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It has been shown that the effect of structural inheritance in casting eutectic cast irons can be explained from the standpoint of nanostructured crystallization of foundry alloys. Proposed is a mechanism of structural heredity when casting eutectic cast irons. This mechanism is determined by the stability of the crystallization centers of microcrystals of austenite, graphite, cementite. This stability has been shown to depend on the concentration of adsorbed oxygen atoms. The higher this concentration, the less stable the centers of crystallization of microcrystals of austenite, graphite, cementite in melts of eutectic cast irons, and vice versa. With an increase in overheating and (or) the holding time of melts, the concentration of adsorbed oxygen atoms in them increases. As a result, structural stability during remelting of eutectic cast irons is reduced and the effect of structural heredity is disturbed.

A nanostructural mechanism of secondary transformations in the structure of gray cast iron is proposed. First, structureforming nanocrystals of austenite, ferrite, cementite and graphite are formed from elementary nanocrystals of iron and graphite, free atoms of iron and carbon. The crystallization centers of microcrystals of phases are formed from them. From these centers, structure‑forming nanocrystals of phases, free iron and carbon atoms, microcrystals of austenite, ferrite, cementite and graphite of binary gray cast irons are formed.

A nanostructural mechanism for recrystallization of binary aluminum and tin bronzes has been developed. First, structure-forming nanocrystals of α-phases, β-phases and γ-phases are formed from elementary nanocrystals of copper, aluminum, tin and their free atoms. The crystallization centers of microcrystals of phases are formed from them. From these centers, structure-forming nanocrystals of phases, free atoms of copper, aluminum, tin, microcrystals of α-phases, β-phases and γ-phases of binary aluminum and tin bronzes are formed.

Based on thermodynamic calculations, it is shown that heating and cooling of metals and alloys are reversible, equilibrium processes. Based on thermodynamic calculations, it is shown that melting and crystallization of metals and alloys are also reversible, equilibrium processes. With an increase in the cooling rate of the metal, the temperature of its equilibrium crystallization decreases. At a high rate of metal cooling, a short‑term initial process of nonequilibrium crystallization is observed, which quickly passes into the main stage of equilibrium crystallization.

A nanostructural mechanism of structural stability during remelting of foundry binary alloys has been developed. This mechanism is determined by the stability of the centers of crystallization of microcrystals of α‑phases and β‑phases. It is shown that this stability depends on the concentration of adsorbed hydrogen and oxygen atoms. The higher these concentrations, the less stable the centers of crystallization of α‑phase and β‑phase microcrystals in melts of foundry binary alloys, and vice versa. With an increase in overheating and (or) the holding time of melts of foundry binary alloys, the concentrations of adsorbed hydrogen and oxygen atoms in them increase. As a result, structural stability decreases during the remelting of foundry binary alloys.

It is shown that devices in the form of a water‑cooled metal mold with a graphite lining, which is located on the upper surface of the casting close to the end of the crystallizer, can serve as an alternative to secondary water‑air cooling systems in horizontal continuous casting. The effectiveness of the cooling capacity of the molds was evaluated during industrial tests of the devices in the process of casting iron. It has been established that the use of water‑cooled molds allows reducing the surface temperature at vulnerable points of the casting by 20–70 °C, increasing the average casting speed for individual billet sizes within 5–8 % almost eliminating shell breakout and eliminating the need for traditional secondary cooling systems.

It is shown that the main modifying intermetallides of primary microcrystals of aluminum alloys do not satisfy the principle of structural and dimensional correspondence. Nonmetallic inclusions and intermetallides cannot be centers of crystallization of metallic melts. These centers are nanostructured formations formed from structure‑forming nanocrystals of crystallizing microcrystals of phases and free atoms of alloy components. Such crystallization centers of metal melts satisfy the principle of structural and dimensional correspondence. The main mechanism of action of casting alloy modifiers is a significant decrease in the concentration of surfactants, which reduce the concentration of crystallization centers of metal melts.

A nanostructural mechanism for recrystallization of carbon steels has been developed. First, structure‑forming nanocrystals of austenite, ferrite and cementite are formed from elementary nanocrystals of iron and graphite, free iron and carbon atoms. The crystallization centers of microcrystals of phases are formed from them. From these centers, structure‑forming nanocrystals of phases, free iron and carbon atoms, microcrystals of austenite, ferrite and cementite of carbon steels are formed.

