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

Magnetic properties and glass-forming ability of alloys CoFeSiBNb

V. A. Mikhailov, V. E. Sidorov, A. A. Sabirzyanov

ABSTRACT

In this paper, we studied the effect of small additions of tin, gallium, and zirconium on the magnetic properties of the Co48Fe25B19Si4Nb4 alloy at high temperatures. For the studied compositions, the temperature dependences of the magnetic susceptibility were obtained; the electronic characteristics were calculated: the effective magnetic moment, the density of electronic states at the Fermi level, the paramagnetic Curie temperature. On the basis of the alloys under consideration, amorphous samples were obtained by the methods of melt injection and suction casting.

KEYWORDS

alloys, magnetic properties, magnetic moment, Curie temperature

DOI: 10.7868/S0235010619010122

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

Structure of Al90Y10 alloy during crystallization under pressure

S. G. Menshikova, I. G. Shirinkina, I. G. Brodova, V.V. Brazhkin

ABSTRACT

X-ray diffraction analysis, optical and electron microscopy made a comparative study of the structure of the Al90Y10 alloy, nanotechnology and cooling technology, depending on the temperature and cooling rate of the melt. It is shown that under all considered crystallization conditions in the Al90Y10 alloy only crystalline phases are formed: α-Al and Al3Y. The influence of temperature, cooling rate and pressure on the morphology, size and microhardness of the structural constituents of the alloy-primary yttrium aluminide and eutectic crystals was established.

KEYWORDS

aluminum-based alloy, melt temperature, melt cooling, pressure, phase, microhardness, microstructure, electron microscopy

DOI: 10.7868/S0235010619010110

Calorimetric study of liquid Ag–Cu–Sn alloys formation. Mixing entalpy in boundary binary systems Cu–Ag, Cu–Sn and Ag–Sn at 1150°C

K. I. Oleinik, A. S. Bykov

ABSTRACT

The processes of liquid alloys Cu–Ag, Cu–Sn and Ag–Sn systems were investigated by drop calorimetry method at a temperature of 1150°C. Pure components of the formed alloys and standard sapphire samples were used for the calorimeter sensitivity calibration. Experimental results were described by analytical expressions using the quasichemical approximation of models of subregular solutions. The obtained data are necessary to study the characteristics of alloy formation in the ternary system Ag–Cu–Sn.

KEYWORDS

thermodynamic properties, calorimetry, heat of mixing, Cu–Ag alloy, Cu–Sn alloy, Ag–Sn alloy

DOI: 10.7868/S0235010619010146

Study of structure and alloys properties of Fe–Ni–Co–(Cu,Cr) system with the use of experimental methods

S. I. Sinyova, R. V. Starykh, O. S. Novoghilova, A. A. Vasil’eva, D. К. Gol’dvirt

ABSTRACT

The work is devoted to the determination of temperature and composition area of solid solution, existed at Fe–Ni–Co–(Cu, Cr) system. It is well-known, that alloys of this system are the new type of materials, characterized by high entropy of mixing. Design of high entropy alloys (HEAs) with desired properties is modern trend in materials science nowadays, and number of articles, related to the discussed topic, is constantly increasing. Authors of the current work came down to the design and analysis of HEAs from the thermodynamic point of view, based on the own experience in experimental investigation of phase diagrams of multicomponent metallic systems Research is provided with the use of classical physicochemical methods of phase diagram construction, namely, differential thermal analysis, electron probe microanalysis, X-ray diffraction analysis and scanning electron microscopy. During the first step of research the liquidus and solidus surface projections of the Fe–Ni–Co–Cu quaternary system have been constructed. There were defined the limits of solid-state miscibility gap and tie-lines location within the discussed miscibility gap. In such a way we defined the area of quaternary solid solution, within the volume of that the HEAs can be synthesized. The next step of research is determination of temperature and composition areas of solid solution in Fe–Ni–Co–(Cu, Cr) system. The effect of addition of Cu and Cr on the structure, phase composition and properties of obtained alloys has been shown. Obtained information could be useful as basis for design of HEAs.

