A. V. Koltygin

Verified

A. verified their affiliation via an institutional email.

Learn more

Verified

A. verified their affiliation via an institutional email.

Learn more

• PhD
• Lecturer at National University of Science and Technology

The finite-element-analysis-based computational system of ProCAST is used for computer modeling of the production of an ingot and its piercing on a press. The results are then recoded for the finite-element computing environment of DEFORM-3D, which is used to model the piercing of the ingot on the press. The effect of the deformation the ingot duri...

The effect of rotary swaging (RS) on the microstructure, mechanical properties, corrosion resistance and biocompatibility in vitro and in vivo of the Zn-1Mg-0.1Mn (wt.%) alloy was studied in this work. A structure with α-Zn grains elongated along the deformation direction and spherical particles of the eutectic phase are formed in the Zn-1Mg-0.1Mn...

Binder jetting is the most widely implemented additive technology for the fabrication of sand molds. However, the use of furan binder-jetting technology in the production of molds for vacuum casting is hindered by the thermal destruction of the furan binder accompanied by violent gas emission that occurs during the mold heating process. This invest...

Magnesium-based biodegradable implants are designed to replace permanent implants, eliminating the demand for implant removal by secondary surgery. The Mg-Y-Zn-Mn alloys are outstanding solutions for biomedical purposes due to their superior mechanical properties and moderate biodegradability. This research examines the effect of Y and Zn content a...

The phase composition of VZhL14N-VI nickel superalloy was analyzed in a wide temperature range – from room temperature to 1600 °C by means of CALPHAD (CALculation of PHAse Diagrams) calculations. In light of the findings, the authors devised potential heat treatment modes for VZhL14N-VI superalloy. The impact of different heat treatment modes on th...

The microstructure, mechanical properties and corrosion resistance of promising medical Zn-1% Mg-0.1% Dy and Zn-1% Mg-0.1% Mn alloys after high-pressure torsion (HPT) are studied. It is shown that the HPT results in formation of an ultrafine-grained structure of a-Zn with grain size 450-700 nm in both alloys. The grain-boundary magnesium phase is r...

In the domain of metal casting, investment casting is recognized for its proficiency in producing high-quality castings. This method involves the utilization of a melt out, burnout, or soluble patterns to create ceramic molds. The present investigation explored the potential of utilizing fused deposition modeling (FDM) patterns fabricated from poly...

Complex studies of new Mg-Zn-Y-Zr system alloys have been carried out. The content range for the formation of the two-phase structure MgSS (Mg solid solution) + LPSO (long-period stacking ordered) in alloys of the Mg-Zn-Y-Zr system was determined by thermodynamic calculations. The effect of heat treatment regimes on microstructure, mechanical, and...

Investment casting is a widely utilized casting technique that offers superior dimensional accuracy and surface quality. In this method, the wax patterns are employed in the layer-by-layer formation of a shell mold. As is customary, the patterns were created through the injection of molten or semi-solid wax into the die. The quality of the final ca...

Magnesium alloys are considered as promising materials for use as biodegradable implants due to their biocompatibility and similarity to human bone properties. However, their high corrosion rate in bodily fluids limits their use. To address this issue, amorphization can be used to inhibit microgalvanic corrosion and increase corrosion resistance. T...

A comparative study of the structure and properties of two biodegradable Fe – 27Mn and Fe – 27Mn – C alloys for biomedical use after equal channel angular pressing (ECAP) has been carried out. It is noted that addition of carbon in the alloy leads to a change in the mechanism of plastic deformation from the formation of martensite to deformation tw...

The article presents the results of the study of microstructure, mechanical properties, corrosion resistance and fatigue strength of the Zn-1%Mg and Zn-1%Mg-0.1%Ca alloys, processed by rotary swaging (RS). It is shown that the grain refinement leads to an increase in the strength of the alloys up to 196 ± 4 and 218 ± 6 MPa for the Zn-1%Mg and Zn-1%...

The potential medical Zn-1.7%Mg and Zn-1.7%Mg-0.2%Zr alloys strengthened using high-pressure torsion (HPT) were investigated in this work. HPT led to a significant refinement of the microstructure of both alloys with the formation of an ultrafine-grained structure (UFG). The average grain size after HPT was ~700–800 nm for both alloys. The formatio...

