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Konakov V.G.,Saint Petersburg State University | Archakov I.Y.,Russian Academy of Sciences | Solovieva E.N.,Scientific and Technical Center Glass and Ceramics | Golubev S.N.,Scientific and Technical Center Glass and Ceramics | Orlov A.V.,Polytechnic University of Mozambique
Materials Physics and Mechanics | Year: 2017

For the first time in science of metal-matrix composite materials, "Gum-metalgraphene" nanocomposite is synthesized which has a Gum metal (Ti-Nb-Ta-Zr-O alloy) matrix containing graphene nanoinclusions. To do so, we created a novel method to synthesize Gum metal and "Gum-metal-graphene" nanocomposite. In the latter case, micromechanical splitting of thermo-exfoliated graphite is used as graphene source. With Xray analysis, we demonstrated that the phase compositions of Gum metal specimens and the nanocomposite matrix are identical to one of typical Gum metal compositions reported in literature. © 2017, Peter the Great St. Petersburg Polytechnic University.


Konakov V.G.,Saint Petersburg State University | Arutyunyan A.R.,Saint Petersburg State University | Lomakin I.V.,Saint Petersburg State University | Solovieva E.N.,Scientific and Technical Center Glass and ceramics | And 4 more authors.
Materials Physics and Mechanics | Year: 2017

In this paper, we present experimental data on synthesis and investigation of the mechanical properties of bulk nickel and bulk "nickel - 8 mol.% Y2O3-92 mol.% ZrO2" nanocomposite with a nickel matrix containing crystalline ceramic nanoparticles. In terms of wt.%, this nanocomposite (hereinafter called Ni-YSZ nanocomposite) contains 1 wt.% of ceramic nanoparticles. The Ni and Ni-YSZ nanocomposite specimens were fabricated by powder metallurgy technique with successive annealing at 1250 °C. In tension and compression tests, we revealed stress-strain dependences showing degradation of strength and ductility exhibited by Ni-YSZ nanocomposite, as compared to those of pure Ni fabricated in the same conditions. The fatigue tests of the specimens were performed in the symmetric tensioncompression regime based on 107 cycles. The fatigue limits were identified. The specimen fabricated from pure Ni powder showed the fatigue limit of 110 MPa, whereas Ni-YSZ composite exhibited the fatigue limit of 50 MPa. Thus, the insertion of ceramic nanoparticles into Ni matrix gives rise to more than two times decrease of the fatigue limit, as compared to pure Ni. The fractography of fatigue fracture surfaces was examined by scanning electron microscopy. In both materials tested, three stages of the fatigue crack distribution are observed which are the crack initiation, stable crack growth and unstable crack growth stages. Both materials contain the significant amounts of pores, and pore merging is observed at the unstable crack growth stage. © 2017, Peter the Great St. Petersburg Polytechnic University.


Konakov V.G.,Saint Petersburg State University | Golubev S.N.,Scientific and Technical Center Glass and Ceramics | Solovyeva E.N.,Institute of Problems of Mechanical Engineering | Archakov I.Y.,Institute of Problems of Mechanical Engineering | And 2 more authors.
Materials Physics and Mechanics | Year: 2012

Precursor powders with controlled average agglomerate size in the range of 40-12000 nm were synthesized using the reverse precipitation sol-gel. The correlation between the agglomerate size and mechanical strength of the final ceramics synthesized from these precursor powders and the content of Ce 3+ and Ce 4+ in the precursors was studied using BET, XRD, TEM, PSD, and DSC methods. © 2012, Institute of Problems of Mechanical Engineering.


Konakov V.G.,Saint Petersburg State University | Solovyeva E.N.,Russian Academy of Sciences | Archakov I.Yu.,Russian Academy of Sciences | Golubev S.N.,Scientific and Technical Center Glass and Ceramics
Reviews on Advanced Materials Science | Year: 2013

Thermal analysis of ternary Al-BN-SiC batch aimed for the production of nanomodified functional Al2O3-BN-SiC ceramics and the analysis of binary systems and individual compounds forming the above system were performed. It was shown that powders dispersion and samples pretreatment (pressing, heating in air, and vacuum annealing) affect thermal behavior of the samples. The nature of endothermic and exothermic effects as well as peculiarities of weight changes during heating-cooling cycles are discussed. The information for ternary system samples is compared with the data obtained for samples modified by nano-sized zirconia powder. As a result of the study, the conclusion on the suitability of the chosen composition for themanufacturing of nanomodified functional ceramics is stated. © 2013 Advanced Study Center Co. Ltd.


Konakov V.G.,Saint Petersburg State University | Golubev S.N.,Scientific and Technical Center Glass and Ceramics | Solovyeva E.N.,Institute of Problems of Mechanical Engineering | Archakov I.Yu.,Institute of Problems of Mechanical Engineering | And 2 more authors.
Materials Physics and Mechanics | Year: 2011

Precursor powders with the final 9C22O3-91ZrO 2 (mol.%) composition were synthesized using the reverse precipitation sol-gel method varying the concentrations of the solutions of the initial salt reagents. A set of physical and chemical investigation approaches shows that the mechanical strength of Ce-Zr ceramics depends both on precursor dispersity and on CeO2 content. © 2011, Institute of Problems of Mechanical Engineering.


Konakov V.G.,Saint Petersburg State University | Solovyeva E.N.,Russian Academy of Sciences | Archakov I.Yu.,Saint Petersburg State University | Golubev S.N.,Scientific and Technical Center Glass and Ceramics
Materials Physics and Mechanics | Year: 2013

This paper reports the development of a sturdy reactive-linked ceramics based on Al2O3(Al)-SiC-BN-Si3N4 system. Ceramic samples of different initial compositions and varied manufacturing procedure were studied by XRD; mechanical strength of these samples is discussed. It is stated that such products of chemical interactions occurring during ceramics production, as Si and AlN positively affects ceramics strength. The effect of aluminum, aluminum borates, and silicon nitride content on the strength of final ceramics is discussed. © 2013, Institute of Problems of Mechanical Engineering.


Konakov V.G.,Saint Petersburg State Polytechnic University | Kurapova O.Yu.,Saint Petersburg State Polytechnic University | Novik N.N.,Saint Petersburg State Polytechnic University | Golubev S.N.,Scientific and Technical Center Glass and Ceramics | And 5 more authors.
Reviews on Advanced Materials Science | Year: 2014

Optimized approach for nanotwinned copper synthesis via electrodeposition technique is described. SEM, EBSD, XRD, and Nanoindentation tests of the synthesized layers were performed. The results of the tests demonstrate good surface quality and improved hardness. © 2014 Advanced Study Center Co. Ltd.

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