Single-phase State Research Articles

Magnetic hysteresis of Sm1-x Gdx Co3 Cu2 alloys

The paper presents the results of a comprehensive study of the hysteresis characteristics of Sm1−𝑥Gd𝑥Co3Cu2 alloys (x=0.1–0.9), considering their actual microstructure. It is shown that in the as-cast state, all alloys in the series are significantly heterogeneous and contain inclusions of up to three phase components. Hightemperature annealing at 1050∘C for 4 hours enables modifying the microstructure of the original alloys, however, a single-phase state was only achieved for alloy samples with 𝑥 = 0.1. The high-coercivity state of the samples is provided by a regular microstructure and is implemented through the pinning mechanism. The maximum coercive force of 0.94 T was achieved on the Sm0.4Gd0.6Co3Cu2

Flow boiling in a rectangular micro/mini channel with self-rewetting and non-rewetting fluids

In this experimental investigation the influence of self-rewetting during flow boiling was studied in a horizontal microchannel during one-sided uniform heating. The channel had a width and height of 6 mm and 0.3 mm respectively. Local wall temperature and direct in-time flow visualisation was performed. The working fluids under consideration included water as base reference, pure 1-butanol, pure ethanol, dilute butanol-water self-rewetting mixtures, and a dilute ethanol-water binary mixture. Tests were conducted at mass fluxes of 10, 15 and 25 kg/m2s, over a range of heat fluxes to produce both single phase and two-phase quasi steady state flow data. Within the wall temperature ranges of interest, the butanol-water mixtures (5 % and 7 % by volume butanol) had surface tension characteristics that would draw liquid toward local wall hotspots. Local and average wall temperatures and heat transfer coefficients were obtained and considered against the governing flow pattern visualisations. In contrast to the other fluids, the self-rewetting butanol-water mixtures exhibited significantly more stable flow and more predictable saturation flow boiling heat transfer coefficient trends across all heat fluxes under consideration. At the lowest mass flux, it was found that an increase in the heat flux resulted in an improvement in the self-rewetting fluids heat transfer performance, while at higher mass fluxes this dependence was diminished. Across all mass fluxes and heat fluxes the 5 % butanol-water outperformed its 7 % butanol-water counterpart. The tendency of self-rewetting to reduce local dry-out, even at low mass fluxes are demonstrated.

Micro-encapsulated phase change material suspensions for heat and mass transfer: A thermo-physical characterization

Despite the growing popularity of phase change materials (PCM) and suspensions of micro-encapsulated phase change materials (mPCM) in both industrial and scientific applications, their properties characterization remains partial and mainly limited to thermal properties. The characterization of such suspension is a crucial aspect for comprehending their behavior and optimizing their performance. This paper is dedicated to a wide characterization of two suspensions containing micro-encapsulated phase change material. In pursuit of a thorough understanding, we also extend our characterization efforts to the bulk PCM encapsulated within the particles.Our primary focus is on determining the materials thermal properties such as latent heat and specific heat capacity using differential scanning calorimetry. Different cooling and heating rates have been employed in our measurements. Regarding our experiments, the bulk phase change material is predominantly identified as octadecane. Results obtained from calorimetry are then compared between the bulk PCM and the mPCM suspensions. By comparing the magnitudes of latent heat obtained for suspensions with the bulk material, we can accurately determine the mass fraction of PCM within each suspension. Noteworthy, during the solidification process an additional latent heat peak is observed only for the encapsulated PCM.The density of the materials is also measured. The phase change of PCM included in the capsules can be observed in densimetry: within the studied temperature range (283.15–306.15 K), the most significant density variations occur during intervals associated with phase change transitions. In ranges where the PCM, included in the capsules, is in a single-phase state (solid/liquid), we provide linear laws that account for density variations with temperature.Finally, our characterization work focuses on the rheological properties of the materials. While the bulk PCM in liquid phase exhibits a Newtonian viscosity, mPCM suspensions present a non-Newtonian viscosity. Both shear-thinning and shear-thickening behaviors are observed depending on the suspension particle volume fraction ϕ of mPCM. This paper concludes with a full comparison of our characterization results with models and correlations proposed in the literature.

