tolerance of the HT state. Y1 - 2020 UR - https://www.mrs.org/meetings-events/fall-meetings-exhibits/2020-mrs-spring-and-fall-meeting/call-for-papers/symposium-sessions-detail?code=F.SF07 ER - TY - GEN A1 - Morozova, Iuliia A1 - Obrosov, Aleksei A1 - Naumov, Anton A1 - Królicka, Aleksandra A1 - Golubev, Iurii A1 - Bokov, Dmitry O. A1 - Doynov, Nikolay A1 - Weiß, Sabine A1 - Michailov, Vesselin T1 - Impact of Impulses on Microstructural Evolution and Mechanical Performance of Al-Mg-Si Alloy Joined by Impulse Friction Stir Welding T2 - Materials N2 - Impulse Friction Stir Welding (IFSW) was utilized to join 6082–T6 alloy plates at various impulse frequencies. A distinctive feature of IFSW is the generation of mechanical impulses that enhances the forging action of the tool, and thereby, alters the weld microstructure. The microstructural evolution in the Stir Zone (SZ) with special focus on the strengthening precipitation behavior, and overall mechanical properties of the IFSW joints have been investigated. It was demonstrated that the strengthening β″ precipitates reprecipitated in the SZ of the IFSW joints during natural aging. In contrast, no precipitates were found in the SZ of the Friction Stir Welding (FSW) weld. Partial reversion of β″ after IFSW is supposed to occur due to more developed subgrain network and higher dislocation density introduced by impulses that accelerated precipitation kinetics. Dynamic recrystallisation was facilitated by impulses resulting in a fine, homogeneous structure. There was no significant difference between the microhardness in the SZ, tensile and yield strength of the FSW and IFSW joints. However, the application of impulses demonstrated the smoothing of the hardness reduction in the transition region at the advancing side. The shift of the fracture location from the Heat-Affected Zone (HAZ) by FSW to the SZ as well as higher elongation of the joints by IFSW of lower frequencies could be related to the grain refinement and the change of the grain orientation. KW - Al-Mg-Si alloy KW - impulse friction stir welding (IFSW) KW - precipitation KW - microstructure evolution KW - mechanical properties Y1 - 2021 UR - https://www.mdpi.com/1996-1944/14/2/347/htm U6 - https://doi.org/https://doi.org/10.3390/ma14020347 SN - 1996-1944 VL - 14 IS - 2 ER - TY - GEN A1 - Biedunkiewicz, Anna A1 - Figiel, Paweł A1 - Garbiec, Dariusz A1 - Obrosov, Aleksei A1 - Pawlyta, Mirosława A1 - Biedunkiewicz, Witold A1 - Pruss, Przemysław A1 - Rokosz, Krzysztof A1 - Wróbel, Rafał A1 - Raaen, Steinar A1 - Weiß, Sabine A1 - Bokov, Dmitry O. T1 - Influence of Elemental Carbon (EC) Coating Covering nc-(Ti,Mo)C Particles on the Microstructure and Properties of Titanium Matrix Composites Prepared by Reactive Spark Plasma Sintering T2 - Materials N2 - This paper describes the microstructure and properties of titanium-based composites obtained as a result of a reactive spark plasma sintering of a mixture of titanium and nanostructured (Ti,Mo)C-type carbide in a carbon shell. Composites with different ceramic addition mass percentage (10 and 20 wt %) were produced. Effect of content of elemental carbon covering nc-(Ti,Mo)C reinforcing phase particles on the microstructure, mechanical, tribological, and corrosion properties of the titanium-based composites was investigated. The microstructural evolution, mechanical properties, and tribological behavior of the Ti + (Ti,Mo)C/C composites were evaluated using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), electron backscatter diffraction analysis (EBSD), X-ray photoelectron spectroscopy (XPS), 3D confocal laser scanning microscopy, nanoindentation, and ball-on-disk wear test. Moreover, corrosion resistance in a 3.5 wt % NaCl solution at RT were also investigated. It was found that the carbon content affected the tested properties. With the increase of carbon content from ca. 3 to 40 wt % in the (Ti,Mo)C/C reinforcing phase, an increase in the Young’s modulus, hardness, and fracture