Computer simulation of multicomponent melts of metallurgical slags

E. V. Dyul’dina, B. R. Gelchinski, V. N. Selivanov

ABSTRACT

Based on the experimental data on the density, the molecular dynamics simulation of multicomponent oxide-fluoride metallurgical slag-forming systems: SiO2–CaO–Al2O3–MgO–CaF2–Na2O–K2O–FeO was carried out for the first time in the approximation of the ionic bond model. The results were discussed and compared with literary experimental and calculated data. The obtained model indicates a weak temperature dependence of the structure of the melt. An increased diffusion mobility of fluorine ions as well as ions of alkali metals in comparison with other elements has been revealed.

KEYWORDS

melt, metallurgical slag, computer simulation, structure, properties

DOI: 10.1134/S0235010618050055

Model investigation of liquid interaction metal and dispersed steel inclusions in castingon gasificable models

B. S. Vorontsov, N. V. Nesterov

ABSTRACT

A mathematical model for the interaction of liquid metal with metallic inclusions embedded in the foam polystyrene, reflecting the filling of molds, the effect of thermal decomposition of expanded polystyrene and heat exchange of the base alloy and filler material, is developed. The resulted results of the experiment on obtaining prototypes by casting on gasified models, confirming the predictions of mathematical modeling.

KEYWORDS

mathematical model, interaction of metal particles with melt, local alloying, casting for gasified models, composite materials

DOI: 10.1134/S0235010618050158

The fractals of five-pointed stars: deflationary and inflationary approaches

A. A. Polyakov

ABSTRACT

Inflationary and deflationary approaches to the constructing fractals from regular five-pointed stars are considered. Two types of descriptions of these approaches are proposed: absolute and relative. The relative description allows to formulate a simple connection between these approaches. Deflationary approach: at each stage of building a fractal, regular five-pointed stars of the same size and orientation are arranged so that their centers coincide with the vertices of the polygons of the previous step. The size of these stars at each step can be reduced in proportion to the integer degree of the golden mean; the orientation may coincide or be opposite to the orientation of the stars of the previous step. Inflationary approach: the prefractal of the previous step replicates, and the resulting figures are arranged so that their centers coincide with the vertices of a regular five-pointed star, increasing in size.

KEYWORDS

fractals, quasiperiodic lattice, quasicrystals

DOI: 10.7868/S0235010619010158

Thermodynamic analysis of joint aluminothermal recovery ZrO2 and Nb2O5

S. N. Agafonov, A. A. Ponomarenko, A. S. Russkikh

ABSTRACT

In this work, we studied the joint aluminothermic reduction of zirconium and niobium oxides. Thermodynamic modeling of metal-thermal reactions, differential thermal (DTA) and X-ray phase (XRF) analyzes were used in the work. The research can serve as a scientific basis for the development of promising metal-thermal technologies for the production of rare-metal alloys.

KEYWORDS

thermodynamic modeling, aluminothermic reduction, alloy, zirconium, aluminum, niobium, oxides

DOI: 10.7868/S023501061901002X

Studying the processes of producing alloys of the system of Fe–Si–Ni–Cr thermodynamic modeling

V. A. Salina, V. I. Zhuchkov, O. V. Zayakin

ABSTRACT

The results of thermodynamic modeling of the process of restoring the elements of a system containing, masses, are given. %: 40 Cr2O3; 21 FeO; 15 Al2O3; 6 SiO2; 16 MgO; 2 CaO; 0.006 P2O5 with increasing CaO content to basicity 3.15. Ferrosilicone (28% Fe, 65% Si; 7% Ni) is used as a reducing agent. For the simulation, the HSC Chemistry 6.12 software package developed by Outokumpu Research Oy (Finland) was used, the database of which introduced new thermodynamic constants for the CrO compound and corrected for CaCr2O4. It has been established that an increase in the degree of chromium reduction by 32.7% (from 64 to 95.1%) occurs in the interval of increasing the basicity of slag from 0.07 to 1.86. The rational basicity of slag is 1.86–1.9. Increased consumption of reducing agent from 0.5 to 1.05mred allows to increase the degree of chromium recovery by 52.4% and reach a value of 95.1%. The chemical composition of the resulting metal, wt %: 50.4 Cr; 1.97 Si; 3.3 Ni; 0.21 Al; 0.0050 P; Fe—the rest. The simulation results can be used to calculate the process of restoring elements of chrome ore using ferrosiliconikel.

KEYWORDS

thermodynamic modeling, system, silicothermia, basicity, reducing agent consumption, reduction degree, ferrosilicochromic nickel

DOI: 10.7868/S0235010619010183

Molecular model with supra-structural units alkaline borates

I. A. Babina, B. S. Vorontsov, V. V Moskvin, I. N. Grekhov

ABSTRACT

The use of semiempirical methods shows the possibility of building supra-structural units, with the exception of diborate group.