Effects of non-equilibrium phase behavior in nanopores on multi-component transport during CO2 injection into shale oil reservoir

Injecting CO2 into shale oil reservoirs is one of the most effective methods for enhancing oil recovery (EOR) while simultaneously facilitating CO2 capture, utilization, and storage (CCUS). However, it is not always that gas dissolution or condensate evaporation reaches equilibrium instantaneously during the CO2 injection process. In cases where equilibrium is not attained instantaneously, conventional vapor-liquid equilibrium models will have certain limitations in characterizing phase transition hysteresis. These limitations will affect the accuracy of simulating multi-component transport in porous media. In this paper, a robust and generic vapor-liquid non-equilibrium thermodynamic model considering nano-confinement effects (NC) was established by introducing component mass transfer rates proportional to the chemical potential difference. The established model was then used to modify the fully-compositional, projection-based embedded discrete fracture model (pEDFM). Furthermore, C++ hybrid programming and the Graphics Processing Unit (GPU) parallel method were both used to accelerate both the nonlinear and linear solvers. By comparing with results from MATLAB Reservoir Simulation Tools (MRST), Eclipse, and tNavigator, the accuracy and advantages of our solver were demonstrated. The results show that if the underground fluid undergoes a phase transition from a vapor-liquid two-phase state to a single-phase state, non-equilibrium thermodynamic effects need to be considered, and the simulation results show a larger two-phase zone, higher bottom hole pressure, and lower cumulative liquid production. But the nano-confinement effects will weaken the non-equilibrium thermodynamic effects.

A New Non-Extensive Equation of State for the Fluid Phases of Argon, Including the Metastable States, from the Melting Line to 2300 K and 50 GPa

A new equation of state for argon was developed with the view of extending the range of validity of the equation of state previously proposed by Tegeler et al. and obtaining a better physical description of the experimental thermodynamic data for the whole fluid region (single-phase, metastable, and saturation states). As proposed by Tegeler et al., this equation is also based on a functional form of the residual part of the reduced Helmholtz free energy. However, in this work, the fundamental equation for Helmholtz free energy was derived from the measured quantities CV(ρ, T) and P(ρ, T). The empirical description of the isochoric heat capacity CV(ρ, T) was based on an original empirical description explicitly containing the metastable states. The thermodynamic properties (internal energy, entropy, and free energy) were then obtained by combining the integration of CV(ρ, T). The arbitrary functions introduced by the integration process were deduced from a comparison between calculated and experimental pressure P(ρ, T) data. The new formulation is valid for the whole fluid region from the melting line to 2300 K and for pressures up to 50 GPa. It also predicts the existence of a maximum of the isochoric heat capacity CV along isochors, as experimentally observed in several other fluids. For many applications, an approximate form of the equation of state for the liquid phase may be sufficient. A Tait–Tammann equation is therefore proposed between the triple-point temperature and 148 K.

Experimental investigation of the intermittent spray heat transfer characteristics of nanofluids in single- and two-phase states

Traditional air-cooled cooling systems used in engineering vehicles consume significant energy and do not align well with future development trends. To address this problem, a single- and two-phase intermittent spray cooling technique for nanofluids was proposed in this study. The effects of the duty cycle and spray frequency on the heat transfer performance and surface temperature uniformity of intermittent spray were determined by experiments, and the thermal behaviour of intermittent spray with different mass fractions of Al2O3 nanofluids was compared in detail. The results revealed that when the spray frequency is constant, the heat transfer coefficient increases with an increase in duty cycle, but the cooling efficiency decreases. The spray frequency mainly affects the average heat transfer surface temperature and its uniformity. At 2.0 Hz, nanofluids with a mass fraction of 0.7 % exhibited the best intermittent spray performance, with an average heat transfer coefficient of 431.8 W/(m2·K). However, a continuous increase in the mass fraction of the nanofluids inhibited the heat transfer performance. The impact of droplets on the heat transfer surface, the liquid film heat transfer process, and the heat transfer characteristics of the nanofluid intermittent spray in the single- and two-phase states were further studied. The results revealed that the heat transfer of intermittent spray mainly depends on the properties and flow rate of the coolant in a single-phase state. Although the heat transfer performance of intermittent spray is evidently enhanced in the two-phase state, it still does not exceed that of continuous spray. These findings highlight the flexibility of nanofluid intermittent spray cooling in enhancing heat transfer control and can inform the development of energy-saving and intelligent cooling systems for engineering vehicles.