The article discusses the solidification and phase composition of the (wt.%) Mg–4.8Gd–2.1Nd–1.6Y–0.4Zn–0.6Zr (GEWZ522K) casting alloy. It is demonstrated that in the as-cast state, the alloy structure comprises primary zirconium particles, dendrites of the magnesium solid solution (αMg), and eutectic intermetallic phases located between dendritic b...

Three-high screw-rolling of aluminum alloy ingots was carried out at 12- and 20-degrees rolls feed angles. The ingots had two copper, cylindrical inserts oriented along the ingot axis: the center of one insert coincided with the ingot’s center, and the center of the other insert coincided with the ingot’s half-radius. The effect of the rolls feed a...

In the investment casting process, the pattern made of wax is obtained in a die for further formation of a shell mold. The problem of die-filling by pattern wax is significant because it influences the quality of the final casting. This work investigates three commercial pattern waxes’ fluidity with a newly developed injection fluidity test. It was...

A study of microstructure, phase composition, mechanical properties, corrosion processes, and biocompatibility in vitro of the Zn–1%Mg and Zn–1%Mg–0.1%Ca alloys in an annealed state and after rotary swaging (RS) is presented. Partially recrystallized microstructure is formed in the studied alloys after RS at 200 °C. RS reduces the mass fraction of...

In the investment casting process, the pattern made of wax is obtained in a die for further formation of shell mold. This work investigates commercial pattern waxes fluidity with a newly developed injection fluidity test. A good correlation between wax fluidity and its viscosity is observed, which is different from metallic alloys, where the solidi...

The utilization of computer simulation software for casting process simulation is becoming essential in the advancement of casting technology in aviation and other high-tech engineering fields. With the increase in the number of computational cores in modern CPUs, the use of multi-threaded computations is becoming increasingly relevant. In this stu...

The quality of cast parts produced by investment casting is largely determined by the quality of the ceramic molds. Currently, aircraft and engine building enterprises are switching to an environmentally friendly colloidal silica binders for the manufacture of ceramic molds. In this work, the dynamic and relative viscosity of slurries prepared usin...

Magnesium alloys are usually considered as structural materials when the weight reduction is important - in aircraft and space industry for example. In recent years, there has been an increase in the use of new generation ignition-proof high-strength magnesium alloys in the design of aircraft parts. The properties of new ignition-proof casting magn...

The effect of high-pressure torsion (HPT) on the microstructure, phase composition, mechanical characteristics, degradation rate, and bioactive properties of the Zn–1%Mg alloy is studied. An ultrafine-grained (UFG) structure with an average grain size of α-Zn equal to 890 ± 26 nm and grains and subgrains of the Mg2Zn11 and MgZn2 phases with a size...

Fixation screws and other temporary magnesium alloy fixation devices are used in orthopedic practice because of their biodegradability, biocompatibility and acceptable biodegradation rates. The substitution of dissolving implant by tissues during the healing process is one of the main requirements for biodegradable implants. Previously, clinical te...

The effect of the microstructure of Zn-1% Mg and Zn-1% Mg-0.1% Ca alloys after treatment under various conditions (casting, annealing, aging) on their mechanical and corrosion properties has been studied. The addition of calcium is shown not to degrade the strength and corrosion properties of the Zn-1% Mg alloy. The change in the microstructure of...

A study of the effect of high-pressure torsion (HPT) on the structure, phase composition, corrosion resistance, mechanical properties and bioactivity in vitro of Zn-1%Mg-0.1%Ca alloy was performed. It was shown that HPT leads to refinement of the alloy microstructure with the formation of recrystallized α-Zn grains with an average size of 750 ± 30...

Magnesium alloys are attractive candidates for use as temporary fixation devices in osteosynthesis because they have a density and Young’s modulus similar to those of cortical bone. One of the main requirements for biodegradable implants is its substitution by tissues during the healing process. In this article, the Mg–Zn–Ga–(Y) alloys were investi...

This work studied the effects of adding Zr and Mn in amounts less than 1wt% on the microstructure, mechanical properties, casting properties, and corrosion resistance of Mg—Zn—Cu alloys containing 2.5wt% Cu and 2.5wt%—6.5wt% Zn. The hardness and electrical conductivity measurements were used to find an optimal heat treatment schedule with the best...