It is shown that the open pores of the crystal lattices of iron, manganese, titanium, cobalt cannot contain hydrogen, oxygen, nitrogen and carbon atoms. In solid solutions of alloys, hydrogen and oxygen atoms are present in the adsorbed state. Nitrogen atoms are mainly included in metal nitrides. Carbon atoms are found in elementary graphite nanocrystals. In solid solutions of alloys consisting of metals, their atoms are part of nanocrystals. They mainly consist of metal alloys. The formation of solid solutions of alloys is a nanostructural process.

It is shown that the main modifying phases cannot serve as centers of crystallization of α‑phase microcrystals during solidification of magnesium‑manganese alloys.The superheating modification of these alloys is an adsorption‑nanostructural process. It is shown that adsorbed hydrogen acts as a modifying element of the structure of castings of magnesium‑manganese alloys. The mechanism of their modification by overheating consists of a significant decrease in the concentration of adsorbed hydrogen due to the predominance of its desorption processes from elementary magnesium and manganese nanocrystals in liquid magnesiummanganese alloys. The mechanism of modification of the main modifying phases of these alloys consists of a significant decrease in the concentration of adsorbed hydrogen in the melts through a significant decrease in the concentration of dissolved hydrogen.

It is shown that hydrogen atoms in carbon steel melts are surface‑active elements for aluminum oxide microcrystals. Adsorbed hydrogen atoms reduce the interfacial surface energy and increase the resistance of small aluminum oxide microcrystals to coagulation. To reduce their stability in liquid carbon steels, it is necessary to reduce the concentration of dissolved hydrogen in them. Active modifiers reduce the concentration of adsorbed hydrogen. This enhances the process of coagulation of small microcrystals of aluminum oxide into larger particles that can quickly float in the melt.

It is shown that the main modifiers of foundry magnesium alloys cannot create heterogeneous crystallization centers in melts during their solidification. Modification of alloy structures is an adsorption‑nanostructural process. It is shown that adsorbed hydrogen is a modifying element of the structures of foundry magnesium alloys. The mechanism of their modification consists in a large decrease in the concentration of adsorbed hydrogen in melts by significantly reducing the concentration of dissolved hydrogen.

It is shown that hydrogen is a demodifying element of primary structures of tin and aluminum bronzes during their crystallization. The mechanism of influence of hydrogen on the formation of primary structures of tin and aluminum bronzes can be explained from the position of nanostructured crystallization of casting alloys. Hydrogen atoms adsorbed on elementary nanocrystals in melts prevent the combination of nanocrystals into nuclei of crystallization of microcrystals α‑phases of tin and aluminum bronzes. The result is castings with unmodified primary structures. The modifiers reduce the concentration of adsorbed hydrogen in the melts of tin and aluminum bronzes. This results in the milling of the primary phase microcrystals in the castings as they solidify.

It is shown that eutectoid reactions of binary alloys are nanostructural processes. The main phase, which decays during the eutectoid reaction, is formed during the crystallization of a metal melt of eutectoid composition. This process is nanostructured. In it, the main elements of microcrystals are the nanocrystals of the alloy components. During the eutectoid reaction, the microcrystals of the main phase disintegrate into nanocrystals. Microcrystals of the other two phases are formed from them.

It has been shown that elementary crystal lattices of basic phases and oxides of casting alloys do not satisfy the principle of structural and dimensional correspondence. Formation of crystallization centers during solidification of casting alloys is a nanostructured process. The main demodifying element in melt crystallization is adsorbed hydrogen. It prevents the integration of nanocrystals into the nucleus of crystallization of the main phases of casting alloys. When the melt overheats, adsorption and desorption of hydrogen atoms occur. The predominance of one of these processes explains the features of crystallization of cast‑ ingalloys. Prior to critical superheating of the melt, the adsorption of hydrogen atoms prevails. As a result, molds with an unmodified structure are formed. When the melt overheats above the critical one, the process of desorption of hydrogen atoms prevails. As a result, molds with a modified structure are formed.

It has been shown that elementary crystalline cells of α‑phases of tin, aluminum bronzes and main modifying phases do not correspond to the principle of structural and dimensional correspondence of Dankov‑Konobeevsky. Modifying structures in tin and aluminum bronze castings is a nanostructured process. The main role of tin and aluminum bronze modifiers is to significantly reduce the concentration of adsorbed hydrogen, which prevents the formation of crystallization centers of α‑phase microcrystals in castings when they solidify.