Efficient access to ultrafine crystalline metastable-β titanium alloy via dual-phase recrystallization competition

In order to reduce the deformation resistance, the rolling process of metastable β titanium alloys is generally carried out in the β single-phase state, which causes the problem of non-uniform grain size during the subsequent annealing process, thus affecting the alloy properties. Here we first solution-treated the as-cast Ti–15Mo–3Al-2.7Nb-0.2Si alloy at 740 °C to obtain α + β phase, then cold rolled it with a reduction of 60 %, and finally annealed it at 710–810 °C for 2–240min. Characterization of the annealed metastable β alloy revealed that α phase was involved in the rolling deformation at the same time and recrystallized on the β matrix during the subsequent annealing process, known as equiaxial dispersion, which impeded the recrystallization of the β grains, and ultimately an ultrafine crystalline microstructure of α + β phases with an average grain size of less than 2 μm was obtained.

In situ adaptive tabulation of vapor-liquid equilibrium solutions for multi-component high-pressure transcritical flows with phase change

Vapor-liquid equilibrium (VLE) is a family of first-principled thermodynamic models for transcritical multiphase flows, which can accurately capture the phase transitions at high-pressure conditions that are difficult to deal with using other models. However, VLE-based computational fluid dynamics (CFD) simulation is computationally very expensive for multi-component systems, which severely limits its applications to real-world systems. In this work, we developed a new ISAT-VLE method based on the in situ adaptive tabulation (ISAT) method to improve the computational efficiency of VLE-based CFD simulation with reduced memory usage. We developed several ISAT-VLE solvers for both fully conservative (FC) and double flux (DF) schemes. New methods are proposed to delete redundant records in the ISAT-VLE table and the ISAT-VLE method performance is further improved. To improve the convergence of the VLE solvers, a modified initial guess for equilibrium constant is also introduced. Simulations of high-pressure transcritical two-phase temporal mixing layers and shock-droplet interaction were conducted using the ISAT-VLE CFD solvers. The simulation results show that the new method obtains a speed-up factor approximately from 10 to 60 and the ISAT errors can be controlled within 1%. The shock-droplet interaction results show that the DF scheme can achieve a higher speed-up factor than the FC scheme. The two sets of simulations exhibit the phase separation at high-pressure conditions. It was found that even at supercritical pressures with respect to each component, the droplet surface could still be in a subcritical two-phase state, because the mixture critical pressure is often significantly higher than each component and hence triggers phase separation. In addition, a shock wave could partially or completely convert the droplet surface from a subcritical two-phase state to a single-phase state by raising temperature and pressure.

Phase characteristics modeling of reservoir gas-condensate mixture of Tegermen group of fields

Taking into account the forthcoming concept, it is proposed to develop Tegermen group of fields with construction of onshore systems for collection, treatment and transportation of natural gas in order to supply the extracted products to the gas treatment point (Samantepe gas treatment unit-2) in a single-phase state. Natural hydrocarbon systems consist of a large number of components, and these are not only hydrocarbons of the paraffin series, but also hydrocarbons belonging to other groups. The phase state of a hydrocarbon mixture depends on its composition, as well as on the properties of individual components. Construction in a wide range of temperature and pressure values of phase diagrams of reservoir fluids with low condensate factor allows to determine with high accuracy the parameters of the beginning of condensate precipitation (dew point) in the system of gas gathering and transportation to supply the produced products of Tegermen group of fields.

Crystal structure of solid solutions 0.65BiFeO3–0.35Ba1-xSrxTiO3 in the region of morphotropic phase boundary

Solid solutions 0.65BiFeO3–0.35Ba1-xSrxTiO3 (0 ≤ x ≤ 1) with the compositions in the vicinity of the morphotropic phase boundary “rhombohedral-cubic” were synthesized by the Solid-state reaction method. The crystal structure and morphology of the ceramics 0.65BiFeO3–0.35Ba1-xSrxTiO3 were studied based on the data obtained by X-ray diffraction, scanning electron microscopy, Raman spectroscopy, as well as energy-dispersive X-ray spectroscopy methods. It was determined that the chemical substitution of barium ions with strontium ions leads to a decrease in the magnitude of rhombohedral distortions, while the unit cell parameters decrease in the whole substitution concentration range. The solid solutions with x ≥ 0.25 are characterized by a single-phase structural state with a cubic unit cell; the average crystallite size decreases with increase of the dopant ions. The results of the structural studies carried out using Raman spectroscopy indicate the presence of rhombohedral distortions in the structure of all studied compounds, which is caused by the presence of nanosized clusters with rhombohedral symmetry. The obtained results made it possible to determine the sequence of the changes occurred in the phase state and the unit cell parameters in the region of the morphotropic phase boundary “rhombohedral -pseudocubic”; the concentration intervals corresponding to the single-phase and two-phase structural states of the compounds were determined. The region of concentration stability of the polar rhombohedral phase was clarified using the structural data obtained by local and microscopic research methods.

