@misc{ShulepovKashkarovStepanovetal., author = {Shulepov, Ivan A. and Kashkarov, Egor B. and Stepanov, Igor B. and Syrtanov, Maxim S. and Sutygina, Alina and Shanenkov, Ivan and Obrosov, Aleksei and Weiß, Sabine}, title = {The Formation of Composite Ti-Al-N Coatings Using Filtered Vacuum Arc Deposition with Separate Cathodes}, series = {Metals}, volume = {7}, journal = {Metals}, number = {11}, issn = {2075-4701}, doi = {10.3390/met7110497}, pages = {13}, abstract = {Ti-Al-N coatings were deposited on high-speed steel substrates by filtered vacuum arc deposition (FVAD) during evaporation of aluminum and titanium cathodes. Distribution of elements, phase composition, and mechanical properties of Ti-Al-N coatings were investigated using Auger electron spectroscopy (AES), X-ray diffraction (XRD), transmission electron microscopy (TEM) and nanoindentation, respectively. Additionally, tribological tests and scratch tests of the coatings were performed. The stoichiometry of the coating changes from Ti0.6Al0.4N to Ti0.48Al0.52N with increasing aluminum arc current from 70 A to 90 A, respectively. XRD and TEM showed only face-centered cubic Ti-Al-N phase with preferred orientation of the crystallites in (220) direction with respect to the sample normal and without precipitates of AlN or intermetallics inside the coatings. Incorporation of Al into the TiN lattice caused shifting of the (220) reflex to a higher 2θ angle with increasing Al content. Low content and size of microdroplets were obtained using coaxial plasma filters, which provides good mechanical and tribological properties of the coatings. The highest value of microhardness (36 GPa) and the best wear-resistance were achieved for the coating with higher Al content, thus for Ti0.48Al0.52N. These coatings exhibit good adhesive properties up to 30 N load in the scratch tests.}, language = {en} } @misc{ObrosovSutyginaManakhovetal., author = {Obrosov, Aleksei and Sutygina, Alina and Manakhov, Anton and Bolz, Sebastian and Weiß, Sabine and Kashkarov, Egor B.}, title = {Oxidation Behavior of Zr-1Nb Corroded in Air at 400 °C after Plasma Immersion Titanium Implantation}, series = {Metals}, volume = {8}, journal = {Metals}, number = {1}, issn = {2075-4701}, doi = {10.3390/met8010027}, pages = {16}, abstract = {In this paper, the influence of plasma immersion titanium implantation into the zirconium alloy Zr-1Nb on the oxidation behavior at 400 °C for 5, 24, 72, and 240 h in air under normal atmospheric pressure (101.3 kPa) was shown. The influence of implantation on the protective properties of the modified layer was shown. The valence of the oxides before and after implantation was analyzed by means of X-ray photoelectron spectroscopy (XPS). Grazing incidence X-ray diffraction (GIXRD) was carried out to examine the phase composition after titanium ion implantation and oxidation. Differential scanning calorimetry (DSC) revealed that titanium implantation exhibited effects of stabilizing the β phase. The formation of the t-ZrO2 and m-ZrO2 was observed during the oxidation of the as-received and modified Zr-1Nb. The measurement of weight gain showed an improvement in oxidation resistance of Ti implanted Zr-1Nb at the oxidation up to 24 h when compared with that of the as-received Zr-1Nb. However, at longer oxidation cycle the oxidation rate of Ti-implanted zirconium alloy is the same with the as-received alloy, which attributed to the layer thickness. Nevertheless, the corrosion of the Ti-implanted alloy is more uniform, while a local corrosion and cracks was detected on the surface of the as-received alloy.}, language = {en} } @misc{SolovievaMiroshnichenkoKovalskiietal., author = {Solovieva, Anastasiya and Miroshnichenko, Svetlana and Kovalskii, Andrey and Permyakova, Elizaveta and Popov, Zakhar and Dvoř{\´a}kov{\´a}, Eva and Kiryukhantsev-Korneev, Philip and Obrosov, Aleksei and Polčak, Josef and Zaj{\´i}čkov{\´a}, Lenka and Shtansky, Dmitry V. and Manakhov, Anton}, title = {Immobilization of Platelet-Rich Plasma onto COOH Plasma-Coated PCL Nanofibers Boost Viability and Proliferation of Human Mesenchymal Stem Cells}, series = {Polymers}, volume = {9}, journal = {Polymers}, number = {12}, issn = {2073-4360}, doi = {10.3390/polym9120736}, pages = {14}, abstract = {The scaffolds made of polycaprolactone (PCL) are actively employed in different areas of biology and medicine, especially in tissue engineering. However, the usage of unmodified PCL is significantly restricted by the hydrophobicity of its surface, due to the fact that its inert surface hinders the adhesion of cells and the cell interactions on PCL surface. In this work, the surface of PCL nanofibers is modified by Ar/CO2/C2H4 plasma depositing active COOH groups in the amount of 0.57 at \% that were later used for the immobilization of platelet-rich plasma (PRP). The modification of PCL nanofibers significantly enhances the viability and proliferation (by hundred times) of human mesenchymal stem cells, and decreases apoptotic cell death to a normal level. According to X-ray photoelectron spectroscopy (XPS), after immobilization of PRP, up to 10.7 at \% of nitrogen was incorporated into the nanofibers surface confirming the grafting of proteins. Active proliferation and sustaining the cell viability on nanofibers with immobilized PRP led to an average number of cells of 258 ± 12.9 and 364 ± 34.5 for nanofibers with ionic and covalent bonding of PRP, respectively. Hence, our new method for the modification of PCL nanofibers with PRP opens new possibilities for its application in tissue engineering.}, language = {en} } @misc{KashkarovNikitenkovSutyginaetal., author = {Kashkarov, Egor B. and Nikitenkov, Nikolay and Sutygina, Alina and Obrosov, Aleksei and Manakhov, Anton and Polčak, Josef and Weiß, Sabine}, title = {Hydrogen absorption by Ti-implanted Zr-1Nb alloy}, series = {International journal of hydrogen energy}, volume = {43}, journal = {International journal of hydrogen energy}, number = {4}, issn = {0360-3199}, doi = {10.1016/j.ijhydene.2017.12.003}, pages = {2484 -- 2491}, abstract = {This paper describes the hydrogenation behavior of Zr-1Nb alloy Ti-implanted by plasma immersion ion implantation (PIII). Hydrogen sorption kinetics of the Ti-modified alloy was investigated under gas-phase hydrogenation at 400 °C for 1 h. The influence of implantation time on the protective properties of the modified layer was shown. The lowest hydrogen absorption as well as the highest hydrogen trapping efficiency was achieved after PIII for 30 min. The main contribution to the reduction of hydrogen permeation is the formation of an oxide layer consisting of mixed TiO2 and ZrO2 on the modified surface of the alloy. X-ray photoelectron spectroscopy (XPS) revealed that PIII titanium oxide exists on the surface in the form of TiO2, which transforms to mixed Ti2O3 and TiO2 after hydrogenation. The thickness of the modified layer increases with implantation time that improves the efficiency of hydrogen trapping. All the absorbed hydrogen is gradually distributed in the modified layer and no hydrides are formed after hydrogenation in Ti-modified Zr-1Nb for 15 and 30 min.}, language = {en} } @misc{KashkarovObrosovSutyginaetal., author = {Kashkarov, Egor B. and Obrosov, Aleksei and Sutygina, Alina and Uludintceva, Elena and Mitrofanov, Andrei and Weiß, Sabine}, title = {Hydrogen Permeation, and Mechanical and Tribological Behavior, of CrNx Coatings Deposited at Various Bias Voltages on IN718 by Direct Current Reactive Sputtering}, series = {Coatings}, volume = {8}, journal = {Coatings}, number = {2}, issn = {2079-6412}, doi = {10.3390/coatings8020066}, pages = {12}, abstract = {In the current work, the microstructure, hydrogen permeability, and properties of chromium nitride (CrNₓ) thin films deposited on the Inconel 718 superalloy using direct current reactive sputtering are investigated. The influence of the substrate bias voltage on the crystal structure, mechanical, and tribological properties before and after hydrogen exposure was studied. It was found that increasing the substrate bias voltage leads to densification of the coating. X-ray diffraction (XRD) results reveal a change from mixed fcc-CrN + hcp-Cr₂N to the approximately stoichiometric hcp-Cr₂N phase with increasing substrate bias confirmed by wavelength-dispersive X-ray spectroscopy (WDS). The texture coefficients of (113), (110), and (111) planes vary significantly with increasing substrate bias voltage. The hydrogen permeability was measured by gas-phase hydrogenation. The CrN coating deposited at 60 V with mixed c-CrN and (113) textured hcp-Cr₂N phases exhibits the lowest hydrogen absorption at 873 K. It is suggested that the crystal orientation is only one parameter influencing the permeation resistance of the CrNx coating together with the film structure, the presence of mixing phases, and the packing density of the structure. After hydrogenation, the hardness increased for all coatings, which could be related to the formation of a Cr₂O₃ oxide film on the surface, as well as the defect formation after hydrogen loading. Tribological tests reveal that hydrogenation leads to a decrease of the friction coefficient by up to 40\%. The lowest value of 0.25 ± 0.02 was reached for the CrNₓ coating deposited at 60 V after hydrogenation.