It has been shown that the main influence on the crystallization of heat‑resistant chromium steels is hydrogen. It is a demodifying element of the casting structure. The mechanism of the influence of hydrogen on the crystallization of heat‑resistant chromium steels can be explained from the position of nanostructured crystallization of casting alloys. Dissolved hydrogen atoms, adsorbing on elementary nanocrystals of iron and chromium in melts of heat‑resistant chromium steels, prevent the combination of nanocrystals into nuclei of crystallization of α‑phase microcrystals. As a result, castings with an unmodified structure are obtained. Reduction of hydrogen concentration in melts of heat‑resistant chromium steels contributes to formation of modified structure in castings at their hardening.

An analysis of the state of foundry production in the world is presented, as well as an analysis of the state of foundry production in the Republic of Belarus. The dynamics of changes in production capacities, the degree of loading and the volume of production of castings for various types of alloys is shown. It is established that the structure of cast products produced both in the world and in the Republic of Belarus is in constant dynamics and there is a constant change in the ratio of production volumes from various alloys. The development of the foundry production of the Republic of Belarus as a whole is similar to the world foundry production, however, there is a certain time lag and certain differences in the ratio for different types of casting.

It is shown that hydrogen is a demodifying element of the structure of cast magnesium alloys during their crystallization. Hydrogen atoms, adsorbing on elementary nanocrystals in melts, prevent the combination of nanocrystals into the nucleus of crystallization of α‑phase microcrystals. As a result, molds with an unmodified structure are formed. Modifiers reduce the concentration of adsorbed hydrogen in the melts of magnesium alloys. This results in the milling of α‑phase microcrystals in castings as they solidify.

It has been experimentally shown that directional solidification of water and bismuth in glass and quartz cylindrical forms does not result in expansion of the castings perpendicular to the solidification direction. Therefore, such forms are not destroyed. This is due to the unobstructed release of gases during directional solidification of water and bismuth. Gases have a great influence on the expansion processes of castings when they solidify.

It has been shown that elementary crystalline cells of graphite and basic products of iron modification do not correspond to the principle of structural and dimensional correspondence of Dankov –Konobeevsky. Modifying elements Al, Ca, Mg, Ba, Ce increase the phase tension melt‑graphite by binding surface‑active oxygen and sulfur. Modifying cast iron eutectic graphite is a nanostructured process in which modifying elements refine elemental graphite nanocrystals from adsorbed oxygen and sulfur atoms. This contributes to an increase in the concentration of graphite nuclei upon solidification of the cast iron melt. The modification reduces the concentration of dissolved hydrogen, which increases the effectiveness of the modifying effect. Reduced concentrations of demodifying surface‑active elements, melt degassing, increased heat removal contribute to increasing the degree of branching and compactness of graphite dendrites during iron crystallization. The strongest modifying element of eutectic cast iron graphite is magnesium.

It has been shown that the elementary crystal cells of the basic products of modification of silumins, aluminum and silicon do not correspond to the principle of structural and dimensional correspondence of Dankov – Konobeevsky. Modifying elements B, Sr, P significantly increase the surface energy of liquid silumins, and Zr and Ti practically do not affect it. Modification of silumins is a nanostructured process. Ti, Zr, B form intermetallides that refine aluminum nanocrystals from demodifying adsorbed hydrogen atoms. Phosphorus, atomically dissolving in silumin, refiners silicon nanocrystals from adsorbed oxygen. Na and Sr form an emulsion and colloid in liquid silumin, which protect eutectic microcrystals of α‑and βSi‑phases from demodifying molecular hydrogen. All these processes increase the concentration of crystallization centers of dendritic microcrystals α‑and βSi‑phase, make them more branched and compact.

It has been shown that the elementary crystal cells of the basic products of deoxidation and modification of carbon steel, δ ferrite and austenite do not correspond to the principle of structural and dimensional correspondence of Dankov – Konobeevsky. Modifying elements Ba, Ca, Mg, Ce, Al increase the surface energy of the iron‑carbonaceous melt by binding surface active oxygen. Deoxidizers combine dissolved (free) oxygen into oxides, and modifiers – adsorbed oxygen. Steel modification is a nanostructural process in which modifying elements refine elemental iron nanocrystals from adsorbed oxygen and hydrogen atoms. Modifying elements reduce the concentration of dissolved hydrogen, which contributes to the modifying effect. The strongest deoxidizer and modifier of carbon steel is magnesium.