Nowadays, aluminum alloys with silicon are the most widespread construction materials. To increase the mechanical properties of aluminum alloys, modifying by Sr, Ti, and B are used. However, in the foundries, when using scrap and secondary aluminum alloys, the modifying elements are accumulated in alloys in the form of intermetallic particles that...

In magnesium alloys castings, the casting defects such as shrinkage porosity are often occur. Such defects can be suppressed by repair welding or surfacing using a special filler rod. Unfortunately, in Russia, the low amount of filler rod is consumed. Therefore, native enterprises do not manufacture it, limiting themselves to imports or homemade lo...

For simulations of misrun formations in castings, the critical fraction solid (FScr) at which the melt flow stopped in the mold is required. In this work, FScr for Al–Si alloys was obtained by comparing the simulated spiral fluidity test lengths at different FScr values with experimental ones casted into graphite and sand molds. The dendrite cohere...

Mg alloys have mechanical properties similar to those of human bones, and have been studied extensively because of their potential use in biodegradable medical implants. In this study, the influence of different heat treatment regimens on the microstructure and mechanical and corrosion properties of biodegradable Mg–Zn–Ga alloys was investigated, b...

Billets made of bronze Br010S2N3 are usually produced using a permanent mold casting technique with a low product yield. Properties of the bars 25 mm in diameter obtained using an upcasting method with different casting rates (from 120 to 280 mm/min) are investigated in the present work. It is shown that with increase in casting rate the amount of...

Magnesium alloys are used in aircraft because of their light weight. However, for these alloys to be applied in electronic devices, high thermal conductivities are required. Several high-potential compositions of Mg–Zn–Y–Zr alloys were selected by phase composition and their freezing ranges calculated using Thermo-Calc software. The alloys were pre...

The production of various housings of the units operating under the pressure of liquids or gases requires the use of alloys with increased soundness after casting. We compare the properties of the magnesium alloys most widely used for producing leakproof castings, namely, ML10, Elektron 21, EZ33A, ZE41A, and ZE63A. For each of them, the equilibrium...

In mechanical engineering, the antifriction tin bronzes, and C92900 bronze for instance are used for parts subjected to wear. The permanent mold casting into steel molds are commonly used to produce parts from C92900 bronze. This work investigates the possibility of C92900 bronze rods production by hot extrusion and upcasting methods. It has been d...

The Mg-Zn-Y-Zr alloys with long-period stacking-ordered (LPSO) and W eutectic phases were investigated to develop new magnesium casting alloys. The temperatures for T6 heat treatment were selected based on the hardness and electrical conductivity measurements. The hot tearing susceptibility of the alloys with LPSO phase is lower than that of the al...

In the mechanical engineering, antifriction tin bronzes are used for the manufacture of friction parts. For example, the C92900 bronze has found use in aircraft braking system components. One of the ways to improve the properties of leaded tin bronzes is to increase the cooling rate during solidification. This paper studies the effect of the coolin...

Magnesium alloys are used in aircraft because of their light weight. However, for these alloys to be applied in electronic devices, high thermal conductivities are required. Several high-potential compositions of Mg–Zn–Y–Zr alloys were selected by phase composition and their freezing ranges calculated using Thermo-Calc software. The alloys were pre...

Biodegradable Mg-based implants are widely used in clinical applications because they exhibit mechanical properties comparable to those of human bone and require no revision surgery for their removal. Among Mg-based alloys, Mg–Zn–Ca–(Mn) alloys have been extensively investigated for medical applications because the constituent elements of these all...

Rotary swaging (RS) of alloy Mg–1.03Zn–0.66Ca (ZX11) was shown to refine the average grain size to 4.5 ± 1.2 µm in a longitudinal section and 4.8 ± 0.9 µm in a transverse section. In addition, a small amount of Mg2Ca particles about 300 nm in size and Mg6Zn3Ca2 particles with a size of about 100 nm was detected. This resulted in pronounced strength...

Many types of alloys can be cast in graphite molds. The advantage of using graphite molds is that graphite has a higher thermal conductivity than steel and provides a higher alloy cooling rate. In this work, the solidification conditions in graphite and steel molds are compared. Cylindrical ingots of A356 aluminum and AZ81 magnesium alloys were cas...