}, language = {en} } @misc{EvdokimovObrosovOssenbrinketal., author = {Evdokimov, Anton and Obrosov, Aleksei and Ossenbrink, Ralf and Weiß, Sabine and Michailov, Vesselin}, title = {Mechanical properties of dissimilar steel-aluminum weld}, series = {Materials Science and Engineering: A}, volume = {Volume 722}, journal = {Materials Science and Engineering: A}, issn = {0921-5093}, doi = {https://doi.org/10.1016/j.msea.2018.03.019}, pages = {242 -- 254}, abstract = {Knowledge of the properties of dissimilar welds is of great significance for the development of multi-material lightweight structures. In this study, stainless steel (1.4301) and aluminum alloy (6082-T6) sheets were welded in overlap configuration in keyhole mode. The resulting weld metals were investigated with respect to their mechanical properties. Several samples were cut out of different locations along the welds and their cross-sections were subjected to indentation testing and energy dispersive X-ray (EDS) analysis. Young's modulus E, yield stress σy, and strain hardening exponent n, were determined by means of reverse analysis of the indentation load (P) - depth (h) curves, allowing construction of true stress - true strain relations. An essential increase in yield stress in comparison to the one of the base alloys was observed inside the weld metal. In contrary, Young's modulus and strain hardening exponent of the welds were almost identical to corresponding values of the base steel metal. Due to the sensitivity of yield stress to the aluminum content, slight variations of the welding parameters lead to significant changes in elastic-plastic behavior of the weld metal.}, language = {en} } @misc{KashkarovNikitenkovSutyginaetal., author = {Kashkarov, Egor B. and Nikitenkov, Nikolay and Sutygina, Alina and Syrtanov, Maxim S. and Zakharchenko, S. and Obrosov, Aleksei}, title = {Influence of Plasma-Immersion Titanium-Ion Implantation on the Kinetics of Hydrogen Penetration into E110 Zirconium Alloy}, series = {Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques}, volume = {12}, journal = {Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques}, number = {3}, issn = {1819-7094}, doi = {10.1134/S102745101803031X}, pages = {570 -- 575}, abstract = {The influence of plasma-immersion titanium-ion implantation on the hydrogen saturation of E110 zirconium alloy is described. Titanium ions are implanted from the metal plasma of an arc discharge at an accelerating-pulse bias potential of 1.5 kV (the pulse-repetition frequency is 100 kHz, and the pulse length is 5 μs) for 30 min. The phase composition, morphology, and valence state of the alloy surface layer are studied. Comparative analysis of changes in the hardness and wear resistance of the alloy subjected to implantation is performed. It is demonstrated that the rate of hydrogen penetration into the surface-doped alloy decreases substantially at a gas-phase hydrogenation temperature of 400°C.}, language = {en} } @misc{PetkovKashkarovObrosovetal., author = {Petkov, Nikolay and Kashkarov, Egor B. and Obrosov, Aleksei and Bakalova, Totka and Kejzlar, Pavel and Bahchedzhiev, Hristo}, title = {Influence of Bias Voltage and CH4/N2 Gas Ratio on the Structure and Mechanical Properties of TiCN Coatings Deposited by Cathodic Arc Deposition Method}, series = {Journal of Materials Engineering and Performance}, volume = {28}, journal = {Journal of Materials Engineering and Performance}, number = {1}, issn = {1544-1024}, doi = {10.1007/s11665-018-3754-3}, pages = {343 -- 354}, abstract = {This article presents a study of the influence of the bias voltage and CH4/N2 gas ratio on the structure and mechanical properties of TiCN coatings. The coatings are deposited by cathodic arc deposition technology from Ti cathodes under an atmosphere of a mixture of CH4 and N2 gasses. XRD analysis shows that an increase in the methane flow changes the preferential orientation of the coating from (111) to (200) and results in a refinement of the structure (grain size reduction from 23 to 7 nm). SEM analysis shows that the coatings are stoichiometric. It was demonstrated that the bias voltage has an influence on the grain size, hardness and elasticity module. The highest hardness value of 52.5 GPa was measured at the coatings lacking a clear preferential orientation. The adhesion of the coatings showed a critical load in the range of 29-64 N.}, language = {en} } @misc{ObrosovSutyginaKashkarovetal., author = {Obrosov, Aleksei and Sutygina, Alina and Kashkarov, Egor B. and Weiß, Sabine}, title = {Oxidation behavior of Zr-1Nb in air at 400°C after Titanium Plasma Immersion Ion Implantation}, pages = {1}, abstract = {Zirconium alloys have been widely used in nuclear reactors due to low thermal neutron capture cross-section, excellent corrosion resistance and acceptable mechanical properties [1, 2]. Nowadays several methods apply for improving hydrogen and corrosion resistance such as addition of stabilizing additives (yttrium) [3, 4], deposition of thin solid films [5, 6], micro-arc oxidation [7] and modification of the surface by electron beam [8, 9]. Despite the multiplicity of the methods hydrogen embrittlement is still a pressing issue. Previous results [10, 11] have shown the positive influence of plasma immersion titanium implantation on the hydrogenation behavior of Zr-1Nb and Zr-2.5 Nb. After Ti implantation hydrogen preferably accumulates in the modified surface layer comprising the implanted Ti. Furthermore, the hydrogen concentration is considerably less inside the zirconium modified sample than in the as-received samples. The integration of elements into the zirconium lattice can influence the valence of the surface and change corrosion and oxidation rates of the alloys. So it is very important not to decrease the zirconium oxidation resistance due to Ti implantation. Therefore, the purpose of this research is to study of the influence of Ti implantation on surface morphology, oxidation rate and phase structure of the Zr-1Nb alloy after oxidation on air at 400 0C for 5, 24, 72 and 240 h. The surface structure of the samples and their elemental composition were investigated with the scanning electron microscope Mira II XMH (Tescan) with energy dispersive x-ray spectroscopy system (EDS). X-ray photoelectron spectroscopy (XPS), differential scanning calorimetry (DSC) as well as X-ray diffraction (XRD) was used to characterise the influence of titanium implantation on the oxidation behaviour. The results show that the oxidation kinetics after Ti modification of the zirconium alloy changed. Although the weight gain of the implanted sample remains approximately the same, it can be considered that Ti implantation stabilizes the oxide layer and has beneficial influence on the oxidation protection of Zr-1Nb.}, language = {en} } @misc{KashkarovRyabchikovKurochkinetal., author = {Kashkarov, Egor B. and Ryabchikov, Alexander I. and Kurochkin, Alexander and Syrtanov, Maxim S. and Shevelev, Alexey and Obrosov, Aleksei and Weiß, Sabine}, title = {Hydrogen Interaction with Deep Surface Modified Zr-1Nb Alloy by High Intensity Ti Ion Implantation}, series = {Metals}, volume = {8}, journal = {Metals}, number = {12}, issn = {2075-4701}, doi = {10.3390/met8121081}, abstract = {A deep surface modified TiZr layer was fabricated by high-intensity low-energy titanium ion implantation into zirconium alloy Zr-1Nb. Gas-phase hydrogenation was performed to evaluate protective properties of the modified layer against hydrogen permeation into Zr-1Nb alloy. The effects of ion implantation and hydrogen on microstructure, phase composition and elemental distribution of TiZr layer were analyzed by scanning electron microscopy, X-ray diffraction, and glow-discharge optical emission spectroscopy, respectively. It was revealed that TiZr layer (~10 μm thickness) is represented by α′ + α(TiZr) lamellar microstructure with gradient distribution of Ti through the layer depth. It was shown that the formation of TiZr layer provides significant reduction of hydrogen uptake by zirconium alloy at 400 and 500 °C. Hydrogenation of the modified layer leads to refinement of lamellar plates and formation of more homogenous microstructure. Hydrogen desorption from Ti-implanted Zr-1Nb alloy was analyzed by thermal desorption spectroscopy. Hydrogen interaction with the surface modified TiZr layer, as well as its resistance properties, are discussed.}, language = {en} } @misc{GuntherYasenchukChekalkinetal., author = {Gunther, Victor and Yasenchuk, Yuri and Chekalkin, Timofey and Marchenko, Ekaterina and Gunther, Sergey and Baigonakova, Gulsharat and Hodorenko, Valentina and Kang, Ji-hoon and Weiß, Sabine and Obrosov, Aleksei}, title = {Formation of pores and amorphous-nanocrystalline phases in porous TiNi alloys made by self-propagating high-temperature synthesis (SHS)}, series = {Advanced Powder Technology}, volume = {30}, journal = {Advanced Powder Technology}, number = {4}, issn = {0921-8831}, doi = {10.1016/j.apt.2018.12.011}, pages = {673 -- 680}, abstract = {The objective of this study was to examine the mechanism how the surface of porous TiNi compounds produced by SHS method evolves. The prepared samples were investigated using light-microscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive x-ray spectroscopy (EDS). The results indicated that the surface of all pores is represented by a granular stratum due to dendrite liquation by peritectic crystallization mechanism. The voids of 2-15 μm in size are formed owing to a capillary spreading of the liquid. Reaction gases with dissociated carbon, nitrogen, and oxygen are responsible for heat-and-mass transfer through the forming pores. High pressure-temperature effect of reaction gases on the melt causes the forming voids to coalesce, as well as transfers the peritectic liquid (PL) throughout the open pores catalyzing a distinctive spitted topography. It is through the chemisorption of gasiform nonmetallics by the pore surface melt, where these impurities are chemically bound, that it was formed a massive corrosion-resistant amorphous-nanocrystalline stratified shell deduced as an intermetallic oxycarbonitride layer.