It has been shown that hydrogen and oxygen atoms cannot be present in the open pores of crystal lattices of base metals of casting alloys. The solubility of gases in liquid casting alloys is a nanostructured process. Hydrogen and oxygen atoms in melts are adsorbed by basic metal elemental nanocrystals. Nitrogen dissolves in liquid iron, nickel and chromium not in atomic form, but in the composition of elementary nanocrystals and nitride molecules. After deoxidation of molten casting alloys, the main gas dissolved in them is hydrogen.

Crystallization of casting alloys has been shown to be a nanostructured process. Microcrystals of phases in the temperature range of liquidus and solidus, during eutectic and peritectic reactions, are formed from nanocrystals of components A and B of alloys, their free atoms and atomic complexes. Microcrystals of primary austenite and austenite-graphite eutectics during crystallization of cast iron, microcrystals of austenite and δ-ferrite during crystallization of steel are formed as a result of nanostructural reactions from elementary nanocrystals of iron and graphite, free atoms of iron and graphite, iron-carbon complexes. Primary and eutectic microcrystals of silumin are formed from elementary nanocrystals of aluminum and silicon, free atoms of aluminum and silicon, aluminum-silicon complexes.

A technique that allows calculating the values of the specific heat flux in a given range of values of the technological parameters of casting and the maximum allowable thickness of the casting crust at the outlet of the mold is proposed. The information on the temperature regime of the mold at various casting parameters can serve as a database containing the necessary information to solve the casting solidification problems. With the subsequent design of tooling and equipment, there is no need for additional experimental studies and analysis of the results obtained.

It is shown that during developing continuous casting technology, it is necessary to solve a number of tasks related to finding the optimal technology option, creating special equipment to expand the range of cast blanks and calculating optimal parameters. The profile, dimensions and material of the blanks determine the continuous casting method choice and the installation type. Designs of the most important components and mechanisms are being developed for the selected type of installation. For the selected design solution, based on the lesson learned and available research, optimal thermal and technological parameters of casting are calculated.

Thermodynamic calculations have shown that hydrogen from atmospheric water vapors can penetrate aluminum, iron and copper, especially into their melts. Hydrogen atoms in these metals are in free and adsorbed states. Strong and dense oxide films on the surfaces of aluminum, iron and copper significantly reduce the solubility of hydrogen in these metals. Copper and iron nanocrystals more actively adsorb atomic hydrogen than aluminum nanocrystals. This is one of the main reasons for the weak solubility of hydrogen in aluminum and the large desorption of hydrogen atoms in the crystallization of aluminum compared to iron and copper.

The classical theory of crystallization of metal melts has been investigated. It is shown that it does not correspond to the second law of thermodynamics. Based on thermodynamic analysis, it was found that the classical theory of crystallization of metal melts is very problematic. To solve theoretical problems, it must be considered that the crystallization of metal melts is mainly an equilibrium process in which nanocrystals play a major role.

Recrystallization of iron-carbon alloys has been shown to be a nanostructured process. Microcrystals of secondary cementite of steels and cast iron are formed from elementary nanocrystals of iron and graphite, free atoms of graphite and iron-carbon complexes. Microcrystals of primary α-ferrita steels are formed from elementary nanocrystals of iron and graphite, free iron atoms. Microcrystals of cast iron secondary graphite are formed from elementary nanocrystals and free graphite atoms. Eutectoid microcrystals are formed from elementary nanocrystals of iron and carbon, free atoms of iron and carbon, iron-carbon complexes.

The established regularities of the formation of powders based on iron and nickel, obtained by the method of mechanical alloying and intended for the deposition of thermal spraying coatings, as well as the manufacture of products by layer‑by‑layer synthesis. The structure, phase composition and properties of materials are investigated. Powders consist of particles with a size of 20–70 microns, differ in the submicrocrystalline type structures, and nonequilibrium phase composition. Thermal spray coatings made of them have a set of properties that significantly exceed the properties of coatings made of commercially available materials. The diameter of the grains of the material obtained by the SLМ method from the synthesized powder is 1.5–2.0 times smaller than that produced from the powder of 316L steel, and the heat resistance is higher.

Despite a significant amount of work in the field of mechanically doped alloys and, above all, based on aluminum and copper, research aimed at creating mechanically doped alloys is extremely limited. In this regard, the following work aimed at to establishing the regularities of the formation of the phase composition, structure, and properties in the implementation of the technology for obtaining mechanically doped heat‑resistant steels, is important and relevant.The basis for the development of mechanically doped alloys were the results of long‑term research carried out at the Belarusian‑Russian University and aimed at studying mechanically and thermally activated structural phase transformations taking place at all the technological stages of obtaining mechanically doped metal alloys. In this article, in a generalized form the final research results are presented, revealing the patterns of these transformations, which are a reliable scientific basis for the creation of mechanically doped complex‑hardened heat‑resistant steels.

