Композиты и Наноструктуры                                       COMPOSITES and NANOSTRUCTURES

CONTENTS

A.L.Nebera, A.V.Lizunov, A.A.Semenov

NANOCRYSTALLINE TANTALUM POWDERS: PRODUCTION, PROPERTIES, APPLICATION PERSPECTIVES...................................121

Nanocrystalline tantalum powders of various specific surface produced by SC «VNIINM» technology were studied by transmission and scanning electron microscopy. The powders consist of the particles of linear dimension varying from 1 to 100 pm, they have a porous structure and are formed by crystallites. Crystalites have the linear dimension in the range from 10 to 100 nm. The powders of a capacitor class of specific capacity from 10 000 to 100 000 pC/g were obtained from nanocrystalline tantalum powder by agglomeration and deoxidation techniques. Nanocrystalline tantalum powders produced by SC «VNIINM» technology are a universal precursor for obtaining of high capacitor powders. (p. 121-126; fig. 8). 

S.A.Firstov, V.F.Gorban, N.A.Krapivka, E.P.Pechkovsky, M.V.Karpets

INFLUENCE OF CHARACTERISTICS CAST MULTICOMPONENT EQUIATOMIC TWO-PHASE ALLOYS ON THE QUANTITATIVE RELATION OF POLYCOMPONENT LAVES C14-PHASE AND BCC-SUBSTITUTIONAL SOLID SOLUTION.....................................................................................................127

On six cast five- and six-component equiatomic two-phase alloys containing a substitutional solid solution with BCC crystalline lattice (BCC-phase) and a polycomponent Laves C14-phase type MgZn₂ (C14-phase) connection of experimental certain quantitative relation of these two phases with calculation values for five characteristics of alloys is determined.

Alloys include metals Ti, Zr, V, Nb, Ta, Mo, Fe, Cr, Al; four metals Ti-Zr-V-Nb have made a base bottom of the studied alloys into which other metals were input by-turn. Following characteristics of alloys are used: properties of individual metals in chemical charge mixture composition; electron concentration Csd; atomic radius (relation of average values of atomic radiuses of metals with major radiuses R1 to that with small radiuses R2, i.e. R1/R2); an average enthalpy of mixture of metals in alloy DHmix; the total enthalpy of mixture of metals in all two-component C14-intermetallics in alloy SDHmix; the relative quantity two-component C14-intermetallics containing in an alloy. It is shown that each of these characteristics can be used individually for definition of quantity C 14-phase in the studied alloys, however in a different degree of approach to the experimental values. The most unequivocal communication is observed for such characteristic of an alloy as the relative quantity two-component C14-intermetallics in an alloy.

To regulate a relation of quantity C14-phase within 10-85 mass. % in two-phase alloys of the given type it is possible as by introduction in a base composition of the additional metals promoting formation two-component C14-intermetallics, and the metals promoting formation of the BCC-substitutional solid solution.

On the basis of the determined regularities of behaviour of the studied characteristics of alloys of the given type depending on their chemical charge mixture composition, and also the concrete effects gained in operation about connects between experementally gained and settlement parametres of alloys, it is obviously possible to predict the quantitative relation C14- and BCC-phases in alloys of a similar composition and also to construct new compositions (p. 127-144; fig. 5).

A.A.Skleznev, A.F.Razin

CONCRETE STRUCTURES WITH LATTICE COMPOSITE REINFORCEMENT............................................................................................145

The paper is concerned with the problem of concrete reinforcement with composites. Reinforcement located on the surface of concrete columns, utilization of composites instead of steel reinforcement and application of composite lattice structures as reinforcing elements are considered. Load-carrying capacity of the concrete column with composite lattice reinforcement is studied experimentally and compared with the corresponding characteristics of the concrete column and the column with steel reinforcement (p. 145-150; fig. 4).

Azarov A.V.

CONTINUUM MODEL OF COMPOSITE LATTICE SHELLS FORMED BY HELICAL RIBS.........................................................................151

The paper is concerned with the analysis of composite lattice structures consisting of systems of helical ribs. Deformation of the lattice cell formed by helical ribs under tension and shear is studied to specify the stiffness coefficients of the lattice structure which can be used to analyze lattice shells by using a continuum model. The obtained solutions are compared with results of the finite-element analysis and experimental data. Possible practical applications of composite lattice structures formed by systems of helical ribs are discussed (p. 151-161; fig. 7).

I.S.Deev, G.F.Zhelezina

FRACTOGRAPHIC ANALYSIS LAYERED METAL - POLYMER COMPOSITES ALOR THE TEST FOR FRACTURE TOUGHNESS................................................................162

Fractographic analysis of layered metal-polymeric composite ALOR based on unidirectional tape of SVM fibers and epoxy-rubber adhesive film VK-41 after fracture toughness tests in the mode I (in terms of separation) and mode II (in a shift). Shows the effect of pre-strain in tension of hardened composite fractographic features interlayer fracture when tested on crack. It is found that with increasing degree of preliminary plastic deformation changes the character of the fracture surface of the composite ALOR increases its fracture toughness and the peel and shear 1.5. The findings showed that the preliminary plastic deformation (0.5 - 1.0%) of hardened metal-polymer composite ALOR can be an effective way to improve its fracture toughness (p. 162-176; fig. 8).

R.M.Yakushev, S.N.Lysenko, S.Y.Ivanenko, D.E.Yakusheva

PREPARATION OF ELASTOMER NANOCOMPOSITE WITH CHEMICALLY BONDED NANOFILLER....................................................177

A polymer composite containing silica nanoparticles, chemically bonded to a polymer matrix was prepared. First, the dispersion of nanoparticles, stabilized by polyoxypropylene oligomer (PPO) with maleimide group at the free end of a molecule, in aprotic solvents was obtained. Then, the dispersion medium was replaced with bis-amino functional oligomer PPO. This was accompanied by Michael addition of amine groups to maleimide groups of the oligomer stabilizer and amino groups became free terminal ones. This dispersion was cured by bis-epoxy oligomer PPO to form a flexible polymer material with nanoparticles as elastomer crosslinking nodes (p. 177-182; fig. 4).

Krychkov V. A., Krychkov M. V., Vymorkov N.V., Portnova Y.M., Plyasunkova L.A., Bushansky N.V., Bushansky S.N.

NANOMODIFICATION OF CARBON FIBRE REINFORCED POLYMERS BY GRANULATED MULTILAYER CARBON NANOTUBES……………………….183

There are considered experimental results on introducing granules of multi-walled nanotubes (MWCNT) in an epoxy binder to obtain a fibre reinforced polymer with enhanced mechanical properties. A composite with reinforcing pattern simulating a shell structure of Proton rocket. It has been shown that using epoxy binder nanomodified by MWCNT allows enhancing mechanical characteristics of the composite and reducing the strength scatter down to 0.5 % (p. 183-190; fig. 3).

© MOTT PAH «Композиты и Наноструктуры». 2015