}, language = {en} } @misc{KashkarovSyrtanovMurashkinaetal., author = {Kashkarov, Egor B. and Syrtanov, Maxim S. and Murashkina, Tatyana and Kurochkin, Alexander and Shanenkova, Yulia and Obrosov, Aleksei}, title = {Hydrogen Sorption Kinetics of SiC-Coated Zr-1Nb Alloy}, series = {Coatings}, volume = {9}, journal = {Coatings}, number = {1}, issn = {2079-6412}, doi = {10.3390/coatings9010031}, pages = {10}, abstract = {This paper describes the influence of silicon carbide (SiC) coating on hydrogen sorption kinetics of zirconium alloy E110 (Zr-1Nb). Amorphous SiC coating of 1.5-μm thickness was deposited on Zr-1Nb alloy substrate by direct current magnetron sputtering of composite cathode. Hydrogen absorption by SiC-coated Zr-1Nb alloy significantly decreased due to low hydrogen permeability of the coating. Hydrogenation tests show that SiC coating provides protective properties against hydrogen permeation in the investigated temperature range of 350-450 °C. It was shown that hydrogenation of uncoated Zr-1Nb leads to formation of δ hydrides at 350 °C and δ and γ hydrides at higher temperatures whereas in the SiC-coated Zr-1Nb alloy only δ hydrides formed. Gradient hydrogen distribution through the SiC coating and H trapping in the carbon-rich interface was observed. The adhesion strength of the coating was ~5 N. Hydrogenation up to 450 °C for 5 h does not degrade the adhesion properties during scratch testing.}, language = {en} } @misc{YasenchukGuntherMarchenkoetal., author = {Yasenchuk, Yuri and Gunther, Victor and Marchenko, Ekaterina and Chekalkin, Timofey and Baigonakova, Gulsharat and Hodorenko, Valentina and Gunther, Sergey and Kang, Ji-hoon and Weiß, Sabine and Obrosov, Aleksei}, title = {Formation of mineral phases in self-propagating high-temperature synthesis (SHS) of porous TiNi alloy}, series = {Materials Research Express}, volume = {6}, journal = {Materials Research Express}, number = {5}, issn = {2053-1591}, doi = {10.1088/2053-1591/ab01a1}, pages = {13}, abstract = {The complex structural-phase composition, morphology and elemental composition of surface and nonmetallics in porous TiNi compounds produced by self-propagating high-temperature synthesis (SHS) in a flow reactor in the layer-by-layer combustion mode were analyzed. The samples were investigated using light microscopy (LM), X-ray diffraction (XRD), scanning electron microscopy (SEM), scanning transmission electron microscopy (STEM), and energy dispersive X-ray spectroscopy (EDS). The findings indicate that in addition to the TiNi and Ti2Ni intermetallic constituents, the pore's surface contains numerous Ti4Ni2(O,N,C) nanocrystalline oxycarbonitrides, spinels, polysilicates, and residual amorphous phases. The elemental composition of the surface and crystalline inclusions is investigated by the EDS method. LM, SEM, TEM, and EDS instrumental examination revealed the entire surface comprising a continuous shell of intermetallic superficial bulb-shaped structures, as well as crystalline inclusions of polysilicates and spinels in the intergranular peritectic phase. Prominent morphology was confirmed to appear throughout the pore's surface owing to the interaction of the peritectic liquid (PL) with reaction gases. The epitaxial, nanocrystalline strata of intermetallic oxycarbonitrides were shown to have the intricate nature. Reaction gases chemisorbed by the PL are responsible for the continuous and dense substrate, which ultrafine structure modulates a high corrosion resistance. On the contrary, the sparse and foamy overlay resulted from a convective transfer of the PL by reaction gases facilitates in vivo bio-integration of the alloy. Overall, this sheds light on and may be more indicative of the complex role of superficial strata and nonmetallic crystals in enhanced biocompatibility of the unwrought porous TiNi alloy.}, language = {en} } @misc{ShtinNovikovChekalkinetal., author = {Shtin, Valentin and Novikov, Valeriy and Chekalkin, Timofey and Gunther, Victor and Marchenko, Ekaterina and Choynzonov, Evgeniy and Baik Kang, Seung and Jong Chang, Moon and Hoon Kang, Ji and Obrosov, Aleksei}, title = {Repair of Orbital Post-Traumatic Wall Defects by Custom-Made TiNi Mesh Endografts}, series = {Journal of Functional Biomaterials}, volume = {10}, journal = {Journal of Functional Biomaterials}, number = {3}, issn = {2079-4983}, doi = {10.3390/jfb10030027}, pages = {9}, abstract = {Repairs of orbital post-traumatic and extensive malignant defects remain a major surgical challenge, in view of follow-up outcomes. Incorrect surgical management of injured facial structures results in cosmetic, ophthalmic, and social aftereffects. A custom-made knitted TiNi-based mesh (KTNM) endograft was employed to overcome post-surgical complications and post-resected lesions of the orbital area. Preoperative high-resolution computed tomography (CT) imaging and CAD modelling were used to design the customized KTNM in each case. Twenty-five patients underwent surgery utilizing the suggested technique, from 2014 to 2019. In all documented cases, resolution of the ophthalmic malfunction was noted in the early period. Follow-up observation evidenced no relapsed enophthalmos, hypoglobus, or diplopia as late complications. The findings emanating from our clinical observations allow us to claim that the KTNM indicated a high level of biocompatibility. It is simply modified intraoperatively to attach any desired shape/size for implantation and can also be screw-fixed, providing a good supporting ability. The KTNM precisely renders orbitozygomatic outlines and orbital floor, thus recovering the anatomical structure, and is regarded as an attractive alternative to Ti-based meshes and plates. Additionally, we report one of the studied cases, where good functional and cosmetic outcomes have been achieved.}, language = {en} } @misc{RyabchikovKashkarovShevelevetal., author = {Ryabchikov, Alexander I. and Kashkarov, Egor B. and Shevelev, Alexey and Obrosov, Aleksei and Sivin, D. O.}, title = {Surface modification of Al by high-intensity low-energy Ti-ion implantation: Microstructure, mechanical and tribological properties}, series = {Surface and Coatings Technology}, volume = {372}, journal = {Surface and Coatings Technology}, issn = {0257-8972}, doi = {10.1016/j.surfcoat.2019.05.020}, pages = {1 -- 8}, abstract = {A high-intensity metal ribbon ion beam was generated using plasma immersion extraction and the acceleration of the metal ions with their subsequent ballistic focusing using a cylindrical grid electrode under a repetitively pulsed bias. To generate the dense metal plasma flow, two water-cooled vacuum arc evaporators with Ti cathodes were used. The ion current density reached 43 mA/cm2 at the arc discharge current of 130 A. High-intensity ion implantation (HIII) with a low ion energy ribbon beam was used for the surface modification of the aluminium. The irradiation fluence was changed from 1.5 × 1020 ion/cm2 to 4 × 1020 ion/cm2 with a corresponding increase in the implantation temperature from 623 to 823 K. The structure and composition of the Ti-implanted aluminium were studied using X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDX). The mechanical properties and wear resistance were measured using nanoindentation and "pin-on-disk" testing, respectively. It was shown that the HIII method can be used to form a deep intermetallic Al3Ti layer. It has been established that a thin (0.4 μm) modified layer with a hcp Ti(Al) structure is only formed on the surface at 623 K, while the formation of the ordered Al3Ti intermetallic phase occurs at the implantation temperatures of 723 and 823 K. Despite the significant ion sputtering of the surface, the thickness of the modified layer increases from ~1 μm to ~6 μm, and the implantation temperature rises from 723 to 823 K. It was found that the homogeneous intermetallic Al3Ti layer with a thickness of up to 5 μm was formed at 823 К. The mechanical and tribological properties of the aluminium were substantially improved after HIII. For the Ti-implanted aluminium, the hardness of the surface layer increases from 0.4 GPa (undoped Al) to 3.5-4 GPa, while the wear resistance increases by more than an order of magnitude.}, language = {en} } @misc{FellahHezilDjellabietal., author = {Fellah, Mamoun and Hezil, Naouel and Djellabi, Ridha and Samad, Mohammed Abdul and Touhami, Mohamed Zine and Montagne, Alex and Iost, Alain and Obrosov, Aleksei and Weiß, Sabine}, title = {Rapid and enhanced recovery of poly-dispersed nonionic surfactant (TX-100) from organic mediums using dehydrated and rehydrated kaolin}, series = {Applied Clay Science}, volume = {177}, journal = {Applied Clay Science}, issn = {0169-1317}, doi = {10.1016/j.clay.2019.05.004}, pages = {43 -- 50}, abstract = {The recovery of surfactants from organic mediums is of great economic and environmental interests in the field of petrochemicals sector. The aim of this study was to recover poly-dispersed nonionic surfactant (TX-100) from organic medium by the use of dehydrated and rehydrated kaolin. It was found that the presence of water after kaolin rehydration decreases considerably the amount of TX-100 adsorption from 28.7 μmol.g-1 onto dehydrated kaolin to 23.4 μmol.g-1 onto rehydrated kaolin. The estimation of the number of statistical layers of water deposited on kaolin was observed to be about 7 to 9. The effect of type of solvents (heptane, cyclohexane and benzene) on the adsorption onto rehydrated kaolin revealed a reduction in the adsorbed quantity; the adsorbed amounts were found to be 28.7 μmol.g-1, 26.7 μmol.g-1 and 24.2 μmol.g-1 in heptane, cycloheptane and benzene phases, respectively. On the other hand, it was observed that a temperature increased from 20 °C to 35 °C and 45 °C negatively affects the adsorption of TX-100 onto dehydrated and/or hydrated kaolin in heptane medium.