In recent years magnesium alloys have been studied intensively with a view to their potential use in bioresorbable medical implants. In the present work the microstructure and the corrosion properties of a new bioresorbable Mg-4 wt% Ga-4 wt% Zn alloy and its variants with low Ca, Nd or Y additions were investigated. These alloys are of interest due...

In recent decades, jewelry manufacturers have started using nonprecious alloys to decrease production costs. A large number of customers, however, have an allergic (sensitizing) body reaction to jewelries made of such materials. The application of nonsensitizing coatings can decrease the negative influence of the jewelry material on the human organ...

Magnesium alloys are commonly used to produce lightweight parts. While most magnesium alloys exhibit low thermal conductivities, high thermal conductivities are needed for electronic devices. In this study, we attempted to develop new magnesium casting alloys with high thermal conductivities. The MgZnSiCa alloy compositions were chosen using CALPHA...

The influence of the addition of 2.3 at.-% Y and of 0.8 at.-% Zr + 0.2 at.-% Y on the properties of TiAl43Nb4Mo1B0.1 (TNM-B1) titanium aluminide alloy is investigated. Energy-dispersive X-ray spectroscopy analysis shows that the Y content of the β, γ, and α2 phases is low, and nearly all of the Y is in the Al2Y phase. The Zr content in the alloy ph...

The most currently widespread method of flux-free melting of magnesium alloys is melting under a protective gas atmosphere consisting of inert carrier gas with a small additive of active gas. The ML19 (Mg–Nd–Y–Zn–Zr) casting magnesium alloy contains yttrium and neodymium; these metals are rather active. The interaction of similar alloys with protec...

Currently the most common method of the magnesium alloys flux free melting is the melting under the gas protective atmosphere. This atmosphere consists of inert carrier gas with low addition of active gas. The ML19 casting magnesium alloy contains Y and Nd that enough active. The interaction of such alloys with gas protective atmospheres is poorly...

Recent decades jewelry manufacturers put into practice using of non-precious alloys in order to decrease the production costs. Nevertheless, the large number of customers has allergic (sensitizing) body reaction on jewelries. Applying of non-sensitizing coating is able to decrease negative influence of jewelry material on human body. One of the bio...

Steel is one of the widespread materials for producing of permanent molds for aluminium casting. At the same time the materials that can promote higher cooling rate are available. One of that type of materials is graphite. In our work the comparison of cooling conditions for A356 aluminium ingots casting with different diameters into the steel and...

The second part of the article considers influence of the scrap amount on structure and mechanical properties of ZhS6U-VI nickelbased superalloy. As the use of scrap is associated with the possibility of alloy contamination by nonmetallic inclusions and loss of alloying elements, the influence of scrap on alloy structure and mechanical properties i...

Zn is a commonly used alloying element for Mg alloys owing to its beneficial effects on mechanical properties. To improve the mechanical and corrosion properties of WE43B Mg alloys, the effects of 0–0.7wt% Zn addition on the microstructure and properties of sample alloys were investigated. Addition of Zn to as-cast WE43B alloy promoted the formatio...

The composition is developed and heat-treatment mode is determined for obtaining an intensely dissolving magnesium alloy for use as ball plugs in conditions of oil-well preparation, i.e., to seal various well sections with the subsequent and almost complete fracture of these balls in a short time (up to 11 h). It is revealed that the cause of a hig...

Expensive nickel superalloys are used for manufacture of cast blades of gas turbine engine (GTE). However, for the blades only a small amount of alloy was used and the remainder is used for gating system. Therefore, the most proportion of alloy after casting is a scrap, the use of which as raw material for blades production significantly reduces th...

Alloy composition was developed and heat treatment conditions were selected to obtain an intensively dissolving magnesium alloy to be used as a ball plug under oil-well precommissioning conditions, i.e. to seal various well sections with further near-complete destruction of these plugs for a short time (up to 11 h). It was found that the reason of...

Predicting the misrun formation in thin-walled castings of magnesium alloys is a critical task for foundry. The computer simulation of casting processes can be used to solve this problem. Adequate results of simulation can be attained in the presence of the correct thermal properties of the alloy and a mold in a wide temperature range, interface he...

Prediction of the misrun formation in thin-walled castings of magnesium alloys is a crucial task for foundry. The computer simulation of the casting processes can be used to solve this problem. A reasonable simulation results requires the correct thermal properties of the alloy and the mold over a wide range of temperatures and the value of interfa...