toughness of spark plasma sintered composites was observed. The results of abrasive and corrosive resistance tests were presented and compared with experimental data obtained for cp-Ti and Ti-6Al-4V alloy without the reinforcing phase. Moreover, it was found that an increase in the percentage of carbon increased the resistance to abrasive wear and to electrochemical corrosion of composites, measured by the relatively lower values of the friction coefficient and volume of wear and higher values of resistance polarization. This resistance results from the fact that a stable of TiO2 layer doped with MoO3 is formed on the surface of the composites. The results of experimental studies on the composites were compared with those obtained for cp-Ti and Ti-6Al-4V alloy without the reinforcing phase. KW - nanocomposites KW - TiMMCs KW - spark plasma sintering KW - (Ti,Mo)C/C KW - EBSD KW - fracture toughness Y1 - 2021 UR - https://www.mdpi.com/1996-1944/14/1/231 U6 - https://doi.org/https://doi.org/10.3390/ma14010231 SN - 1996-1944 VL - 14 IS - 1 ER - TY - GEN A1 - Stendal, Johan Andreas A1 - Eisentraut, Mark A1 - Sizova, Irina A1 - Bolz, Sebastian A1 - Weiß, Sabine A1 - Bambach, Markus T1 - Accelerated hot deformation and heat treatment of the TiAl alloy TNM-B1 for enhanced hot workability and controlled damage T2 - Journal of Materials Processing Technology Y1 - 2021 U6 - https://doi.org/10.1016/j.jmatprotec.2020.116999 SN - 0924-0136 VL - Vol. 291 ER - TY - GEN A1 - Fouzia, Hammadi A1 - Fellah, Mamoun A1 - Hezil, Naouel A1 - Aissani, Linda A1 - Mimanne, Goussem A1 - Mechachti, Said A1 - Samad, Mohammed Abdul A1 - Montagne, Alex A1 - Iost, Alain A1 - Weiß, Sabine A1 - Obrosov, Aleksei T1 - The effect of milling time on the microstructure and mechanical properties of Ti-6Al-4Fe alloys T2 - Materials Today Communications N2 - Replacement of toxic and expensive vanadium (V) in medical grade titanium alloys with cheaper and non-toxic elements such as iron (Fe) or niobium (Nb), is an important step forward in developing safer and less expensive biomaterials. Evaluating the effect of different process parameters such as the milling time on the properties of these newly developed alloys helps in understanding and controlling their behavior. Hence, in this study, the influence of ball-milling duration (2, 6, 8, 12 and 18 h) on crystalline structure, phase evolution, densification, and mechanical characteristics of biomedical nanocrystalline Ti-6Al-4Fe (wt. %) alloys is investigated. X-ray diffraction (XRD) confirmed that after 6 h of milling, aluminum (Al) and Fe completely dissolved into Ti matrix to form a solid solution of Ti (Al, Fe). XRD further revealed that the crystallite size decreased from 56 to 30 nm and the micro-strain increased with an increase in milling time. A decrease in porosity along with an increase in density is also observed for the alloys with increasing milling time. Moreover, the values of porosity obtained for the developed Ti-6Al-4Fe alloys ranged from 1 to 12 %, which is comparable to the porosity of one of the cortical bones making it a potential candidate for bone replacements. Microhardness measurements showed that the hardness of the Ti-6Al-4Fe alloys was greater than the hardness of the conventional Ti-6Al-4V alloys. It was observed that the Ti-6Al-4Fe alloy fabricated with the powders milled for 2 h showed the lowest value of Young’s Modulus. Milling time also had a significant effect on the surface roughness of the alloy samples, which showed a decreasing trend with increasing milling times. KW - Ti-based alloys KW - Microstructure KW - Mechanical properties KW - Ball-milling KW - Biomaterials KW - Milling time Y1 - 2021 UR - https://www.sciencedirect.com/science/article/abs/pii/S2352492821004207#! U6 - https://doi.org/10.1016/j.mtcomm.2021.102428 SN - 2352-4928 VL - 27 ER - TY - GEN A1 - Grudinin, V. A. A1 - Sidelev, D. V. A1 - Bleykher, G. A. A1 - Yuriev, Yu N. A1 - Krivobokov, V. P. A1 - Berlin, E. V. A1 - Grigoriev, V. Yu