Method of calculation of thermodynamic parameters of metals has been developed. Based on the thermodynamic parameters of the metals, it is shown that the Gibbs molar volumetric energy has a negative value. When metals are heated, Gibbs molar volumetric energy decreases. The heating and cooling processes are reversible. Metal crystallization occurs under thermodynamically equilibrium conditions.

Based on thermodynamic calculations, it is shown that in the temperature range of 298–1273 K, heating and cooling of aluminum are thermodynamically equilibrium processes. When aluminum is heated, the molar volume energy of Gibbs decreases and the molar boundary energy of nanocrystals increases. When aluminum is cooled, the molar volume energy of Gibbs increases and the molar boundary energy of nanocrystals decreases. Liquid aluminum is a nanostructured system. Dendritic microcrystals are formed from nanocrystals. They play a large role in the processes of changing the structure of aluminum during its heating and cooling.

Steel crystallization has been shown to be a nanostructured process. Austenite microcrystals in liquid steel with a carbon concentration of 2.5 to 9 atomic percent, δ‑ferrite microcrystals in melt with a carbon concentration of up to 2.5 atomic percent, austenite microcrystals in peritectic reaction are formed from elementary nanocrystals of iron and graphite, free iron atoms and iron‑carbon complexes.

Gibbs molar volumetric energy and iron boundary molar energy are determined depending on temperature. It has been shown that phase transformations in iron occur under thermodynamically equilibrium conditions. The iron phase microcrystals are dendrites. Crystallization of the iron melt is a nanostructural process. Iron recrystallization has been shown to be a largely diffuse process.

Based on the calculations of the model of the elementary crystal cell γ‑iron, it is shown that carbon ions cannot be present in its open pores. Carbon in Fe‑C alloys dissolves and distributes mainly as elementary graphite nanocrystals. In steel austenite, carbon is found in elementary graphite nanocrystals and in iron‑carbon complexes. In cast iron austenite, carbon is found in elementary graphite nanocrystals.

The crystallization of silumins has been shown to be a nanostructured process. Liquid silumin consists of elementary nanocrystals of aluminum and silicon, free atoms of aluminum and silicon, aluminum-silicon complexes. Primary microcrystals are formed from them. Eutectic microcrystals are formed from elementary nanocrystals of silicon and aluminum, aluminumsilicon complexes.

Crystallization of cast iron has been shown to be a nanostructured process. Austenitic-graphite eutectic is formed from iron and graphite nanocrystals, free iron and graphite atoms. Austenitic-cementite eutectic is formed from iron and graphite nanocrystals, free graphite atoms and iron-carbon complexes. Primary austenite microcrystals are formed from iron nanocrystals, graphite and iron-carbon complexes.

Based on thermodynamic calculations, it is shown that metal crystallization is an equilibrium nanostructural process. At the beginning, trigonal or tetragonal structure-forming nanocrystals are formed from elementary nanocrystals. Then crystallization centers are formed from them. Further, tetragonal or hexagonal dendrites are formed from them and tetragonal or trigonal structure-forming nanocrystals. Their forms depend on the degree of branching of dendrites. The most branched of them (compact dendrites) are tetragonal or hexagonal crystals.

Method of calculation and calculated values of parameters of elementary nanocrystals of liquid metals at melting temperature are given. It has been shown that radii of elementary nanocrystals are from 2 nm to 12 nm, and the number of atoms in each elementary nanocrystal varies from 2000 to 100000. This provides liquid metals with a high solidification rate and explains the abnormally high diffusion coefficient in liquid metals compared to solid metals.

Aspects of thermal phenomena associated with the production process of bimetallic billets in conditions of small penetration depths of eddy currents compared to the size of the heated body are considered. Various conditions of heat distribution in the heated layer and its removal are modeled using differentiated thermal resistance. Based on the analysis of the temperature distribution in various situational variants, promising ways to improve this technology are identified.