KEYWORDS

structural fragments, molecular model, with supra-structural units model experiment

DOI: 10.7868/S0235010619010031

Structure and properties of Ni–Al alloys in liquid state

A. G. Tyagunov, E. E. Baryshev, G. V. Tyagunov, K. Y. Shmakova, V. S. Mushnikov

ABSTRACT

The structure and properties of liquid Ni–Al alloys in a wide range of temperatures have been studied. Analysis of the temperature dependences of the physical and chemical properties of studied alloys discovered the phenomenon of hysteresis, i.e. discrepancy of heating and cooling politerm. This temperature is named hysteresis temperature. On the base of the quasichemical version of non-equilibrium melts structure offered a physical model of the structure of Ni–Al alloys. It is expected that after the melting liquid metal is in equilibrium state. It has as microgroups of NixCAl type with strong Ni–Al bond and GCC-like structure microgroups with more weaker bonds Ni–Ni. When the melt heated above liquidus temperature the size and lifetime of the cluster decreased. When the melt heated above critical temperatures clusters on NixAl type disappeared. Melt goes from micrononequilibrium to equilibrium state.

KEYWORDS

liquid metal, structure, properties, microgroup, quasichemical version of non-equilibrium melts structure, physical model of liquid

DOI: 10.7868/S0235010619010213

Formation of the structure and properties of multi-component iron based alloys in dependence on the conditions of the solidification of hydrogenated melts

R. M. Belyakova, V. A. Polukhin, N. I. Sidorov.

ABSTRACT:

The regularities of the behavior of the absorbed surfactant element (p.a.e.) of hydrogen on the peculiarities of the formation and phase structure in the multicomponent systems based on iron: steel, cast iron and alloys of the FINEMET group were studied. An analysis of the diffusion activity of elements with hydrogen adsorbed on them, hydrogen permeability, types of interatomic bonds as a result of interaction of elements and their influence on the functional properties of the products of structural design are carried out. The purpose of the work is to establish the nature of the interatomic bonds of adsorbed on the elements of the multi-component iron alloys of surface-active hydrogen and its influence on the functional and operational properties of the metal products under the changing conditions of their

structuring.

KEYWORDS:

interatomic interactions, types of bonds, polymorphic phase transitions, hydrogen, nanostructured phases, ferrite, graphite, carbides, structure and properties of matrices in products

DOI: 10.1134/S023501061805002X

Calculation of the spectrum of combination scattering of mollated calcium chloride by theory of density function theory

D. O. Zakiryanov, N. K. Tkachev.

ABSTRACT:

An ab initio approach is proposed that allows one to calculate the characteristic frequencies of the Raman spectrum of complexes in the composition of molten halides near the melting point. Within the framework of this approach, the structure of the molten salt is modeled by optimizing the structure of the nanoscale cluster in energy using the density functional theory (PBE functional) and basic sets of Gaussian type. It is shown that the partial radial atomic density functions obtained as a result of the analysis of the position of the atoms of a nanoscale cluster have a characteristic for ionic melts. This indicates the possibility of using a nanocluster to describe the structure of topologically disordered media with respect to spectroscopic problems. The spectra of various possible groups of the nearest environment of calcium were calculated consecutively: It was found that the eight-coordinate grouping in the nanoclusters gives the best agreement with experimentally observed at 161 cm–1 peak.

KEYWORDS:

calcium chloride, DFT, Raman spectroscopy

DOI: 10.7868/S023501061805016X

Simulation of redox reactions in liquid media with nonconstant force field molecular dynamics

A. A. Raskovalov, A. A. Latypov.

ABSTRACT:

In the paper application of non-constant force field molecular dynamics is shown for studying of redox reactions in liquid (molten) media. The method was applied to a system of ions. Interaction between these ions consisted of short-range Lennard-Jones and Coulombic pair potentials. Electron transfer between donor-acceptor pairs is implemented via special algorithms. Simulation results showed that concentrations of interacting ions changed during the simulations and reached some stationary values. Comparison between thermodynamics and the simulated results has revealed that difference in own energies of ions must include not only EMF value but additional terms too. It was shown that stationary concentrations depended on temperature, starting ion concentrations and a value of a solvent ionic radius. It was shown that the method can separate electronic transfer between different kinds of donor-acceptor pairs. In some simulations a system demonstrated behavior similar to Marcus “inverted region”.

KEYWORDS:

non-constant force field molecular dynamics, redox reactions, electron transfer, melt, Marcus theory

DOI: 10.1134/S0235010618060063