}, language = {en} } @misc{SanthanakrishnanBalakrishnanObrosovKukeetal., author = {Santhanakrishnan Balakrishnan, Venkateswaran and Obrosov, Aleksei and Kuke, Felix and Seidlitz, Holger and Weiß, Sabine}, title = {Influence of metal surface preparation on the flexural strength and impact damage behaviour of thermoplastic FRP reinforced metal laminate made by press forming}, series = {Composites Part B: Engineering}, volume = {173}, journal = {Composites Part B: Engineering}, issn = {1359-8368}, doi = {10.1016/j.compositesb.2019.05.094}, abstract = {In this paper the relationship between surface energy and flexural strength of metal laminate made by reinforcing glass fibre reinforced polymer on steel surfaces was investigated. Sand blasting was performed on 22MnB5 steel surface. This steel was stacked together with layers of unidirectional glass/polyamide-6 prepreg, followed by pressing in a hot press. Influenced parameters are pressure, temperature and time. 3D profilometer analysis was used to investigate the roughness profile on the surface of the steel generated by the sand blasting. The surface energy of the steel surface was calculated from a set of contact angles measured by three different liquids. To identify the optimal surface treatment, the variation of surface energy, flexural strength and roughness of the steel surface was determined as function of the surface treatment. Surface roughness (Ra of 1.08 μm), results indicate that increasing surface roughness leads to improvement in flexural modulus. The increase further leads to decrease in flexural modulus. In addition, the influence of surface energy and flexural strength on the impact damage behaviour was investigated too. The results showed that the sample with highest flexural modulus had the lowest impact-induced damage area.}, language = {en} } @misc{FellahHezilSamadetal., author = {Fellah, Mamoun and Hezil, Naouel and Samad, Mohammed Abdul and Montagne, Alex and Kosman, Stephania and Megias, Alberto and Iost, Alain and Obrosov, Aleksei and Weiß, Sabine}, title = {Biotribocorrosion behaviour of newly developed nanostructured near β-types Titanium based Alloys for Biomedical Applications}, series = {nanoMAT2019 - 2nd International Conference on Nanomaterials and Their Applications}, journal = {nanoMAT2019 - 2nd International Conference on Nanomaterials and Their Applications}, pages = {170}, abstract = {The biotribocorrosion behavior of newly developed nanocristalline near β-types Ti-15Nb and Ti-15Mo alloys surfaces, sintered by powder metallurgy and sequentially milled, has been investigated in SBF simulated body fluid (PBS solution) at OCP, an applied potential in the passive region and EIS. Reciprocating sliding tests using a ball-on-plate tribometer under differentes applied loads 3, 7 and 10 N load and anodic potentials were applied to evaluate the effect of applied lad and the effect of Nb and Mo elements on tribocorrosion behaviors of samples. Results showed that, Ti-Nb exhibited better anticorrosive properties than Ti-Mo. Under tribological action the nanostructured both of alloys showed similar friction coefficient, while Ti-Nb present lower tendency to corrosion compared to Ti-Mo. Furthermore, Nb diffusion increased the repassivation rate with respect to Ti-Mo surfaces due to its stable passive film. Due to the high chemical reaction rate in β-type Ti-15Mo alloy as compared to Ti-15Nb. The β- Ti-15Nb showed lower volume loss, lower friction coefficient values and exhibited better corrosion resistance during tribocorrosion tests than Ti-15Mo. Prevailing electrochemical conditions between -1 and 2 V influences the wear accelerated corrosion by increasing it with the applied potential and slightly increases the mechanical wear. Also, wear accelerated corrosion can be predicted by existing models as a function of electrochemical and mechanical parameters of the titanium alloys. However, considering biomedical applications, the β- Ti15 Mo and Ti15Nb alloys may be good candidates with low elastic modulus and without toxic alloying elements.}, language = {en} } @misc{ObrosovYasenchukMarchenkoetal., author = {Obrosov, Aleksei and Yasenchuk, Yuri and Marchenko, Ekaterina and Gunther, Victor and Radkevich, Andrey and Kokorev, Oleg and Gunther, Sergey and Baigonakova, Gulsharat and Hodorenko, Valentina and Chekalkin, Timofey and Kang, Ji-hoon and Weiß, Sabine}, title = {Biocompatibility and Clinical Application of Porous TiNi Alloys Made by Self-Propagating High-Temperature Synthesis (SHS)}, series = {Materials}, volume = {12}, journal = {Materials}, number = {15}, issn = {1996-1944}, doi = {10.3390/ma12152405}, pages = {25}, abstract = {Porous TiNi alloys fabricated by self-propagating high-temperature synthesis (SHS) are biomaterials designed for medical application in substituting tissue lesions and they were clinically deployed more than 30 years ago. The SHS process, as a very fast and economically justified route of powder metallurgy, has distinctive features which impart special attributes to the resultant implant, facilitating its integration in terms of bio-mechanical/chemical compatibility. On the phenomenological level, the fact of high biocompatibility of porous SHS TiNi (PTN) material in vivo has been recognized and is not in dispute presently, but the rationale is somewhat disputable. The features of the SHS TiNi process led to a multifarious intermetallic Ti4Ni2(O,N,C)-based constituents in the amorphous-nanocrystalline superficial layer which entirely conceals the matrix and enhances the corrosion resistance of the unwrought alloy. In the current article, we briefly explore issues of the high biocompatibility level on which additional studies could be carried out, as well as recent progress and key fields of clinical application, yet allowing innovative solutions.}, language = {en} } @misc{FellahHezilSamadetal., author = {Fellah, Mamoun and Hezil, Naouel and Samad, Mohammed Abdul and Djellabi, Ridha and Montagne, Alex and Mejias, Alberto and Kossman, Stephania and Iost, Alain and Purnama, Agung and Obrosov, Aleksei and Weiß, Sabine}, title = {Effect of Molybdenum Content on Structural, Mechanical, and Tribological Properties of Hot Isostatically Pressed β-Type Titanium Alloys for Orthopedic Applications}, series = {Journal of Materials Engineering and Performance}, volume = {28}, journal = {Journal of Materials Engineering and Performance}, number = {10}, issn = {1059-9495}, doi = {10.1007/s11665-019-04348-w}, pages = {5988 -- 5999}, abstract = {Aiming to develop alloys with better properties for orthopedic applications, the focus of the present research was to evaluate the effect of Mo at.\% content on structural, mechanical, and tribological properties of hot isostatically pressed Ti-xMo (x = 4, 8, 12, 15, and 20 at.\%) alloys. The structural evolution, mechanical properties, and tribological behavior of the nanostructured Ti-xMo alloys were evaluated using x-ray diffraction, scanning electron microscope, and ball-on-disk tribometer. Wear tests were conducted under different applied loads of 2, 8, and 16 N. Experimental results indicated that the structural evolution and morphological changes of the milled alloys were sensitive to their molybdenum (Mo) content. The morphological characterization showed that the crystallite size and the particle size decreased with increasing Mo content (at.\%) reaching the lowest values of 27 and 26 nm in the case of Ti-15Mo and Ti-20Mo, respectively. On the other hand, the coefficient of friction and wear rates were found to be decreasing with increasing Mo content.}, language = {en} } @misc{ObrosovKashkarovSharmaetal., author = {Obrosov, Aleksei and Kashkarov, Egor B. and Sharma, A. and Weiß, Sabine}, title = {Microstructure and defect structure of Zr-1Nb alloy deep surface modified by high Intensity Ti Ion implantation}, series = {MC Microscopy Conference, 01-05 September 2019, Berlin, Abstracts}, journal = {MC Microscopy Conference, 01-05 September 2019, Berlin, Abstracts}, address = {Berlin}, pages = {86}, abstract = {A deep surface modified TiZr layer was fabricated by high-intensity low-energy titanium ion implantation into zirconium alloy Zr-1Nb alloy with the various dose in the range of (5.4-9.56) × 1020 ion/cm2. The gradient distribution of titanium as well as vacancy type defects were analysed. The effects of ion implantation on microstructure, phase composition and elemental distribution of TiZr layer were analysed by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and glow-discharge optical emission spectroscopy, respectively. The results show the appearance of Zr-Ti intermetallic phases of different stoichiometry after Ti implantation. The intermetallic phases are transformed from both Zr0.7Ti0.3 and Zr0.5Ti0.5 to single Zr0.6Ti0.4 phase with the increase in the implantation dose. The depth of Ti penetration into the bulk of Zr increases from 6 to 13 μm with the implantation dose. The higher current density (170 mA/cm2) leads to the increase in the grain size and surface roughness. It was revealed that TiZr layer (~10 μm thickness) is represented by α′ + α(TiZr) lamellar microstructure with gradient distribution of Ti through the layer depth. Transmission electron microscopy was used for investigation of the physical basis of Ti diffusion and its influence on the evolution of the defect structure after surface modification. Furthermore, it was found that on the surface between substrate and implanted layer was found an amorphous layer, which occur as a result of further stress accumulations from the higher implantation doses.