Sofiya Aydinyan

Sofiya Aydinyan

PhD
Researcher

About

50
Publications
7,505
Reads
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361
Citations
Citations since 2017
38 Research Items
289 Citations
2017201820192020202120222023020406080
2017201820192020202120222023020406080
2017201820192020202120222023020406080
2017201820192020202120222023020406080
Education
September 2002 - November 2012

Publications

Publications (50)
Article
Self-lubricating coatings extend the efficient dry-operational life of cutting and forming tools. In the current work, millimeter-thick NiCrBSi coatings with 10 wt% metal sulfide i.e. Ni3S2, CuS, or Bi2S3 were fabricated on a stainless steel substrate by laser cladding (in-situ alloying). Thermodynamic modelling utilizing the calculation of phase d...
Article
It is a well-established fact, that the tribological performance of titanium and its alloys at high temperatures is poor, especially for self-mated titanium‑titanium pairs. Previous work has shown a significant improvement in mechanical and high temperature tribological behaviour (700–900 °C) for pure Ti sintered with TiB2 ceramic, occasioned by th...
Article
Full-text available
A novel pathway for the magnesiothermic reduction of boron oxide and magnesium dodecaboride (MgB12) in the presence of carbon by a self-propagating high-temperature synthesis method was proposed that was aimed at the direct preparation of boron carbide nanopowder. The combined utilization of two boron sources, boron oxide and MgB12, allowed tailori...
Article
Full-text available
The programmed reduction of tungstates and molybdates may yield the production of an intimate mixture of metals, pseudo-alloys or composite powders. As an extension of the study of obtaining powders of tungsten-copper, molybdenum-copper and tungsten-nickel from their respective salts, in the present study the reduction of silver tungstate was perfo...
Article
Single-phase, fine-grained high entropy MnFeCoNiCu alloy and (MnFeCoNiCu)3O4 oxide powders have been pioneered by in-situ solution combustion synthesis without post-treatment, utilizing alanine and glycine as organic reducers and ammonium nitrate as an auxiliary oxidizing agent. In order to regulate the porosity, homogeneity, phase composition and...
Article
Full-text available
The influence of mechano-ultrasonic activation (MUA) and nano-additives (carbon nanotubes-CNT) on the interaction pathway of nickel–aluminum powder mixture at high heating rates was investigated. The optimum conditions of the mechano-ultrasonic activation, along with the phase and structure formation peculiarities of nickel–aluminum and nickel–alum...
Article
Full-text available
This work reports on the spark plasma sintering (SPS) of self-propagating high-temperature-synthesis (SHS)-derived Ni-W and Ni-W-2wt%hBN (4:1 molar ratio of metals) powders. The synthesis was carried out from a mixture of NiO and WO3 using Mg + C combined reducers through a thermo-kinetic coupling approach. Experiments performed in the thermodynami...
Article
Full-text available
Modeling the self-sustained high-temperature synthesis (SHS) reaction via thermal dilution and transformation of the reaction heterogeneous media into a moderate exothermic one has unlimited potential for designing inorganic powders of a certain morphology beneficial for advanced consolidation. Thermal/inert dilution of the high-exothermic mixtures...
Article
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Understanding of the decisive role of non-isothermal treatment on the interaction mechanism and kinetics of the MoO3-CuO-Mg-C system is highly relevant for the elaboration of optimal conditions at obtaining Mo-Cu composite powder in the combustion processes. The reduction pathway of copper and molybdenum oxides with combined Mg + C reducing agents...
Article
Full-text available
The capability of self-propagating high-temperature synthesis (SHS) to produce powders that are characterized by a high sintering ability, owing to high heating and cooling rates inherent to the exothermic reaction, is of a special interest for the industry. In particular, SHS-derived powders comprise a significant defect concentration in order to...
Article
Full-text available
Functional features of Ni-W composite materials combined with successful performance enabled a breakthrough in their broad application. To disclose the formation pathway of Ni-W composite materials at extreme conditions of combustion synthesis in the NiO-WO3-Mg-C and NiWO4-Mg-C systems for the optimization of the synthesis procedure, the process wa...
Preprint
Full-text available
Understanding of the decisive role of the interaction mechanism and kinetics in the combustion processes is highly relevant for the elaboration of optimal conditions for obtaining Mo-Cu composite powders. From this perspective, the efficient delivery of the reduction mechanism of copper and molybdenum oxides with combined Mg + C reducing agents at...
Article
Full-text available