A1 - Obrosov, Aleksei A1 - Weiß, Sabine T1 - Hot target magnetron sputtering enhanced by RF-ICP source for CrNx coatings deposition T2 - Vacuum N2 - This article describes hot Cr target magnetron sputtering enhanced by a radio-frequency inductively coupled plasma (RF-ICP) source in an Ar + N2 atmosphere. Optical emission spectroscopy revealed an opportunity to perform magnetron sputtering in an inert (Ar) atmosphere, while the CrNx coating can be deposited on a substrate in a chemically reactive atmosphere formed by the RF-ICP source. High stability and repeatability of deposition process were observed, and the deposition rate of the CrNx coatings increased from 106 to 127 nm/min as N2 flow rate rose. The power of the RF-ICP source and the N2 flow rate can be used to tailor and control deposition conditions. The XRD and WDS measurements showed the effect of deposition conditions on the crystal structure and elemental composition of CrNx coatings. It was found that the change of substrate bias, RF-ICP source power and N2 flow rate result in variation of coating stoichiometry from pure Cr to CrN. KW - CrN coatings KW - Hot target KW - Magnetron sputtering KW - High-rate deposition KW - RF inductively Coupled plasma Y1 - 2021 UR - https://www.sciencedirect.com/science/article/pii/S0042207X21003523?via%3Dihub#! U6 - https://doi.org/10.1016/j.vacuum.2021.110400 SN - 0042-207X VL - 191 ER - TY - GEN A1 - Krzywiński, Kamil A1 - Sadowski, Łukasz A1 - Stefaniuk, Damian A1 - Obrosov, Aleksei A1 - Weiß, Sabine T1 - Engineering and Manufacturing Technology of Green Epoxy Resin Coatings Modified with Recycled Fine Aggregates T2 - International Journal of Precision Engineering and Manufacturing-Green Technology N2 - Nowadays, the recycled fine aggregate sourced from construction and demolition waste is not frequently used in manufacturing of epoxy resin coatings. Therefore, the main novelty of the article is to prepare green epoxy resin coatings modified with recycled fine aggregate in a replacement ratio of natural fine aggregate ranged from 20 to 100%. The microstructural properties of the aggregates and epoxy resin were analyzed using micro-computed tomography, scanning electron microscopy and nanoindentation. The macroscopic mechanical properties were examined using pull-off strength tests. The highest improvement of the mechanical properties was observed for epoxy resin coatings modified with 20% of natural fine aggregate and 80% of recycled fine aggregate. It has been found that even 100% of natural fine aggregate can be successfully replaced using the recycled fine aggregate with consequent improvement of the pull-off strength of analyzed epoxy resin coatings. In order to confirm the assumptions resulting from the conducted research, an original analytical and numerical failure model proved the superior behavior of modified coating was developed. KW - Manufacturing KW - Wear KW - Composite KW - Epoxy resin coating KW - Recycled aggregate KW - Green material Y1 - 2022 UR - https://link.springer.com/article/10.1007/s40684-021-00377-w U6 - https://doi.org/10.1007/s40684-021-00377-w SN - 2198-0810 VL - 9 IS - 1 SP - 253 EP - 271 ER - TY - GEN A1 - Aissani, Linda A1 - Fellah, Mamoun A1 - Chadli, Abdel Hakim A1 - Samad, Mohammed Abdul A1 - Cheriet, Abderrahmane A1 - Salhi, Faiza A1 - Nouveau, Corinne A1 - Weiß, Sabine A1 - Obrosov, Aleksei A1 - Alhussein, Akram T1 - Investigating the effect of nitrogen on the structural and tribo-mechanical behavior of vanadium nitride thin films deposited using R.F. magnetron sputtering T2 - Journal of Materials Science N2 - Magnetron sputtering is one of the most commonly used deposition techniques, which has received considerable attention in industrial applications. In particular, owing to its compatibility with conventional fabrication processes, it can produce and fabricate high-quality dense thin films of a wide range of materials. In the present study, nitrogen (N) was combined with pure vanadium in order