}, language = {en} } @misc{ShevelevKashkarovRyabchikovetal., author = {Shevelev, Alexey and Kashkarov, Egor B. and Ryabchikov, Alexander I. and Syrtanov, Maxim S. and Obrosov, Aleksei}, title = {Surface Modification of E110 Alloy by High-Intensity Low Ion Energy Cr Implantation}, series = {The 21st International Conference on Surface Modification of Materials by Ion Beams, 25-30 August 2019}, journal = {The 21st International Conference on Surface Modification of Materials by Ion Beams, 25-30 August 2019}, address = {Tomsk}, pages = {109 -- 109}, abstract = {The Fukushima disaster has strongly effected on nuclear energetics and their progress [1]. It pointed to a crucial oxidation and subsequent destruction of nuclear fuel claddings in light-water reactors in the case of loss of coolant accident conditions. Surface modification is one of the promising approaches to protect Zr alloys in normal operation and accident conditions of nuclear reactors [2]. Surface modified layers or coatings forming chromia during oxidation is of greatest interest since it meets the basic requirements for accident tolerant fuel materials [3]. The aim of this research is to study the possibility of deep surface modification of zirconium alloy E110 by high intensity ion implantation using low energy metal ion beam. The formation of the metal ion beams is provided by the application of negatively pulsed bias (1.5 kV) to the system immersed in the chromium vacuum arc plasma. The structure and composition of Cr-implanted zirconium alloy were studied by X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy. The mechanical properties and wear resistance were measured by nanoindentation and «ball on disk» testing, respectively. The influence of implantation temperature on the phase composition, microstructure, and mechanical properties as well as on the corrosion behavior of Cr-implanted zirconium alloy under high-temperature oxidation (up to 1100÷1200 °C) have been described.}, language = {en} } @misc{FellahHezilDekhiletal., author = {Fellah, Mamoun and Hezil, Naouel and Dekhil, Leila and Samad, Mohammed Abdul and Djellabi, Ridha and Kosman, Stephania and Montagne, Alex and Iost, Alain and Obrosov, Aleksei and Weiß, Sabine}, title = {Effect of sintering temperature on structure and tribological properties of nanostructured Ti-15Mo alloy for biomedical applications}, series = {Transactions of Nonferrous Metals Society of China}, volume = {29}, journal = {Transactions of Nonferrous Metals Society of China}, number = {11}, issn = {1003-6326}, doi = {10.1016/S1003-6326(19)65137-X}, pages = {2310 -- 2320}, abstract = {The effect of sintering temperature (1073-1373 K) on the structural and tribological properties of nanostructured ball-milled β-type Ti-15Mo samples was investigated. The prepared samples were characterized using various apperatus such as X-ray diffractometer, scanning electron microscope (SEM) and ball-on-plate type oscillating tribometer. Wear tests were conducted under different applied loads (2, 8 and 16 N). Structural results showed that the mean pore and crystallite size continuously decreased with increasing sintering temperature to reach the lowest values of 4 nm and 29 nm at 1373 K, respectively. The relative density of the sintered sample at 1373 K was as high as 97.0\%. Moreover, a higher sintering temperature resulted in higher relative density, greater hardness and elastic modulus of the sample. It was observed that both the friction coefficient and wear rate were lower in the sample sintered at 1373 K which was attributed to the closed porosity.}, language = {en} } @misc{KashkarovRyabchikovSyrtanovetal., author = {Kashkarov, Egor B. and Ryabchikov, Alexander I. and Syrtanov, Maxim S. and Obrosov, Aleksei and Zacharchenko, S.}, title = {ФОРМИРОВАНИЕ ГЛУБОКИХ МОДИФИЦИРОВАННЫХ СЛОЕВ TIZR НА ПОВЕРХНОСТИ ЦИРКОНИЕВОГО СПЛАВА Э110 МЕТОДОМ ВЫСОКОИНТЕНСИВНОЙ ИОННОЙ ИМПЛАНТАЦИИ}, series = {24rd International Conference on Ion-Surface Interactions}, journal = {24rd International Conference on Ion-Surface Interactions}, address = {Moscow}, pages = {190 -- 193}, abstract = {This work describes the effect of high-intensity low ion energy implantation on the structure and properties of the surface modified layer forming on zirconium alloy. The influence of irradiation dose on the microstructure, phase composition, thickness and mechanical properties of surface modified zirconium alloy were investigated.}, language = {ru} } @misc{NaumovMorozovaRylkovetal., author = {Naumov, Anton and Morozova, Iuliia and Rylkov, Evgenii and Obrosov, Aleksei and Isupov, Fedor and Michailov, Vesselin and Rudskoy, Andrey I.}, title = {Metallurgical and Mechanical Characterization of High-Speed Friction Stir Welded AA 6082-T6 Aluminum Alloy}, series = {Materials}, volume = {12}, journal = {Materials}, number = {24}, issn = {1996-1944}, doi = {10.3390/ma12244211}, pages = {16}, abstract = {The objective of this study was to investigate the effect of the high welding speed on the mechanical properties and their relations to microstructural characteristics of butt friction stir welded joints with the use of 6082-T6 aluminum alloy. The aluminum sheets of 2.0 mm thick were friction stir welded at low (conventional FSW) and high welding speeds (HSFSW) of 200 and 2500 mm/min, respectively. The grain size in the nugget zone (NZ) was decreased; the width of the softened region was narrowed down as well as the lowest microhardness value located in the heat-affected zone (HAZ) was enhanced by HSFSW. The increasing welding speed resulted in the higher ultimate tensile strength and lower elongation, but it had a slight influence on the yield strength. The differences in mechanical properties were explained by analysis of microstructural changes and tensile fracture surfaces of the welded joints, supported by the results of the numerical simulation of the temperature distribution and material flow. The fracture of the conventional FSW joint occurred in the HAZ, the weakest weld region, while all HSFSW joints raptured in the NZ. This demonstrated that both structural characteristics and microhardness distribution influenced the actual fracture locations.}, language = {en} } @misc{FellahHezilDekhiletal., author = {Fellah, Mamoun and Hezil, Naouel and Dekhil, Leila and Samad, Mohammed Abdul and Montagne, Alex and Mejias, Alberto and Iost, Alain and Obrosov, Aleksei and Weiß, Sabine}, title = {Structural characterization of developed near β-Type Titanium Alloys (Ti-25NbxZr) for biomedical Applications}, series = {3rd International Conference on Mechanics and Materials : ICMM'2019 11-12 November 2019. Setif, Algeria, Abstracts book}, journal = {3rd International Conference on Mechanics and Materials : ICMM'2019 11-12 November 2019. Setif, Algeria, Abstracts book}, address = {Setif, Algeria}, pages = {224 -- 225}, abstract = {The osteoarthritis and degenerative diseases osteoporosis as well as trauma lead to the bone mechanical properties degradation due to absence of normal biological self healing processes or excessive loading [1-5]. These problems solution are artificial biomaterials, as surgical implantation of appropriate shapes helps restore function for the otherwise functionally compromised structures [1-5]. Biocompatibility is considered to be optimal once tissue neoformation and later function occurs around implantable devices [6]. The efficacy of biomaterials implants is determined mostly by their surface characteristics such as microstructure, surface morphology, composition and biological properties [2]. Aiming to develop alloys with better properties for orthopedic applications, the focus of the present research was to evaluate the effect of Zr at. \% content on structural, mechanical and tribological properties of hot isostatically pressed Ti-25Nb-xZr (x = 5, 10, 15, 20 and 25 at. \%) alloys. The structural evolution, and mechanical properties of the nanostructured Ti-Nb-xZr alloys were evaluated using X-Ray diffraction, scanning electron microscope. The mechanical properties were performed using Vickers hardness and berkovich nanoindentation. Experimental results indicated that the structural evolution and morphological changes of the milled alloys were sensitive to their Zirconium (at. \%) content. The morphological characterization showed that the crystallite size and the particle size decreased with increasing Zr content (at. \%). As well, as the Zr was added to the Ti-25NbXZr system, there was a clear decrease in the Vickers hardness and young's modulus. On the other hand, the coefficient of friction and wear rates were found to be decreasing with increasing Zr content.