Magnetization reversal processes of nanostructured PrFeB alloys

The paper considers the high-coercivity state of the melt-spun PrFeB alloys with different phase composition: the main Pr2Fe14B phase grains separated by the paramagnetic layers, single-phase state (Pr2Fe14B grains only), and combination of Pr2Fe14B and α-Fe phase grains. The phase composition and microstructure of the alloys, as well as their magnetic properties in the temperature range of 2–300 K are given. To establish the prevailing mechanism of the high-coercivity state, magnetometric techniques were used, including the study of the reversible magnetic susceptibility, and simulations by the finite difference method. The simulations of the magnetization reversal of these alloys demonstrate the complexity of this processes, which go beyond simple nucleation or pinning, and cannot be described in the framework of the Kneller-Hawig model. Models of magnetization reversal of the alloys under study are proposed. The presence and composition of the intergranular layer has a significant effect on the mechanism of the high-coercivity state.

Development and validation of the lead-bismuth cooled reactor system code based on a fully implicit homogeneous flow model

The liquid lead-bismuth cooled fast reactor has been in a single-phase, low-pressure, and high-temperature state for a long time during operation. Considering the requirement of calculation efficiency for long-term transient accident calculation, based on a homogeneous hydrodynamic model, one-dimensional heat conduction model, coolant flow and heat transfer model, neutron kinetics model, coolant and material properties model, this study used the fully implicit difference scheme algorithm of the convection-diffusion term to solve the basic conservation equation, to develop the transient analysis program NUSOL-LMR 2.0 for the lead-bismuth fast reactor system. The steady-state and typical design basis accidents (including reactivity introduction, loss of flow caused by main pump idling, excessive cooling, and plant power outage accidents) for the ABR have been analyzed. The results are compared with the international system analysis software ATHENA. The results indicate that the developed program can stably, accurately, and efficiently predict the transient accident response and safety characteristics of the lead-bismuth fast reactor system.

PHASE EQUILIBRIA IN THE Li–Mn–Eu–O SYSTEM

Phase equilibria in the Li–Mn–Eu–O system were studied for the first time in the temperature range 700–1000°С, and a concentration diagram was plotted within the Li–Mn–Eu triangle at an oxygen partial pressure of 21 kPa. It is shown that the LiEuO2–Li2MnO3 system is quasi-binary, unlike the sections LiEuO2–LiMnO2 and LiEuO2–LiMn2O4. It has been established that, for spinel LiMn2O4 (Fd\(\bar {3}\)m), a homogeneous introduction of 2 mol % Eu is possible, while in the case of Li2MnO3 (C2/m), the single-phase state decays.

Dependence of Electrochemical Characteristics of a Biodegradable Fe-30Mn-5Si wt.% Alloy on Compressive Deformation in a Wide Temperature Range

Fe-30Mn-5Si alloy subjected to a compression test at various deformation temperatures ranging from 350 to 900 °C with a strain rate of 1 s−1 are studied. It was found that the Fe-30Mn-5Si alloy exhibits high resistance to the dynamic recrystallization process in a whole studied range of deformation temperatures. There are no differences in structure formation in the zone of action of tangential tensile stresses and peripheral and central zones of localized compressive stresses. The room-temperature X-ray diffraction study shows the presence of a single-phase state (FCC γ-austenite) after deformation temperature range from 350 to 700 °C and a two-phase state (FCC γ-austenite + HCP ε-martensite) after deformation test at 900 °C. The presence of a two-phase state provides a higher rate of biodegradation compared with a single-phase state. The changes in the biodegradation rate dependence on the structure change with an increase in the deformation temperature are explained. Favorable temperature regimes for subsequent thermomechanical processing are proposed based on the relationship between structure formation and biodegradation rate to obtain semi-products from the Fe-30Mn-5Si alloy.