to form binary nitride to improve its mechanical and tribological performance. To evaluate the influence of nitrogen on the structure of the as-deposited vanadium nitride (VN) coatings, the following techniques were used: XPS, XRD, SEM, AFM and optical profilometry. The residual stresses were determined by the curvature method using Stoney’s formula. The hardness and Young’s modulus were obtained by nanoindentation measurements. The friction behavior and wear characteristics of the films were evaluated by using a ball-on-disk tribometer. The obtained results showed that the N/V ratio increased with increasing the N2 flow rate while the deposition rate decreased. The preferred orientation was changed from (200) to (111) as the N2 flow rate increased with the presence of V–N and V–O binding energies as confirmed by XPS analysis. The nitrogen addition resulted in a columnar morphology and a fine structure with fine surface roughness. The VN thin film containing 49.5 at.% of nitrogen showed the best performance: highest mechanical properties (hardness = 25 GPa), lowest friction coefficient (μ = 0.37) and lowest wear rate (Ws = 2.72 × 10−5 mm3N−1 m−1). A good correlation between the film microstructure, crystallite size, residual stress and mechanical and tribological properties was observed. Y1 - 2021 U6 - https://doi.org/10.1007/s10853-021-06393-0 SN - 1573-4803 SN - 0022-2461 VL - 56 IS - 30 SP - 17319 EP - 17336 ER - TY - GEN A1 - Shapovalov, Oleg A1 - Shapovalova, Mariia A1 - Ossenbrink, Ralf A1 - Heckel, Thomas A1 - Michailov, Vesselin A1 - Weiß, Sabine A1 - Gaal, Mate T1 - Verbessern der Korrosionsbeständigkeit eines hochtemperaturbeständigen Ultraschalldämpfungskörpers mittels Laserstrahl-Auftragschweißen T2 - DVS Berichte 2021 N2 - Während in einem konventionellen Ultraschallprüfkopf ein Kunststoffdämpfungskörper mit Kleber oder Öl an einen Piezoschwinger angekoppelt ist, werden als Hochtemperaturlösung feinporöse sintermetallische Dämpfungsmaterialien mit einer Flüssigglasankopplung eingesetzt. Um dabei das Sintermetall vor dem korrosiven Angriff der Glasschmelze zu schützten, wird am Dämpfungskörper gegenwärtig Gold- oder Platinfolie zeit- und kostenaufwendig appliziert. In der aktuellen Arbeit wurde eine Methode zum Korrosionsschutz der sintermetallischen Oberfläche aus rostfreiem Stahl mittels Laser-Pulverauftragschweißen entwickelt. Im Laufe einer Schweißparameterstudie auf dem Substratmaterial aus massivem rostfreiem Stahl wurde die Eignung unterschiedlicher Auftragsmaterialien auf Nickel- und Kobaltbasis untersucht. Dabei wurde zunächst der Einfluss verschiedener Schweißparameter wie Laserleistung, Vorschubgeschwindigkeit und Pulvermenge auf die Auftragsqualität (Nahtform, Vermischungsgrad, Porosität) metallografisch bewertet. Anschließend wurden die aufgetragenen Schichten hinsichtlich ihrer Korrosionsbeständigkeit getestet. Der Kontakt mit einer flüssigen Glasmischung bei 500 °C hat bei keiner der beschichteten Proben sichtbare Korrosionswirkung gezeigt. Als Resultat der Schweißparameterstudie haben sich besonders die nickelbasierten Pulver als gut geeignete Materialien für den Prozess gezeigt. Die identifizierten Schweißparameter wurden im nächsten Schritt erfolgreich an das sintermetallische Substrat angepasst. Y1 - 2021 UR - https://www.dvs-ev.de/call4papers/abstract.cfm?vid=109&pid=7032 SN - 978-3-96144-147-1 SP - 370 EP - 377 PB - DVS Media GmbH CY - Düsseldorf ER - TY - GEN A1 - Ermilova, Evgeniia A1 - Nikitin, Alexander A1 - Weiß, Sabine ED - Daehn, Glenn ED - Cao, Jian ED - Kinsey, Brad ED - Tekkaya, A. Erman ED - Vivek, Anupam ED - Yoshida, Yoshinori T1 - The Local Strain Evolution for Structured Sheet Metals During Uniaxial Deformation T2 - Forming the Future : Proceedings of the 13th International Conference on the Technology of Plasticity N2 - Structured materials can be progressive alternatives to commonly used flat sheets because of their higher bending stiffness and stability compared to flat sheet metals, made