The challenge to develop new robust materials inspired the current research on a microwave synthesis and subsequent spark plasma sintering of a lightweight superhard B4C-27wt.%ReB2 ceramic composite. A strategy for fabricating high density parts was developed by sintering the microwave synthesized B4C-ReB2 composite without additives. The bulk mate...
Article
Advantages and industrial importance of C40 Mo(Si1-x,Alx)2 structure for technical applications have been widely proven. This work details Mo(Si1-x,Alx)2 composite preparation by reactive selective laser melting of (Mo + 2Si) + 30 wt%AlSi10Mg powder. During the process, Mo(Si1-x,Alx)2 (x = 0.33) nucleates and grows as the primary phase alongside in...
Article
Full-text available
Mo(Si1−x,Alx)2 composites were produced by a pulsed laser reactive selective laser melting of MoSi2 and 30 wt.% AlSi10Mg powder mixture. The parametric study, altering the laser power between 100 and 300 W and scan speed between 400 and 1500 mm·s −1 , has been conducted to estimate the effect of processing parameters on printed coupon samples' qual...
Article
Full-text available
The laser power bed fusion approach has been successfully employed to manufacture Mo(Si,Al)2-based composites through the selective laser melting of a MoSi2-30 wt.% AlSi10Mg mixture for high-temperature structural applications. Composites were manufactured by leveraging the in situ reaction of the components during printing at 150–300 W laser power...
Article
Selective laser melting was exploited to fabricate lattice structures from TiB2-Ti powder mixtures of high ceramic content (50wt.%TiB2). The lattice structures of 0.8 mm unit cell size were nitridized to produce TiB2-TiN ceramic-ceramic composite. During processing, TiB2 is partially transformed into TiB. Lattice structures of the TiB2-TiB-TiN comp...
Article
Full-text available
One of the main limitations for widespread additive manufacturing is availability and processability of the precursor materials feedstock. For the first time, this study reports the development of a “pomegranate-like” structured TiB2-Si ceramic-metalloid powder feedstock suitable for selective laser melting (SLM) of ceramic-based composite. The pow...
Article
An increasing need in customized ceramics and ceramic-metal composites has driven the development of powders feedstock and procedures for utilization of additive manufacturing for production of mechanically reliable composites. However, processing of materials with a high fraction of ceramic particles is still in its infancy. Herein we report on 3D...
Article
Full-text available
ZrC-TiC-MoSi 2 ceramic composite was consolidated by spark plasma sintering at 1850-1900°C temperature, for 5-10 min of dwell time under 50 MPa of applied pressure. The influence of MoSi2 addition on the mechanical performance and microstructure of ZrC-TiC composite was investigated. Compared with ZrC-TiC, the sinterability of ZrC-TiC-MoSi 2 was im...
Article
Full-text available
The reaction pathway for the joint reduction of nickel and tungsten oxides with the use of Mg/C combined reducer was studied by DTA/TG technique. It was revealed that reduction of the metal oxides is initiated with double-stage magnesiothermal reduction (reducing the nickel oxide, firstly, and tungsten oxide, secondly) at temperatures near the melt...
Article
Full-text available
Utilization of microwave-assisted (MW) synthesis and subsequent spark plasma sintering as an efficient and rapid synthetic route toward the preparation and consolidation of ultrahard B4C boron carbide without additives is reported. Magnesium dodecaboride (MgB12) and carbon were used as raw materials for stepwise MW synthesis of B4C at irradiation p...
Article
Full-text available
The catalytic effect of metal oxide/alumina whiskers (CeO 2 , Mn 3 O 4 , NiO, Co 3 O 4 , Fe 2 O 3 , Cr 2 O 3 /AW) was evaluated on their ability to drive the nitridation of silicon and to generate mesoporous fibrous silicon networks. Silicon powder with different particles size along with the catalyst was nitridized at 1300 °C for 5 h in nitrogen a...
Conference Paper
Full-text available
Zirconium carbide based materials were consolidated via spark plasma sintering and high-pressure high-temperature (HPHT) sintering methods. Fully dense ZrC-TiC compacts were produced by HTHP SPS technique at 1600-1700°C and were characterized by 370 GPa and 23.7 GPa values of Young’s modulus and Vickers microhardness, respectively. By the addition...
Conference Paper
Full-text available
Titanium has been evaluated in a broad range of aerospace, biomedical and sports equipment applications due to its unique combination of high mechanical strength, light weight and good biocompatibility. However, Ti implants are often subject to wear in specific areas. Therefore, the improvement of mechanical properties, such as hardness, wear resis...
Conference Paper
Full-text available