Microstructure and properties of the GEWZ522K casting magnesium alloy based on the Mg–Gd–Nd–Y–Zn–Zr system

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 branches. Following solution heat treatment at t = 530±5 °C, the alloy transitions into a single-phase state and can be significantly strengthened through artificial aging after quenching. It is recommended to apply alloy aging at t = 250 °C for 8–10 h or at t = 200 °C for 15–18 h. This approach leads to the maximum strengthening of the alloy, with the best mechanical properties achieved for the alloy aged at t = 250 °C. Regardless of the aging method used, the ultimate tensile strength (UTS) of the samples surpasses 300 MPa, which significantly exceeds that of commercial casting alloys according to GOST 2856-79. The measured corrosion rate for the GEWZ522K alloy is 7.5±0.4 mm/year, that slightly higher than that for the less alloyed commercial alloy ML10 (approximately 2.5 mm/year) tested under similar conditions. Furthermore, the alloy was subjected to tests for ignition resistance when in contact with air. It was observed that with continuous airflow over the specimen’s surface, ignition centers appear at t = 625 °C due to the breakdown of the oxide film, causing the alloy to nearly completely melt. Therefore, the GEWZ522K alloy can be employed as a high-strength casting alloy. However, during the operation of cast parts, particular attention must be paid to safeguarding the surface of these parts against corrosion.

STRUCTURE AND MECHANICAL PROPERTIES OF Ti-Cr-Al-Nb AND Ti-Cr-Al-Nb-V MULTICOMPONENT ALLOYS

The empirical and semi-empirical models were used to analyze the phase-structural state of five- and fourcomponent alloys of the Ti-Cr-Al-Nb-V system. Two compositions of lightweight alloys were selected for experimental study: Ti60Cr11Al7Nb11V11 and Ti60Cr11Al7Nb22 (at. %). Ingots of these alloys were obtained by argonarc melting method, and they were subjected to homogenization, deformation by rolling and subsequent annealing at different temperatures. The influence of annealing temperature on the phase-structural state of the alloys, their hardness, and mechanical properties during tensile tests has been studied experimentally. It was found that the change of phase composition and grain size during annealing in the temperature range of 700…900 ºC practically does not affect the hardness and tensile strength of alloys. Annealing at 900 ºC transforms the alloys into a singlephase state with bcc lattice and significantly increases the elongation to fracture, which is about 30% for both alloys. In addition, the yield strength and tensile strength of the five-component alloy are noticeably higher than those of the four-component alloy.

Correlation of the chemical composition, phase content, structural characteristics and magnetic properties of the Bi-substituted M-type hexaferrites

Bi-substituted M-type hexaferrites, BaFe12-xBixO19 (0.1 ≤ x ≤ 1.2), or Bi-BaM, were produced by the solid-state reactions. The correlation between the phase content, chemical composition, crystal structure features, and peculiarities of the magnetic properties of Bi-BaM was established using XRD (X-ray diffraction), SEM (scanning electron microscopy), and VSM (vibrational sample magnetometry). XRD phase analysis made it possible to establish the limit of substitution of Fe3+ ions by Bi3+ ions. It was shown that at a low substitution level (x ≤ 0.3), no impurity phases were detected, and the samples are characterized by a single-phase state with the space group (SG) P63/mmc. As the degree of substitution (x ≥ 0.6) increases, the formation of impurity phases was observed, which can be explained by the difficulties of ion diffusion in the process of solid-phase synthesis as well as the formation of defects in the magnetoplumbite structure due to the large ionic radius of Bi3+. As impurity phases in the studied compositions (x ≥ 0.6) the following were noted: BiFeO3 (SG: Pnma); BiO2 (SG: Fm-3m); BaBi2O6 (SG: R-3); and Ba0.5Bi1.5O2.16 (SG: Im-3m). The content of the main phase (SG: P63/mmc) decreases from 95.11 to 88.27 vol% with an increase in x from 0.6 to 1.2, respectively. Analysis of SEM images showed the growth of particles up to 10 μm, depending on the concentration of bismuth oxide during hexaferrite synthase. The Bi-BaM magnetic characteristics were examined using VSM in the range of 3 T at 300 K. Due to the magnetic structure's frustration, with increased x a decrease in saturation magnetization (Ms) was found. There were two concentration diapasons with different speeds of Ms decrease. In the first diapason, the main contribution belong to the magnetic structure frustration in the frame of the main phase (P63/mmc) due to the long-range Fe-O-Fe exchange interaction weakening (under Bi substitution). In the second diapason, the main contribution belong to the impurity phase formation and decrease of the main magnetic phase concentration in samples.