of the same alloy. The application of sheet metals requires accurate information regarding their strength and deformation behavior. Such data are not commonly available and have to be measured by specific test setups and implementation of tests. The aim of this work is to obtain new knowledge about deformation mechanisms of structured sheet metals. Structured sheet metals (SSM) made of conventional deep-drawing steel DC04 were investigated by means of tensile tests. The influence of the structure type arrangement on the deformation behavior was analyzed. The evolution of local strains was analyzed by means of strain gauge measurements as well as 3D-displacement measurements with an ARAMIS highresolution camera system. Local orientation changes in different structural elements were measured using the electron backscatter diffraction technique. KW - structured sheet metals, ssm, tensile test, ARAMIS, strain gauge, EBSD, REM, electron microscopy, DC04 steel Y1 - 2021 SN - 978-3-030-75381-8 SN - 978-3-030-75380-1 SN - 978-3-030-75383-2 U6 - https://doi.org/10.1007/978-3-030-75381-8_143 SN - 2367-1696 SP - 1701 EP - 1711 PB - Springer, Cham ET - 1 ER - TY - GEN A1 - Emdadi, Aliakbar A1 - Bolz, Sebastian A1 - Buhl, Johannes A1 - Weiß, Sabine A1 - Bambach, Markus T1 - Laser Powder Bed Fusion Additive Manufacturing of Fe3Al-1.5Ta Iron Aluminide with Strengthening Laves Phase T2 - Metals Y1 - 2022 U6 - https://doi.org/10.3390/met12060997 SN - 2075-4701 VL - 12 IS - 6 ER - TY - GEN A1 - Shapovalov, Oleg A1 - Heckel, Thomas A1 - Gaal, Mate A1 - Weiß, Sabine T1 - External Acoustical Damping on a Metallic Angle Wedge in a High Temperature Resistant Ultrasonic Probe T2 - Acoustics Australia N2 - Ultrasonic probes for high-temperature applications are provided with metallic wedges, which can withstand the contact with the high temperature of the inspected structure. The ultrasonic signal travels within the wedge and gets reflected from its boundaries, causing interference signals called “ghost echoes”. The current work presents an investigation of the additional damping effect provided by porous sintered metal plates applied onto the surface of the wedge. In particular, the study evaluates the effect of damping plate thickness on the interference signal level at different transmission frequencies. Damping plates made of sintered metal SIKA-R 15 AX were attached to a wedge prototype made of steel 1.4301. The study revealed, that the most effective thickness of damping plates in the selected frequency interval of 1 to 4 MHz is equal to 4 mm. The evaluation of the interference signal has shown that the application of such damping plates to the wedge surface contributes to an additional attenuation of an interference signal of 10 to 30 dB after 500 µs of signal propagation. KW - Ultrasonic Testing KW - High temperature KW - Acoustical damping KW - Angle wedge KW - Ultrasonic probe Y1 - 2022 UR - https://link.springer.com/article/10.1007/s40857-022-00270-9 U6 - https://doi.org/10.1007/s40857-022-00270-9 SN - 1839-2571 VL - 50 IS - 3 SP - 343 EP - 353 ER - TY - GEN A1 - Morozova, Iuliia A1 - Kehm, Christian A1 - Obrosov, Aleksei A1 - Yang, Yitong A1 - Miah, Kamal Uddin Mohammad A1 - Uludintceva, Elena A1 - Fritzsche, Sebastian A1 - Weiß, Sabine A1 - Michailov, Vesselin T1 - On the Heat Treatment of Selective-Laser-Melted 316L T2 - Journal of Materials Engineering and Performance N2 - The effect of heat treatment at various temperatures (650, 850, 1050, and 1100°C) and dwell times (10 min and 1 h) on the metallurgical and microstructural evolution as well as on the related tensile properties of stainless steel 316L processed by selective laser melting (SLM) has been systematically evaluated. The metallurgical and microstructural features such as defects, stability of the columnar–cellular structure and substructure, second phase particles, and phase transformation imparted by SLM and heat treatment have been discussed. It has been shown that the processing