The concept of manufacturing of near-net-shaped three-dimensional ceramic-based parts with the required geometry is motivated by design and development of advanced ceramics for high-performance applications. It is an incontestable fact, that additive manufacturing (AM), as an intensively developing smart technology, owns a unique position in modern...
Article
Lattice structures, their shape, orientation, and density make the critical building blocks for macro-scale geometries during the AM process and, therefore, manipulation of the lattice structure extends to the overall quality of the final product. This work reports on manufacturing of MoSi 2 -Si 3 N 4 ceramic lattices through a selective laser melt...
Article
Full-text available
The in situ preparation of Mo–Cu from copper molybdate in the combustion mode with the help of thermo-kinetic coupling approach using the combined magnesium/carbon reducer to provide controllable thermal conditions is reported. To determine the optimum processing parameters, the stepwise nature of reaction mechanism in the CuMoO4–Mg–C system was co...
Article
Full-text available
A novel approach for the preparation of molybdenum carbide by solution combustion synthesis (SCS) combined with subsequent programmed heating of SCS products was proposed using ammonium heptamolybdate (AHM) and organic reducers (glycine, alanine, glucose, etc.) as precursors. It has been shown that SCS temperature and composition of the products ar...
Article
Full-text available
Thepossibilityofthemolybdenumoxide(MoO3)reductionbytheMg–Cmixturewasinvestigatedunder the self-sustaining combustion regime. Thermodynamic analyses for the MoO3–xMg–yC system were performed. Optimal ranges of x and y coefficients to ensure complete reduction of MoO3 to metallic molybdenum were found. The influence of x and y values on the process par...
Article
Additive manufacturing is gaining increasing attention as it provides cost-effective and waste-less production of materials with multi-axis geometries. Selective laser sintering of ceramics is very challenging in terms of poor sinterability caused by low thermal shock resistance and insufficient electron conductivity blocking absorption of laser be...
Article
Difficulties in sintering refractory ceramics limit their potential high-demanding applications. Selective laser sintering/melting of ceramics is extremely challenging due to poor sinterability of refractories caused by a low thermal shock resistance and an insufficient electron conductivity blocking absorption of laser electron beam energy, etc. H...
Article
W-Cu composite materials with various molar ratio of constituent metals (W:Cu = 2:1 and 1:3) were synthesized via co-reduction of WO3 and CuO oxides precursors with Mg + C combined reducer in the combustion mode by applying reaction's thermo-kinetic coupling approach. The interaction mechanism and phase and microstructure formation laws in the 2WO3...
Article
Full-text available
The mechanism of copper (II) oxide and molybdenum (VI) oxide co-reduction by Mg + C mixture was investigated at non-isothermal conditions by carrying out simultaneous differential thermal (DTA) and thermogravimetric (TG) analyses combined with X-ray diffraction (XRD) analysis of intermediate and final products. The whole process was found to involv...
Article
Full-text available
The mechanism of copper molybdate carbothermal reduction was investigated at non-isothermal conditions by carrying out simultaneous differential thermal (DTA) and thermal-gravimetric (TGA) analyses combined with X-ray diffraction (XRD) analysis of intermediate and final products. In order to understand the influence of copper molybdate preparation...
Article
The possibility of the molybdenum oxide (MoO3) reduction by the Mg–C mixture was investigated under the self-sustaining combustion regime. Thermodynamic analyses for the MoO3–xMg–yC system were performed. Optimal ranges of x and y coefficients to ensure complete reduction of MoO3 to metallic molybdenum were found. The influence of x and y values on...
Article
Novel porous NiZr-based potential biomaterials for orthopaedic application were developed using the combustion reaction in the Ni + Zr + additive mixtures. The effect of various additives (ZrH2, CaCO3, NH4F and Teflon) on the combustion behaviour in the low-caloric Ni + Zr mixtures was investigated. To obtain molten porous NiZr-based product Teflon...
Article
Full-text available
Novel porous NiZr-based potential biomaterials for orthopaedic application were developed using the combustion reaction in the Ni + Zr + additive mixtures. The effect of various additives (ZrH 2 , CaCO 3 , NH 4 F and Teflon) on the combustion behaviour in the low-caloric Ni + Zr mixtures was investigated. To obtain molten porous NiZr-based product...
Article
The possibilities of the synthesis of submicron MoSi2 and MoSi2–Si3N4 composite powders were investigated using inorganic salt-assisted combustion synthesis method. Combustion laws in the MoO3–3Mg–2Si–NaCl and Mo–5Si–NaCl–Si3N4–N2 systems were studied. The main factors influencing the combustion parameters, phase composition and microstructure of p...

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