}, language = {en} } @misc{KhalilFellahHeziletal., author = {Khalil, S. and Fellah, Mamoun and Hezil, Naouel and Smata, L. and Montagne, Alex and Mejias, Alberto and Kossman, Stephania and Iost, Alain and Obrosov, Aleksei and Weiß, Sabine}, title = {Synth{\`e}se et caract{\´e}risation structurale d'un compos{\´e} nanostructur{\´e} de Ti, Mo et Zr pour applications biom{\´e}dicales}, series = {3rd International Conference on Mechanics and Materials : ICMM'2019 11-12 November 2019. Setif, Algeria, Abstracts book}, journal = {3rd International Conference on Mechanics and Materials : ICMM'2019 11-12 November 2019. Setif, Algeria, Abstracts book}, address = {Setif, Algeria}, pages = {243 -- 244}, abstract = {Le milieu m{\´e}dical est un perp{\´e}tuel demandeur de biomat{\´e}riaux compatibles surtout en orthop{\´e}die. Effectivement le nombre important d'arthroplasties effectu{\´e}es chaque ann{\´e}e ne cesse d'augmenter dans le monde, non seulement du fait vieillissement de la population ({\`a} partir de 65 ans), mais aussi de demandes de patients plus jeunes entre 45 ans et 55 ans. Actuellement, les compos{\´e}s {\`a} base de titane Ti sont largement utilis{\´e}s comme des biomat{\´e}riaux pour leur biocompatibilit{\´e}, leur r{\´e}sistance {\`a} la corrosion et leur faible module d'{\´e}lasticit{\´e}. Le molybd{\`e}ne et le zirconium sont parmi les meilleurs {\´e}l{\´e}ments alli{\´e}s parce qu'ils sont non toxiques et non allergiques et offrent d'excellentes propri{\´e}t{\´e}s. De plus,Le Zr peut augmenter la trempabilit{\´e} et la r{\´e}sistance {\`a} la corrosion de l'alliage . Mo est un {\´e}l{\´e}ment fort stabilisant pour la phase des alliages de titane et les alliages {\`a} base de Ti-Mo pr{\´e}sentent des propri{\´e}t{\´e}s m{\´e}caniques ad{\´e}quates compatibilit{\´e} et bonne cyto-compatibilit{\´e} . Par cons{\´e}quent, le syst{\`e}me Ti-Mo-Zr, qui a montr{\´e} une bonnes performances et de magnifiques perspectives dans l'application de biomat{\´e}riaux, a {\´e}t{\´e} intensivement{\´e}tudi{\´e} [1,2,3]. Cependant, les alliages de Ti largement utilis{\´e}s, tels que les interstitiels extra-low (ELI) Ti-6Al-4V (wt.\% en poids ), Ti- 5Al-2,5 Fe et Ti-6Al-7Nb, ont le risque de lib{\´e}rer de l'aluminium toxique (Al) et les Ions de vanadium (V) in vivo, ce qui peut causer des probl{\`e}mes de sant{\´e}, comme la maladie d'Alzheimer et la neuropathie[4].La m{\´e}tallurgie des poudres (MP), y compris la m{\´e}thode de mixture des composants en poudre, qui consiste {\`a} fritter titane en poudre ou ses m{\´e}langes avec d'autres composants en poudre, est un proc{\´e}d{\´e} {\´e}conomique {\`a} moindre cout. La nanotechnologie est intervenue dans la structuration des biomat{\´e}riaux {\`a} l'{\´e}chelle nanom{\´e}trique (entre1nmet 100 nm) par soucis d'am{\´e}lioration des propri{\´e}t{\´e}s m{\´e}canique surtout le module de Young.}, language = {fr} } @misc{MarchenkoYasenchukGuntheretal., author = {Marchenko, Ekaterina and Yasenchuk, Yuri and Gunther, Sergey and Baigonakova, Gulsharat and Gunther, Victor and Chekalkin, Timofey and Weiß, Sabine and Obrosov, Aleksei and Dubovikov, Kirill}, title = {Structural-phase surface composition of porous TiNi produced by SHS}, series = {Materials Research Express}, volume = {6}, journal = {Materials Research Express}, number = {11}, issn = {2053-1591}, doi = {10.1088/2053-1591/ab4e32}, pages = {12}, abstract = {The study aimed to characterize the structural-phase composition of the porous SHS TiNi surface explored by the GIXRD method. The surface layers at a depth of up to 100 nm mainly consist of amorphous nanocrystalline intermetallic oxycarbonitrides Ti₄Ni₂(O,N,C) with nonmetallic inclusions of different structural variants and routes of origin. Fine-porous alloys were synthesized at ignition temperatures of 450-480 °C. A distinct feature of the surface of crystalline phases therein was shown to be a low degree of crystallinity (up to 40\%) and presence of multifarious glass and cermet phases evident as NiSi₂, NaAlSiO (SO₄), SiO₂, MgSi₂, and CaCO₃. Conversely, large-pore alloys ignited at temperatures of 280-330 °C have a higher degree of crystallinity (up to 70\%). An individually selected GIXRD technique and precision structural phase analysis are capable to determine a set of other superficial nonmetallic and cermet phases reported as CaTiO₃, Si (P2O₇), CaSiO₃, MgAl₂O₄, TiNiAl, as well as the Ti₃SiC₂MAX phase.}, language = {en} } @misc{HezilFellahDjellabietal., author = {Hezil, Naouel and Fellah, Mamoun and Djellabi, Ridha and Touhami, Mohamed Zine and Montagne, Alex and Bouaksa, Fethia and Iost, Alain and Mejias, Alberto and Obrosov, Aleksei}, title = {Assessment of the Hydrophilic-Hydrophobic Balance of Alumina Oxidized at Different Temperatures via H₂O and C₄H₁₀ Vapor Adsorption}, series = {Defect and Diffusion Forum}, volume = {397}, journal = {Defect and Diffusion Forum}, issn = {1662-9507}, doi = {10.4028/www.scientific.net/DDF.397.161}, pages = {161 -- 168}, abstract = {The hydrophilic-hydrophobic surface area of alumina powder (Al₂O₃) oxidized at different temperatures was determined on the base of adsorption of water and butane vapor at 25°C. In the order to study the influence of thermal oxidation upon hydrophilic/hydrophobic character of the surface, samples of Al₂O₃ were characterized using granulometry, SEM and BET surface area measurement. SEM results showed that the thermal treatment does not affect the morphology of the Alunima. However, the increase of treatment temperature from 250 to 900°C results in changing of the hydrophilic-hydrophobic balance of Al₂O₃ surface.}, language = {en} } @misc{ObrosovSidelev, author = {Obrosov, Aleksei and Sidelev, Dmitry}, title = {Magnetron Sputtering System for High-rate Deposition of Al Thin Films}, abstract = {The study reports on technological possibilities of magnetron sputtering systems to high-rate deposition of aluminum films and its structure. There is shown the comparison of deposition rates of magnetron sputtering systems with direct current (DC), middle-frequency (MF) and high power pulsed (HiPIMS) supplies. This article presents the using of the combination of middle-frequency (MF) and high impulse power (HiPIMS) supply is a way to significant increase of deposition rates of Al films. The composition of discharge plasma in dependence of parameters of pulse is considered by optical emission spectroscopy. XRD survey shows the role of deposition mode on crystal structure and grain size of Al films. It can be interested to thermal-control and radio-technical coatings.}, language = {en} } @misc{FellahHezilSamadetal., author = {Fellah, Mamoun and Hezil, Naouel and Samad, Mohammed Abdul and Touhami, Mohamed Zine and Montagne, Alex and Iost, Alain and Obrosov, Aleksei and Weiß, Sabine}, title = {Preliminary investigation on the bio-tribocorrosion behavior of porous nanostructured β-type titanium based biomedical alloys}, series = {Materials Letters}, volume = {257}, journal = {Materials Letters}, issn = {0167-577X}, doi = {10.1016/j.matlet.2019.126755}, pages = {4}, abstract = {The bio-tribocorrosion behavior of newly developed near β-types Ti-15Nb and Ti-15Mo alloys was investigated in Phosphate-Buffered Saline (PBS) under different loads. Open-Circuit Potential (OCP), friction coefficient, wear volume and wear rate were evaluated. The results revealed that Ti-15Nb alloy exhibited lower wear rate, lower friction coefficient and better corrosion resistance during tribocorrosion than the Ti-15Mo alloy. This can be attributed to the diffusion of Nb which increases the repassivation rate (formation of a protective layer) in the Ti-15Nb alloy. In contrast Ti-15Mo shows a significantly higher rate of chemical reaction.}, language = {en} } @misc{GoncharovMasayloOrlovetal., author = {Goncharov, I. S. and Masaylo, Dmitriy V. and Orlov, Alexey and Razumov, Nikolay G. and Obrosov, Aleksei}, title = {The Effect of Laser Power on the Microstructure of the Nb-Si Based In Situ Composite, Fabricated by Laser Metal Deposition}, series = {Key Engineering Materials}, volume = {822}, journal = {Key Engineering Materials}, issn = {1662-9795}, doi = {10.4028/www.scientific.net/KEM.822.556}, pages = {556 -- 562}, abstract = {The Nb-Si in-situ composite samples were fabricated by laser metal deposition additive manufacturing technology from mechanically alloyed powders in vario-planetary ball mill. A laser metal of samples was carried out at various laser powers: 500 W, 1000 W, 1400 W. The microstructure of a sample grown at a laser power of 500 W consists of a solid solution of Nb, Nb3Si, and dendritic chains of Ti. When the laser power is increased to 1000 W, the volume fraction of silicides increases, the structural heterogeneity decreases. With further increase in laser power to 1400 W, Ti dissolves in Nb, dendritic chains disappear, Nb5Si3 silicide stabilizes.}, language = {en} } @misc{FellahHezilTouhamietal., author = {Fellah, Mamoun and Hezil, Naouel and Touhami, Mohamed Zine and Obrosov, Aleksei and Weiß, Sabine and Kashkarov, Egor B. and Lider, Andrey M. and Montagne, Alex and Iost, Alain}, title = {Enhanced Structural and Tribological Performance of Nanostructured Ti-15Nb Alloy for Biomedical Applications}, series = {Results in Physics}, volume = {15}, journal = {Results in Physics}, issn = {2211-3797}, doi = {10.1016/j.rinp.2019.102767}, pages = {7}, abstract = {Low modulus β-type Ti-15Nb alloys were prepared by subjecting them to different sintering temperatures (800, 900, 1000 and 1100 °C) and their morphological and structural properties were evaluated. X-ray diffraction analysis was used for the morphological characterization which indicated that the mean pore and crystallite size continuously decreased with increasing sintering temperature to reach the lowest values of 41 nm and 27.5 nm at 1100 °C, respectively. Moreover, the higher sintering temperature resulted in higher relative density, greater hardness and young's modulus of the Ti-15Nb alloys. Wear tests were conducted using a ball-on-plate type Oscillating tribometer, under different applied loads (2, 8 and 16 N) to evaluate their tribological characterization. The wear rate and friction coefficient were lower at higher sintering temperature. This enhancement in tribological properties was attributed to a grain refinement. The Ti-15Nb alloys sintered at 1100 °C showed the best tribological performance.