conditions specific to SLM significantly alter the kinetics of phase evolution compared to standard welding techniques which affects the accuracy of the prediction. The influence of these characteristics on tensile properties and hardness was elucidated. It was disclosed that with increasing heat treatment temperature there was a gradual increase in elongation but a decrease in strength related to the dislocation density and the development of the microstructure. KW - 316L KW - grain structure KW - phase evolution KW - SLM KW - tensile properties Y1 - 2023 U6 - https://doi.org/10.1007/s11665-022-07404-0 SN - 1544-1024 VL - 32 (2023) IS - 10 SP - 4295 EP - 4305 ER - TY - GEN A1 - Morozova, Iuliia A1 - Królicka, Aleksandra A1 - Obrosov, Aleksei A1 - Yang, Yitong A1 - Doynov, Nikolay A1 - Weiß, Sabine A1 - Michailov, Vesselin T1 - Precipitation phenomena in impulse friction stir welded 2024 aluminium alloy T2 - Materials Science and Engineering: A N2 - Microhardness variations across the friction stir welded (FSW) and impulse friction stir welded (IFSW) AA2024–T351 joints have been elucidated by the transformations of the S–Al2CuMg phase with a special focus on a distinguished hardness peak within the heat-affected zone (HAZ) of the impulse welds. The increase in hardness within the stir zone (SZ) originated from the partial re-precipitation of the initial Guinier-Preston-Bagaryatsky zones (GPB) and metastable S needles, previously dissolved.) Formation and growth of stable S precipitates via coalescence accounted for the softening through the thermo-mechanically affected zone (TMAZ). The peak strengthening within the HAZ of the IFSW joints was mainly caused by the dense needle-shaped S particles, which can be explained by a mutual influence of the process specific temperature and strain cycles. Dislocations and subgrain boundaries introduced to the material due to plastic deformation facilitated the nucleation of strengthening S precipitates in the HAZ. It demonstrates that the impact of deformation should be considered by the characterization of the precipitation development in the HAZ. KW - AA2024 KW - impulse friction stir welding KW - microhardness KW - s precipitation KW - thermal cycle KW - deformation Y1 - 2022 U6 - https://doi.org/10.1016/j.msea.2022.143617 SN - 0921-5093 SP - 1 EP - 11 ER - TY - GEN A1 - Figiel, Paweł A1 - Biedunkiewicz, Anna A1 - Jach, Katarzyna A1 - Obrosov, Aleksei A1 - Garbiec, Dariusz A1 - Bik, Maciej A1 - Sitarz, Maciej A1 - Kucia, Zofia A1 - Pawlyta, Mirosława A1 - Weiß, Sabine T1 - Ti-Mo-xTiC composites manufactured by U-FAST reactive sintering T2 - International Journal of Refractory Metals and Hard Materials N2 - The paper presents the characteristics of Ti-Mo-xTiC composites manufactured under experimentally selected conditions using the upgraded field-assisted sintering technique (U-FAST). Mixtures of microstructural titanium powders and nc-Ti0.9Mo0.1C/C carbide powders protected from oxidation by a carbon shell were subjected to sintering. The powders with nc-Ti0.9Mo0.1C/C contents of 10 and 20 wt% were used. The content of carbon forming the carbon shell was approximately 3 or 40 wt%. Composites with near full density were reinforced with titanium carbides in a Ti-Mo matrix. The composites with the highest content of reinforcing phase are characterized by the highest values of hardness, Young's modulus and wear resistance. Although the hardness of these composites is similar to that of ceramics, their nature is not brittle. Despite the high value of the Young's modulus, the addition of hard particles of the reinforcing phase to the titanium matrix significantly increases the values of the H/E ratio of the composites compared to the reference samples of cp-Ti and Ti6Al4V. A comparison of the research results for the composites with the highest share of titanium carbides showed that lowering the sintering temperature from 1300 to 1150 °C resulted in the inhibition of grain growth, a reduction in composite