Thermodynamic calculations of the structure of metal melts, processes of their crystallization and degassing in the eutectic reaction have been made. It is shown. That the main structural elements are nanocrystals, and hydrogen bubbles have a direct effect on the morphology of eutectic crystals and the phase structuring process. Physical and chemical principles and mechanisms for modifying the microstructure of silumins have been developed. It has been found that the main processes affecting the modification of phase crystals are the intensity of coagulation of nanocrystals, refining from adsorbed oxygen and hydrogen atoms, and preventing the release of hydrogen bubbles on eutectic crystals. Environmentally safe methods of casting silumins with highly dispersed inverted microstructure are developed, based on mixing of liquid metal and liquid-hard alloy, accelerated hardening and structural-hereditary modification. Antifriction silumin has been developed, which in terms of friction wear resistance exceeds and replaces industrial aluminium and tin bronzes, but is cheaper and lighter in 2–3 times. Universal silumin modifiers for steel, bronze, cast iron, brass have been developed. Devices and crystallizers with a flood-jet cooling system have been developed, which are 2–3 times more effective than normal ones. Experimental-industrial casting section for production of solid and hollow billets from silumins with highly dispersed inverted microstructure has been created. These pieces are supplied to more than 100 industrial enterprises of Belarus, Russia, Korea and Ukraine.

This paper presents approaches to the computational analysis of solidification and cooling processes of continuously cast billets in order to improve and develop technological modes in the conditions of modern continuous casting machines using FEM.The application of modern numerical methods for solidification and cooling of workpieces on continuous casting machines is considered. The use of the finite element method is justified when using computational and experimental data for the development and improvement of casting technology.

The results of experimental studies to determine the effect of alloying and heat treatment on the mechanical properties of the high-chromium cast iron are described. When alloying the melt with nickel, molybdenum and manganese, as well as during heat treatment by quenching, specific wear, tensile strength in bending of the obtained samples, their hardness and microhardness were studied. A comparative analysis of the influence of alloying elements and heat treatment methods has been performed. When alloying Ni, Mo, and Mn, cast specimens that have not undergone heat treatment have the highest specific wear. It was established that the hardened Ni alloyed samples have the greatest bending strength. It was found that cast samples that were not subjected to heat treatment have much lower hardness and microhardness. The approximate composition of chromium cast iron was determined for further studies to increase its wear resistance. The research results are used in the manufacturing process of parts for crushing and grinding equipment.

The option of creating a composite material based on high manganese steel by the method of dynamic alloying in the superdeep penetration mode by flows of powder particles is considered. The dynamic effect of powdered microparticles on a matrix billet transforms the original cast steel into a composite material and leads to a change in mechanical properties.

The effect of heat treatment on the structural-phase state and hardness of small-sized castings made from the Cu-Cr-Al copper alloy obtained by casting in a water-cooled metal mold is studied. Using X-ray diffraction analysis, it was found that the castings consist of a matrix solid solution based on copper. The increased value of the crystal lattice parameter of the copper phase is associated with aluminum atoms dissolved in it. After a low-temperature (450 °C) tempering for 10 hours, the crystal lattice parameter of the matrix solid solution decreases, which is associated with the formation of the Al8Cr5 intermetallic compound on the surface of the casting.It is established that after heat treatment (hardening and tempering), the hardness of castings from the Cu-Cr-Al alloy increases by 1.5 times.

On the basis of thermodynamic calculations it is shown that crystallization of metals is a thermodynamic process, which takes place mainly at constant temperature. The exception is crystallization at very high cooling rates of the metal melt when the released solidification heat is not enough to stabilize the crystallization temperature of the liquid metal. In crystallization, the specific interfacial surface energy of crystals is not a constant value, but is proportional to their dimensions (bend radius).Nanocrystals of crystallizing phases exist in the metal melt steadily. Metal crystallization aggregates nanocrystals and free metal melt atoms into microcrystals. Mechanism of dendritic crystallization of metals is proposed.

Based on thermodynamic calculations, it is shown that metal melting is an equilibrium process that occurs at a constant temperature. In melting, microcrystals mainly disintegrate into nanocrystals. Metal melt is a twophase system consisting of nanocrystals and atomic gas. Nanocrystals ranging in size from one to hundreds of nanometers exist stably in the metal melt.

The technique of physical modeling of macro processes of solidification of castings on transparent models and liquids has been developed. The model liquids may be water with different salt contents. Glass bottles can be used for transparent models. Thermal insulation of the top of the model is required. The developed technique allows to investigate the effect of dissolved gases on the microstructure of castings. It has been shown that gases dissolved in liquids have a direct effect on the solidification process and its kinetics. It has been shown that hot water containing less dissolved air than cold water solidifies in the freezer faster than cold water.