The Mg - (2.2-3.8 wt. %)Zn - (0.3-0.7 wt. %)Ca – (0-0.9 wt. %)Mn alloys as a material for the production of biodegradable implants was investigated. Equal-channel angular pressing (ECAP) to improve the grain structure and mechanical properties of the alloys was used. The microstructure and phase composition of alloys were determined using scanning...

We investigate the new alloys of Mg-Ga-Zn-X system, where X = Ca, Y and Nd. These alloys can be used as biodegradable materials due to the low cytotoxicity of Zn and Ga and effectiveness of Ga against bone resorption, osteoporosis and Paget’s disease. The microstructure and phase composition of alloys were determined using scanning electron microsc...

We investigate the new alloys of Mg-Ga-Zn-X system, where X = Ca, Y and Nd. These alloys can be used as biodegradable materials due to the low cytotoxicity of Zn and Ga and effectiveness of Ga against bone resorption, osteoporosis and Paget’s disease. The microstructure and phase composition of alloys were determined using scanning electron microsc...

This paper examines the ZK51A (ML12) alloy samples with content of Zn from 3,5 to 5,5 wt. % and Zr from 0,5 to 0,8 wt. %. The influence of the Zn and Zr content on the phase transition temperatures and the phase composition in equilibrium conditions and by the Scheil-Gulliver solidification model was determined using the calculation in a Thermo-Cal...

The objects of investigation are ZK51A (ML12) alloy samples containing from 3.5 to 5.5 wt % Zn and 0.5–0.8 wt % Zr. The influence of Zn and Zr content on phase transition temperatures and the phase composition in equilibrium conditions and when using the Scheil–Gulliver solidification model is established using the calculation of phase diagrams in...

Samples of ML19 magnesium alloy with composition, wt %, (0.1–0.6)Zn–(0.4–1.0)Zr–(1.6–2.3)Nd–(1.4–2.2)Y have been investigated. The influence of Nd, Y, Zn, and Zr on equilibrium phase-transition temperatures and phase composition using Thermo-Calc software is established. The Scheil–Gulliver solidification model is also used. We show the significant...

The basic parameters for the high-precision simulation of misrun formation in castings are the interface heat transfer coefficient (IHTC) between the casting and the mold and the critical solid fraction (fScr) at which the alloy flow in the mold is choked off. The values for IHTC were obtained by comparing the simulated spiral lengths at different...

Alloys of the Mg – Zn – Zr – Nd system with composition matching that of ML10 (NZ30K) and different contents of the main alloying components within the standardized range are studied. Four-component Mg – Zn –Zr – Nd phase diagrams are simulated, and the stages of crystallization of the alloys are considered. The structure of the alloys is determine...

The effect of iron impurity on the structure and properties of aluminum alloy AL9M, especially its action on magnesium distribution within the structure, is studied. The microstructure of a cast component of this alloy broken during operation is analyzed. It is shown that iron impurity has an unfavorable effect on structure and mechanical propertie...

The mechanical properties of castings depend on the grain size. There is evidence that titanium and boron (Al-5Ti-1B master alloy) affect the grain size of magnesium alloys. Here, the influence of the addition of 0-1 wt. % of Al-5Ti-1B master alloy on the grain size of AZ91 magnesium alloy was investigated. Melting of the alloy was performed in ste...

In order to determine the temperature gradients in ingots fabricated by the directional solidification (DS) using an UVNS-6 installation produced by VIAM (Moscow), single-crystalline ingots made of VZhM3 nickel superalloy have been prepared. Herewith, DS technologies with liquid-metal cooling (LMC) and without it are used (the Bridgman–Stockbarger...

It is necessary to know the interface heat transfer coefficient (iHTC) between the casting and the mold for the simulation of casting filling and solidification processes in the casting simulation software systems. This study demonstrates the way we determined the heat transfer coefficient h between the cylindrical casting of 50-56 mm in diameter a...

The ML10 (NZ30K) magnesium alloy is usually melted from MZr1N3 (bal. Mg, 1wt.% Zr, 3wt.% Nd) by adding Mg - 15wt.%Zr (L2 or L4), Mg -20wt.%Nd (MN) master alloys and pure zinc. Solikamsk Experimental Magnesium Plant was the first manufacturer of magnesium alloys that offered the ML10 alloy ingots on the Russian market. Two samples of the ML10 alloy,...