}, language = {en} } @incollection{FellahHezilAbderrahimetal., author = {Fellah, Mamoun and Hezil, Naouel and Abderrahim, Karima and Samad, Mohammed Abdul and Montagne, Alex and Mejias, Alberto and Iost, Alain and Kossman, Stephania and Chekalkin, Timofey and Obrosov, Aleksei and Weiß, Sabine}, title = {Investigating the Effect of Sintering Temperature on Structural and Tribological Properties of a Nanostructured Ti-20Nb-13Zr Alloy for Biomedical Applications}, series = {Characterization of Minerals, Metals, and Materials}, booktitle = {Characterization of Minerals, Metals, and Materials}, publisher = {Springer}, address = {Cham}, isbn = {978-3-030-36628-5}, issn = {2367-1181}, doi = {10.1007/978-3-030-36628-5_61}, pages = {619 -- 629}, abstract = {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.}, language = {en} } @misc{FellahHezilTouhamietal., author = {Fellah, Mamoun and Hezil, Naouel and Touhami, Mohamed Zine and Hussien, Mohammed A. and Montagne, Alex and Mejias, Alberto and Iost, Alain and Kossman, Stephania and Chekalkin, Timofey and Obrosov, Aleksei and Weiß, Sabine}, title = {Effect of Sintering Temperature on Mechanical and Tribological Behavior of Ti-Ni Alloy for Biomedical Applications}, series = {TMS 2020 149th Annual Meeting \& Exhibition Supplemental Proceedings}, journal = {TMS 2020 149th Annual Meeting \& Exhibition Supplemental Proceedings}, publisher = {Springer}, address = {Cham}, isbn = {978-3-030-36295-9}, issn = {2367-1181}, doi = {10.1007/978-3-030-36296-6_157}, pages = {1701 -- 1710}, abstract = {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.}, language = {en} } @misc{HezilFellahMontagneetal., author = {Hezil, Naouel and Fellah, Mamoun and Montagne, Alex and Iost, Alain and Obrosov, Aleksei and Weiß, Sabine}, title = {Removal of Chromium (VI) from Water onto Activated Carbon by Adsorption in Dynamic Mode}, series = {TMS 2020 149th Annual Meeting \& Exhibition Supplemental Proceedings}, journal = {TMS 2020 149th Annual Meeting \& Exhibition Supplemental Proceedings}, publisher = {Springer}, address = {Cham}, isbn = {978-3-030-36295-9}, issn = {2367-1181}, doi = {https://doi.org/10.1007/978-3-030-36296-6_80}, pages = {855 -- 863}, abstract = {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.}, language = {en} } @misc{EvdokimovDoynovOssenbrinketal., author = {Evdokimov, Anton and Doynov, Nikolay and Ossenbrink, Ralf and Obrosov, Aleksei and Weiß, Sabine and Michailov, Vesselin}, title = {Thermomechanical laser welding simulation of dissimilar steel-aluminum overlap joints}, series = {International Journal of Mechanical Sciences}, volume = {190}, journal = {International Journal of Mechanical Sciences}, issn = {1879-2162}, doi = {10.1016/j.ijmecsci.2020.106019}, pages = {18}, abstract = {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.}, language = {en} } @misc{FellahHezilTouhamietal., author = {Fellah, Mamoun and Hezil, Naouel and Touhami, Mohamed Zine and Samad, Mohammed Abdul and Obrosov, Aleksei and Bokov, Dmitry O. and Marchenko, Ekaterina and Montagne, Alex and Iost, Alain and Alhussein, Akram}, title = {Structural, tribological and antibacterial properties of (α + β) based ti-alloys for biomedical applications}, series = {Journal of Materials Research and Technology}, volume = {9}, journal = {Journal of Materials Research and Technology}, number = {6}, issn = {2238-7854}, doi = {10.1016/j.jmrt.2020.09.118}, pages = {14061 -- 14074}, abstract = {Implant-related follow up complications resulting from poor implant integration, delamination, chipping, mechanical instability, inflammation or graft-vs-host reaction may lead to low patient tolerance, prolonged care and sometimes leading to a second surgery. Hence, there is an urgent need for developing biomaterials which will help to overcome the above compatibility problems. Ti based alloys have been widely used for biomedical applications, due to their excellent properties, such as low modulus, high biocompatibility and high corrosion resistance. In order to further improve the physical, mechanical and tribological properties of these alloys, microstructural modification is often required. Hence, this study aims to develop and evaluate the structural and tribological behavior of Hot Isostatic Pressed (HIPed) and sintered Ti-6Al-7Nb samples containing niobium, which is less toxic and less expensive as compared to the usual alloying element, vanadium (Ti-6Al-4 V). The Ti-6Al-7Nb alloys were fabricated by using nanoparticle powders milled for different durations (2, 6, 12 and 18 h) to evaluate the effect of milling time on the morphological and structural properties. Friction and wear tests were carried out on the (HIPed) and finally sintered Ti-6Al-7Nb alloy samples, to evaluate their tribological properties under different applied loads (2, 8 and 16 N), with an alumina α-Al2O3 ball as a counter face using an oscillating tribometer. The physical characterization of the nanopowders formed using different milling times indicated that the particle and crystallite size continually decreased with increasing milling time, while the microstrain increased. It is observed that the friction coefficient and wear rate for the samples prepared by powders milled for 18 h and tested under 2 N were lowest with values of 0.25 and 1.51 × 10-2 μm3∙N-1 μm-1, respectively compared to other milled samples. This improvement in tribological properties is attributed to the grain refinement at high milling times. The antibacterial evaluation of the fabricated alloys showed an improvement in antibacterial performance of the samples milled at 18 h compared to the other milling times.}, language = {en} } @misc{BaigonakovaMarchenkoChekalkinetal., author = {Baigonakova, Gulsharat and Marchenko, Ekaterina and Chekalkin, Timofey and Kang, Ji-hoon and Weiß, Sabine and Obrosov, Aleksei}, title = {Influence of Silver Addition on Structure, Martensite Transformations and Mechanical Properties of TiNi-Ag Alloy Wires for Biomedical Application}, series = {Materials}, volume = {13}, journal = {Materials}, number = {21}, issn = {1996-1944}, doi = {10.3390/ma13214721}, pages = {11}, abstract = {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.}, language = {en} } @misc{SaoudiFellahHeziletal., author = {Saoudi, Adel and Fellah, Mamoun and Hezil, Naouel and Lerari, Djahida and Khamouli, Farida and Atoui, L'hadi and Bachari, Khaldoun and Morozova, Iuliia and Obrosov, Aleksei and Samad, Mohammed Abdul}, title = {Prediction of mechanical properties of welded steel X70 pipeline using neural network modelling}, series = {International Journal of Pressure Vessels and Piping}, volume = {186}, journal = {International Journal of Pressure Vessels and Piping}, issn = {0308-0161}, doi = {10.1016/j.ijpvp.2020.104153}, pages = {8}, abstract = {An artificial neural network (ANN) model was developed to predict tensile and impact properties of a submerged arc helical welded (SAHW) pipeline steel API X70 based upon its chemical composition. Weight percent of the elements was considered as the input, while the tensile and Charpy impact properties were considered as the outputs. Scatter diagrams and two statistical parameters (absolute fraction of variance and relative error) were used to evaluate the prediction performance of the developed artificial neural network model. The predicted values were found to be in excellent agreement with the experimental data and the current model has a good learning precision and generalization (for training, validation and testing data sets). The results revealed that the developed model is very accurate and has a strong potential for capturing the interaction between the mechanical properties and chemical composition of welded high strength low alloy (HSLA) steels.}, language = {en} } @misc{FellahHezilGuerfietal., author = {Fellah, Mamoun and Hezil, Naouel and Guerfi, Kamel and Djellabi, Ridha and Montagne, Alex and Iost, Alain and Borodin, Kirill and Obrosov, Aleksei}, title = {Mechanistic pathways of cationic and anionic surfactants sorption by kaolinite in water}, series = {Environmental Science and Pollution Research}, volume = {28}, journal = {Environmental Science and Pollution Research}, number = {6}, issn = {1614-7499}, doi = {10.1007/s11356-020-11083-6}, pages = {7307 -- 7321}, abstract = {Surfactants are widely used in many chemical industries and as primary components of cleaning detergents due to their specific characteristics, which in turn results in high pollution of domestic and industrial wastewaters by such substances. In this study, the mechanistic pathways of the adsorption of cationic benzyl-dimethyl-dodecyl ammonium bromide (BDDAB) and anionic sodium dodecyl sulfate (SDS) surfactants on kaolinite clay in water were investigated. The results showed that the adsorption of anionic surfactant (SDS) on kaolinite is better compared with cationic surfactant (BDDAB), wherein the ♦maximum adsorption capacity was found 161.4 μmol g-1 and 234 μmol g-1 for BDDAB and SDS, respectively. Adsorption kinetics were the best suited to pseudo-second-order model for both BDDAB and SDS with an adsorption rate constant of 0.028 g μmol-1 min-1 and 0.023 g μmol-1 min-1, respectively. Meanwhile, the adsorption of BDDAB by kaolinite showed that the isotherm adsorption tended to follow the Langmuir-Freundlich and Freundlich isotherm models. However, the SDS adsorption isotherm obeyed only the Langmuir-Freundlich model.