Crystal Structure and Magnetic Properties of Bi1-yBa(Sr)Fe1-yTiyO3 Solid Solutions

Abstract: Usages of various chemical substitution schemes of the initial multiferroic BiFeO3 can significantly reduce known drawbacks specific for the functional oxides based of iron ions and thus foster a creation of novel magnetoelectric compounds perspective for various technological applications. In the present study the co-doped compounds of the system Bi1-y(Ba1- xSrx)yFe1-yTiyO3 (x = 0.0 – 1.0; y ≤ 0.4) synthesized using sol-gel technique were analyzed focusing on the crystal structure stability and the correlation between the structure and magnetic properties. The concentration driven evolution of the crystal structure as well as the unit cell parameters were investigated based on the X-ray diffraction data, the correlation between the crystal structure and the magnetic properties of the compounds has been studied by magnetometry techniques. The compounds Bi1-y(Ba1- xSrx)yFe1-yTiyO3 with x = 0; y = ≤ 0.2 are characterized by single-phase rhombohedral structure, and increase in the dopant concentration to y = 0.4 leads to the stabilization of the pseudocubic phase. An increase in the Sr content leads to the phase transition in the compounds to the single phase state with the cubic structure which is accompanied by an increase in the value of the remanent magnetization.

Study on the effect of solution treatment on mechanical and corrosion properties of SAF 2507DSS produced by LPBF

In recent years, the application of Laser powder bed fusion (LPBF) technology in the manufacturing industry has become increasingly widespread. Compared to traditional casting processes, LPBF technology allows for the production of complex-shaped and structurally unique components made of 2507 duplex stainless steel (2507DSS), thus improving production efficiency and product quality. This article focuses on determining the LPBF parameters required for printing 2507DSS, successfully fabricating samples with a density of 98.71% and subjecting them to solution treatment followed by tensile testing. The results show that the LPBF-prepared samples exhibit a strength of 1173 MPa and an elongation of 18%. The presence of island-like structures enables excellent mechanical performance in the horizontal direction. The samples subjected to solution treatment at 1100 °C exhibit a strength of 860 MPa and an elongation of 45%. It is observed that when 2507DSS undergoes solution treatment from a single-phase state, the formation of large-angle grain boundaries and residual stresses within the austenite phase occurs, and a reasonable explanation is provided. Furthermore, the article conducts electrochemical tests on the samples. The results indicate that the LPBF-prepared samples possess the same electrochemical properties as the samples treated at 1100 °C, and both outperform the cast samples. Thus, this study reveals that the proportion of phases is not the sole determining factor for the corrosion resistance of DSS, providing valuable insights for the future development of more corrosion-resistant 2507DSS materials.

Structure of Ni44.4Mn36.2Sn14.9Cu4.5 alloy applicable for thermomechanical treatment

Ni-Mn-Sn Heusler alloys exhibit a significant value of magnetocaloric effect. A disadvantage of these alloys is their high brittleness in the as-cast state, but their ductility can be increased by a thermomechanical treatment. The results of a study of thermal treatment for achieving a structure of Ni44.4Mn36.2Sn14.9Cu4.5 alloy applicable for further thermomechanical treatment are presented. It is shown that after argon-arc melting and cooling of the ingot in a water-cooled copper crucible, the structure is characterized by two phases that are quite similar in composition and have no clear phase boundaries. After homogenization annealing at 860°C for 24 hours and slow cooling, a two-phase state with regions enriched in Cu atoms is observed. It is possible to preserve the single-phase structure of the high-temperature state by quenching from the annealing temperature. In order to imitate the temperature regime of thermomechanical treatment, the alloy in the single-phase quenched state was subjected to annealing at 700°C for 1 hour and slow cooling. An analysis of the microstructure shows that, as a result, it remains in the same single-phase state. Thus, a mode of heat treatment of the Ni44.4Mn36.2Sn14.9Cu4.5 alloy, which makes it possible to achieve the applicable structure for further thermomechanical treatment, was selected.