To produce castings of titanium, nickel, copper, aluminum, and zinc alloys, graphite molds can be used, which makes it possible to provide a high cooling rate. No die coating and lubricant are required in this case. Computer simulation of casting into graphite molds requires knowledge of the thermal properties of the poured alloy and graphite. In a...

Pulverbakelite (solid novolac phenol-formaldehyde resins with hexamine additive) and bakelite varnish (solution in alcohol resole resin) glue composites containing graphite powder filler have been studied for bonding and repair of mold elements that are used in the model-free fabrication of titanium alloys. A composite I (G42P32S26) with 32 wt % of...

Graphite molds can be used to produce titanium, nickel, copper, aluminum and zinc castings. Using of the graphite molds provides a high cooling rate. Moreover no die coatings and lubricants are required. To get appropriate results of the casting process simulation in graphite molds it is necessary to know thermophysical properties of materials and...

The heat-transfer coefficient h between a cylindrical cast made of AK7ch (A356) aluminum alloy and a no-bake mold based on a furan binder is determined via minimizing the error function, which reflects the difference between the experimental and calculated temperatures in the mold during pouring, solidification, and cooling. The heat-transfer coeff...

The influence of the calcium additive (from 0.1 to 1.0 wt %) on the phase composition and solidus temperature of ML5 magnesium alloy is investigated. Calcium transfers into the intermetallic compound of the variable composition during alloy crystallization. This compound contains Al (53.4–57.4%), Ca (42.6–42.8%), and Mg (0.002–3.8%) and is transfor...

The influence of calcium additives (from 0,1 to 1,0 wt.%) on the phase composition and the solidus temperature of ML5 magnesium alloy was studied. During the alloy crystallization in the presence of aluminum, calcium forms an intermetallic compound with a variable composition containing Al (53,4–57,4 %), Ca (42,6–42,8 %) and Mg (0,002–3,8 %). As th...

Determined the iHTC (interface Heat Transfer Coefficient) between AK7ch (A356) aluminum alloy casting and no-bake mold. The heat transfer coefficient is determined by minimizing the error function values, representing the difference between the experimental and calculated temperature in the mold values during pouring, solidification and cooling. De...

The process of crystallization of Mg - 6.3% Al - 3.7% Ca - 0.3% Mn and Mg - 4.5% Al - 2% Ca - 0.5% Mn alloys was considered with application of modeling of the state diagram Mg - Al - Ca - Mn in the Thermo-Calc program. Their phase content in equilibrium conditions was researched. There was made a definition that both alloys are crystallized in the...

This article considers the issues, associated with obtaining of thin-dimensional castings of titanium alloy by precision casting into shell molds. There were observed the peculiarities of computer simulation of casting and solidification using ProCast program. Liquidus and solidus temperatures of the VT20L (BT20?) alloy were updated on the basis of...

Properties of the TNM-B1 γ-titanium aluminide alloy are investigated in order to find reliable results of a simulation of casting processes used to produce the blades of gas-turbine aircraft engines. Thermal properties of the TNM-B1 alloy are experimentally determined using the methods of differential scanning calorimetry (DSC), laser flash analysi...

Properties of the TNM-B1 alloy based on γ-titanium aluminide are investigated in order to find reliable results of simulation of casting processes used to fabricate the blades of gas-turbine aircraft engines. Thermal properties of the TNM-B1 alloy are experimentally determined using the methods of differential scanning calorimetry (DSC), laser flas...

The opportunity to simulate the process of titanium aluminide based TNM-B1 alloy casting production according to ProCast program is considered. Comparison of crystallization parameters obtained by means of ProCast and Thermo-Calc thermo-dynamic bases is made. The alloys available in ProCast base are shown to be more preferable for simulation. An es...

A rapidly cooled Mg – Zr addition alloy is obtained by remelting a commercial L-4 addition alloy and crystal-lizing the latter at elevated cooling rates. The possible phase transformations are analyzed on the basis of frag-ments of an equilibrium Mg – Zr phase diagram plotted with the use of the Thermo-Calc software. The pro-cess of segregation of...