}, language = {en} } @misc{KokorevChekalkinMarchenkoetal., author = {Kokorev, Oleg and Chekalkin, Timofey and Marchenko, Ekaterina and Yasenchuk, Yuri and Gunther, Sergey and Serebrov, Vladimir and Chernyshova, Alena and Obrosov, Aleksei and Kang, Ji-hoon}, title = {Exploring the role of surface modifications of TiNi-based alloys in evaluating in vitro cytocompatibility: a comparative study}, series = {Surface Topography: Metrology and Properties}, volume = {8}, journal = {Surface Topography: Metrology and Properties}, number = {4}, issn = {2051-672X}, doi = {10.1088/2051-672X/abc0f9}, pages = {14}, abstract = {The aim of this study was the comparative analysis of in vitro bio-testing of solid and porous TiNi samples with modified surfaces (intact, oxidated, and etched). Tests for cytocompatibility, hemolysis, and cytotoxicity (MTT) as well as visualization by confocal and scanning electron microscopy have shown that the chemically modified samples are the most cytocompatible. The intact and etched samples did not induce hemolysis greater than 2\%, and thus they comply with the ISO 10993-4:2018 standard for hemolysis by blood-contacting biomaterials. Direct culture of etched samples with MCF-7 cells and human leukocytes showed low cytotoxicity. At the same time, the cytotoxicity of samples oxidated at 500 °C was significantly greater than that of the etched samples. Confocal and electron microscopy also confirmed the abovementioned quantitative data. The cells attached to the etched surface in numbers sufficient for them to be able to grow and proliferate on this substrate in vitro. These findings indicate that solid and porous TiNi alloy with surface modifications achieved by a cost-effective method is biotolerable and promising for clinical use and for tissue engineering.}, language = {en} } @misc{YasenchukMarchenkoBaigonakovaetal., author = {Yasenchuk, Yuri and Marchenko, Ekaterina and Baigonakova, Gulsharat and Gunther, Sergey and Kokorev, Oleg and Gunther, Victor and Chekalkin, Timofey and Topolnitskiy, Evgeniy and Obrosov, Aleksei and Kang, Ji-hoon}, title = {Study on tensile, bending, fatigue, and in-vivo behavior of porous SHS-TiNi alloy used as a bone substitute}, series = {Biomedical Materials}, volume = {16}, journal = {Biomedical Materials}, number = {2}, issn = {1748-605X}, doi = {10.1088/1748-605X/aba327}, pages = {14}, abstract = {Intermetallic porous SHS-TiNi alloys exhibit tangled and specific stress-strain characteristics. The article aims to evaluate the findings emanated from experiments using standard and proprietary instruments. Fatigue testing under repeated complex loading was used to measure the total number of load cycles to failure of SHS-TiNi samples. 70\% of the tested samples, passed through 106 cycles without failure due to the reversible martensite transformation in the TiNi phase, one of the prevailing constituents of a multiphase matrix. The fractured surfaces were analyzed using SEM and confocal laser scanning instruments. Microscopic studies showed that the entire surface of the sample is concealed with the miscellaneous strata resulted from the SHS process, which effectively protect the porous alloy in a corrosive environment. Numerous non-metallic inclusions, which are also attributed to the SHS reaction, do not have a significant impact on the deformation behavior and fatigue performance. In this context, the successful in vivo functioning of porous grafts assessed in a canine rib-plasty model allows the bone substitute to be congruentially deformed in the body without rejection and degradation, having a long operational life, often greater than 17 million cycles. It acknowledges the potential benefits of SHS-TiNi as a superior osteoplastic material and its high resistance to corrosion fatigue.}, language = {en} } @misc{HazilFellahMontagneetal., author = {Hazil, Naouel and Fellah, Mamoun and Montagne, Alex and Iost, Alain and Obrosov, Aleksei and Weiß, Sabine}, title = {Study of the photocatalytic degradation of Orange methyl dye in the presence of titanium dioxide}, series = {La Troisi{\`e}me Conf{\´e}rence M{\´e}diterran{\´e}enne de la Biodiversit{\´e} 2019 (BIODIV 2019)}, journal = {La Troisi{\`e}me Conf{\´e}rence M{\´e}diterran{\´e}enne de la Biodiversit{\´e} 2019 (BIODIV 2019)}, publisher = {L'ASCOB-SYRTIS}, address = {Hammamet, Tunisie}, pages = {105}, abstract = {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\%.}, language = {en} } @misc{MorozovaObrosovNaumovetal., author = {Morozova, Iuliia and Obrosov, Aleksei and Naumov, Anton and Kr{\´o}licka, Aleksandra and Golubev, Iurii and Bokov, Dmitry O. and Doynov, Nikolay and Weiß, Sabine and Michailov, Vesselin}, title = {Impact of Impulses on Microstructural Evolution and Mechanical Performance of Al-Mg-Si Alloy Joined by Impulse Friction Stir Welding}, series = {Materials}, volume = {14}, journal = {Materials}, number = {2}, issn = {1996-1944}, doi = {https://doi.org/10.3390/ma14020347}, abstract = {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.}, language = {en} } @misc{BiedunkiewiczFigielGarbiecetal., author = {Biedunkiewicz, Anna and Figiel, Paweł and Garbiec, Dariusz and Obrosov, Aleksei and Pawlyta, Mirosława and Biedunkiewicz, Witold and Pruss, Przemysław and Rokosz, Krzysztof and Wr{\´o}bel, Rafał and Raaen, Steinar and Weiß, Sabine and Bokov, Dmitry O.}, title = {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}, series = {Materials}, volume = {14}, journal = {Materials}, number = {1}, issn = {1996-1944}, doi = {https://doi.org/10.3390/ma14010231}, abstract = {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.}, language = {en} } @misc{MarchenkoBaigonakovaDubovikovetal., author = {Marchenko, Ekaterina and Baigonakova, Gulsharat and Dubovikov, Kirill and Yasenchuk, Yuri and Chekalkin, Timofey and Obrosov, Aleksei}, title = {Comparative study on the high-temperature oxidation resistance of porous and solid TiNi-based alloys}, series = {Surface Topography: Metrology and Properties}, volume = {9}, journal = {Surface Topography: Metrology and Properties}, number = {2}, issn = {2051-672X}, doi = {https://doi.org/10.1088/2051-672X/abf324}, abstract = {The present work aims to characterize the surface features of solid and porous (sintered and SHS) TiNi-based alloys subjected to oxidation at 1000 °C in static air in the context of their resistance to high-temperature atmospheric attack. Clear differences between the intact and oxidated surfaces indicate the complexity of a chemicothermal diffusion process evolving therein. Microscopic and XRD studies showed that the dominant superficial constituent in all oxidated samples is titanium dioxide in the rutile modification. The phase and structural properties of the surface layers suggest that porous sintered and solid alloys are most susceptible to high-temperature corrosion due to bare reactive surfaces, which negatively affects their overall biocompatibility. Surface morphology analysis revealed microporous and loose superficial layers having a thickness of 8-10 and 50-60 μm, respectively in the solid and sintered alloy. Also, these alloys showed a high content of leaching NiO and free Ni within the surface layer. Conversely, a thin (0.5-0.6 μm), dense, and multifarious layer of oxycarbonitrides Ti4Ni2(O,N,C) concealing the porous SHS-TiNi matrix inhibits the negative effect of high-temperature oxidation.}, language = {en} } @misc{FouziaFellahHeziletal., author = {Fouzia, Hammadi and Fellah, Mamoun and Hezil, Naouel and Aissani, Linda and Mimanne, Goussem and Mechachti, Said and Samad, Mohammed Abdul and Montagne, Alex and Iost, Alain and Weiß, Sabine and Obrosov, Aleksei}, title = {The effect of milling time on the microstructure and mechanical properties of Ti-6Al-4Fe alloys}, series = {Materials Today Communications}, volume = {27}, journal = {Materials Today Communications}, issn = {2352-4928}, doi = {10.1016/j.mtcomm.2021.102428}, pages = {11}, abstract = {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.}, language = {en} } @misc{GrudininSidelevBleykheretal., author = {Grudinin, V. A. and Sidelev, D. V. and Bleykher, G. A. and Yuriev, Yu N. and Krivobokov, V. P. and Berlin, E. V. and Grigoriev, V. Yu and Obrosov, Aleksei and Weiß, Sabine}, title = {Hot target magnetron sputtering enhanced by RF-ICP source for CrNx coatings deposition}, series = {Vacuum}, volume = {191}, journal = {Vacuum}, issn = {0042-207X}, doi = {10.1016/j.vacuum.2021.110400}, pages = {9}, abstract = {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.}, language = {en} } @misc{KrzywińskiSadowskiStefaniuketal., author = {Krzywiński, Kamil and Sadowski, Łukasz and Stefaniuk, Damian and Obrosov, Aleksei and Weiß, Sabine}, title = {Engineering and Manufacturing Technology of Green Epoxy Resin Coatings Modified with Recycled Fine Aggregates}, series = {International Journal of Precision Engineering and Manufacturing-Green Technology}, volume = {9}, journal = {International Journal of Precision Engineering and Manufacturing-Green Technology}, number = {1}, issn = {2198-0810}, doi = {10.1007/s40684-021-00377-w}, pages = {253 -- 271}, abstract = {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.}, language = {en} }