heterogeneity, composite roughness and hardness as well as a rise in the Young's modulus. An increase in the sintering temperature from 1150 to 1300 °C contributed to the higher high angle grain boundaries (HAGB) content. KW - TiMMCs KW - SPS KW - EBSD KW - Nanoindentation KW - Wear Y1 - 2022 UR - https://www.sciencedirect.com/science/article/pii/S0263436822001846#! U6 - https://doi.org/10.1016/j.ijrmhm.2022.105960 SN - 0263-4368 IS - 108 SP - 1 EP - 14 ER - TY - GEN A1 - Petkov, Nikolay A1 - Bakalova, Totka A1 - Obrosov, Aleksei A1 - Kashkarov, Egor B. A1 - Kormunda, Martin A1 - Kejzlar, Pavel A1 - Bahchedzhiev, Hristo A1 - Dadourek, Karel A1 - Weiß, Sabine T1 - Structural, mechanical, and tribological properties of CrCN coatings obtained by cathodic arc physical vapour deposition technology at different CH4/N2 gas ratio T2 - Thin Solid Films N2 - Chromium carbonitride coatings were deposited by cathodic arc physical vapor deposition technology at a temperature of 300 °C, as were used the reactive gasses CH4 and N2. The structural analysis of the CrN coating showed a polycrystalline structure with mixed CrN and Cr2N phases. All studied coatings, including the CrC exhibits fcc structure. The phases were confirmed by X-ray photoelectron spectroscopy measurements where a surface oxidation was also detected. The increase of the CH4 gas flow during the deposition process leads to a parabolic trend with the highest hardness of 33.5 GPa for the coating deposited at CH4 / N2 = 0.53. At the same time the lowest coefficient of friction for both counterparts Al2O3 and ZrO2 (0.28 and 0.26, respectively) were measured at CH4 / N2 = 1.86. The tribological tests reveal that the wear of the coatings increases with an increasing CH4 flow rate, whereas the coefficient of friction decreases. This observed contradiction is explained by a phenomenon described as the effect of Rebinder. KW - Chromium carbonitride KW - Cathodic arc deposition KW - X-ray diffraction KW - X-ray photoelectron spectroscopy KW - Mechanical properties KW - Wear Y1 - 2023 UR - https://www.sciencedirect.com/science/article/pii/S0040609022005715 U6 - https://doi.org/10.1016/j.tsf.2022.139669 SN - 1879-2731 VL - 766 ER - TY - GEN A1 - Grudinin, V. A. A1 - Bleykher, G. A. A1 - Krivobokov, V. P. A1 - Semyonov, O. V. A1 - Obrosov, Aleksei A1 - Weiß, Sabine A1 - Sidelev, D. V. T1 - Hot target magnetron sputtering enhanced by RF-ICP source: Microstructure and functional properties of CrNx coatings T2 - Vacuum N2 - CrNx coatings were deposited at high rates (100–130 nm/min) using hot Cr target magnetron sputtering enhanced by a radio-frequency inductively coupled plasma (RF-ICP) source in an Ar + N2 atmosphere. Besides separation of inert and reactive atmosphere, the RF-ICP source can be an effective tool for ion assistance in case of coating growth and to tailor film parameters. The effects of nitrogen flow rate and substrate bias potential on microstructure and functional properties of the CrNx coatings were investigated. An increase in nitrogen flow rate favored the formation of a looser microstructure of the coatings, while substrate biasing had the opposite effect. The functional properties were strongly dependent on the phase composition of the CrNx coatings. The change in coating microstructure significantly affected hardness, elastic modulus, adhesion, friction coefficients and corrosion resistance. The results indicated that ion assistance can be a key feature for regulating functional properties in the considered type of coating deposition. Cr2N and CrN compound coatings with high hardness (∼20 GPa) and low corrosion current density (icorr ∼ 3–5·10−9 A/cm2) in a 3.5 wt% NaCl solution were obtained by high-rate deposition. KW - CrN KW - Coatings KW - Hot target KW - Magnetron sputtering KW - High-rate deposition KW - RF-ICP Y1 - 2022 UR - https://www.sciencedirect.com/science/article/pii/S0042207X2200152X U6 - https://doi.org/10.1016/j.vacuum.2022.111020 SN - 1879-2715 VL - 200 ER -