KEYWORDS

high entropy alloys, HEAs, phase equilibria, Fe–Ni–Co–(Cu,Cr), heterogeneous system, thermal analysis

DOI: 10.7868/S0235010619010195

Activity of oxygen in nickel melts containing aluminum, lanthanum and cerium at PAr = 0.1 MPa

V. T. Burtsev.

ABSTRACT:

The deoxidation of nickelEbase superalloys upon vacuum melting was carried out in the presence of Al with strong deoxidizers such as La and Ce. The oxygen activity (a[O]) in the Ni–O–Al (0.001–5%), Ni–O–La/Ce (0.001–0.1%) and Ni–O–Al (5%)–La/Ce (0.001–0.1%) melts at 1560°C and PAr = 0.1 MPa has been studied by the method of instantaneous EMF recording by certified sensors. For the former two melting systems, the a[O] = f[Al/La/Ce%] dependences are described by logarithmic functions. The deoxidizing ability of Ce in the second system is higher by a factor of 4.7 than that of La. For the melts of the third system, the a[O] = f[Al (5%)–La/Ce] dependences constructed in the “spline” regime showed that the introduction of La (0.02–0.05%) decreases a[O] by a factor of 6–8 relative to the data on the second system of melts, and the introduction of Ce (0.02–0.05%) decreases a[O] by a factor of 3–3.4 relative to the data on the second system of melts, and the deoxidizing capacity of Ce remains higher than that of La in the presence of aluminum. Therefore, Ce is preferable as the final oxidizer in the practice of deoxidation.

KEYWORDS:

Nickel-oxygen-aluminum melts, lanthanum, cerium, EMF method, deoxidation

DOI: 10.7868/S0235010618050043

Conditions and stages of flotation of gold dispersed drops in silicate melts

N. A. Vatolin, A. M. Amdur, V. V. Pavlov, S. A. Fedorov.

ABSTRACT:

The flotation of droplets in liquids occurs frequently. For example, the flotation is the basis for the removal of liquid non-metallic inclusions from steel. Meanwhile, the mechanism of this process is has not been sufficiently studied. The paper describes in detail the mechanism of flotation of metal droplets in the melt for example of gold: the kinetics and formation stages of the gas bubble–gold droplet system, as well as the subsequent gold flotation in the melt, are considered. Once a gas bubble and a micro-droplet have concerned, a third surface gold–gas and a wetting perimeter appear, in addition to the previously existing melt-gas (around the bubble) and gold–melt (around the droplet) surfaces. The time for achieving equilibrium for gold micro-droplets with a radius of about 3 μm has an order of 10–4 s. Consequently, the formation of an equilibrium bubble-drop system is occurs rapidly and does not hinder the overall process of collecting and fusion of gold micro-droplets by gas bubbles. The flotation condition providing an excess of the interfacial tension forces over the gravity force is analyzed in relation to the system of dispersed droplets (gold, platinum and palladium)—oxide melt. This condition holds for metal droplets with a radius of up to 3500 μm.

KEYWORDS:

flotation, spreading, gas bubble, droplet, interphase tension, wetting perimeter, wetting angle, gold

DOI: 10.1134/S0235010618060075

The effect of calcium-containing additives on the extraction of alumina from red muds of alumina production

S. A. Bibanayeva, V. N. Koryukov, V. M. Skachkov, N. A. Sabirzyanov, V. M. Ufimtsev, E.M. Lebedeva

ABSTRACT

The results of an experimental study of the effect of calcium-containing reagents on the process of high-temperature autoclave extraction of alumina from red muds obtained from Timan deposit bauxites by the parallel Bayer-sintering method are presented. The phase composition of products is determined by XRD and EDXR methods. Increased extraction of alumina from red mud when used the surface-carbonized lime in the process is shown.

KEYWORDS

red mud, processing, leaching, calcium oxide

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 slagFforming 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