Γ-solid Solution Research Articles

NICKEL-BASED SUPERALLOYS EXPLOITATIONAL PROPERTIES RISING DUE TO THE INFLUENCE ON LATTICE PARAMETERS

Objective. It consists in establishing relationships between the chemical composition, mechanical properties, and dimensional inconsistency of crystal lattices of nickel-based superalloys. That makes it possible to reduce the volume of experimental research in the conditions of the production process and experimental developments. Research methods. The results of experimental and calculated data, formed on the basis of experimental and results taken from open sources, are given. The phase composition was determined by X-ray structural analysis using the Bragg-Brentano focusing method on a RIGAKU MINIFLEX 600 diffractometer (CoKα radiation). The experimental values were processed by the method of least squares with obtaining correlation dependencies of the “parameter-property” type and establishing mathematical equations of regression models that optimally describe these dependencies. Obtained results. It was established that with an increase in the amount of misalignment of crystal lattices, the strength of alloys decreases due to significant internal stresses. It was found that for alloys of uniform and directional crystallization, the extremum is observed at a value of 1.5...1.6 Kγ′, this is due to a decrease in the number of elements in the γ-solid solution. It is shown that the obtained dependences correspond to reality and coincide with experimental data at the level of 10 %. Scientific novelty. The value of the work lies in the fact that the dependence of the influence of alloying elements on the mechanical properties and the discrepancy in the sizes of the crystal lattices was obtained, which made it possible to determine the properties without conducting experiments. It was established that changes in the course of dependencies are closely correlated with the processes taking place in the structure of alloys. Practical value. The obtained dependencies can be used both for the development of new superalloys and for the improvement of the compositions of industrial alloys.

Effect of MBF-20 Interlayer on the Microstructure and Corrosion Behaviour of Inconel 625 Super Alloy after Diffusion Brazing.

The joining zone includes three main parts, which comprise an isothermal solidification zone (ISZ), the athermal solidification zone (ASZ), and a diffusion affected zone (DAZ). Field emission scanning electron microscopy (FESEM) was used here to observe the microstructure equipped with ultra-thin window energy dispersive X-ray spectrometer (EDS) system. Additionally, electrochemical impedance spectroscopy (EIS) and cyclic potentiodynamic polarization tests were conducted to evaluate the effect of the DB process on the corrosion resistance of the Inconel 625 superalloy. In the bonding time period, some Mo- and Cr-rich boride precipitations and Ni-rich γ-solid solution phases with hardened alloy elements, such as Mo and Cr, formed in DAZ and ASZ, respectively, because of the inter-diffusion of melting point depressants (MPD). Moreover, during cooling cycles, Ni-Cr-B, Ni-Mo-B, Ni-Si-B, and Ni-Si phase compounds were formed in the ASZ area at 1110-850 °C. The DAZ area developed by borides compound with cubic, needle, and grain boundary morphologies. The corrosion tests indicated that the DB process led to a reduction in the passive region and increased the sensitivity to pitting corrosion.

ANALYTICAL CALCULATION OF QUALITY INDICATORS ЖС3ДК-ВІ FOUNDRY HEAT-RESISTANT NICKEL ALLOY

Purpose. Carrying out analytical calculations of the most important parameters that determine the structural and phase stability and workability of the cast heat-resistant nickel alloy ЖС3ДК-ВІ, using known calculation and analytical methods, to assess its general suitability for wide application of modification with various complexes.Research methods. According to the PHACOMP and New PHACOMP calculation methods, the parameters of structural stability were calculated based on the chemical composition of γ-solid solutions: the total number of elec-tron vacancies in the γ-solid solution and the total number of valence electrons in the γ-solid solution dγ, tak-ing into account the values of the parameter of the tendency of the alloy to form topologically densely packed (TDP) phases. The balance of the chemical composition of the alloy was assessed by the ΔE method based on the value of the imbalance parameter of its alloying system, using computer modeling of thermodynamic processes by the CALPHAD method in the program (JMatPro). In accordance with the complex calculation and analytical methodology (ССAM) developed at NU “Zaporizhzhia Polytechnic”, temperature parameters, short-term strength limit values and long-term strength values at different temperatures for the ЖС3ДК-ВІ alloy at different levels of alloying were determined using regression mathematical models obtained on the basis of mathematical processing of known experimental data.Scientific novelty. A complex of computational and analytical studies was carried out and the most important parameters characterizing the structural and phase stability and workability of the cast heat-resistant nickel alloy ZhS3DK-VI were determined.According to the parameters of the imbalance of the alloying system ΔE and the total number of valence elec-trons in the dС, alloy, the ЖС3ДК-ВІ alloy is enought balanced near the average level of element content.It was established that in the entire range of Cr, W, and Mo alloying, the values of the parameters of the PTDP, and dγ decrease slightly monotonically, which indicates a high level of structural stability of the ЖС3ДК-ВІ alloy.The obtained calculation data indicate that the ЖС3ДК-ВІ alloy is clearly not designed for operation at tem-peratures approaching 1000 ºС for 1000 hours.Practical value. The obtained results indicate the sufficient stability of the ЖС3ДК-ВІ alloy and its general suitability for wide application of modification with various complexes to improve the level of physical-mechanical and operational properties.

Effect of long-term exposures at elevated temperatures on evolution of 08Kh18N10Т steel structure

The effect of exposures in the range of 500...10 000 hours at heating temperatures of 450...750 °C on the change in the structure and properties of 08Kh18N10Т steel is studied. It is found that in the early stages of thermal ageing at 450...550 °C, secretions of finely dispersed coherent carbides with an austenitic matrix are formed. With an increase in the duration of exposure and ageing temperature to 650 °C, the size of the carbide particles Me23C6 increase sharply, which, with a certain combination of temperature-time parameters, evolve into a σ-phase with low coherence with a γ-solid solution. However, this phenomenon has little effect on mechanical properties at room temperature.

Studying the effect of heat treatment modes on corrosion resistance of welded joints

Studying the effect of heat treatment modes on corrosion resistance of welded joints

Вплив технології виготовлення випаровуємих катодів на якість іонно-плазмових покриттів лопаток турбін

The article considers coatings deposited on turbine blades via plasma vapor deposition (PVD) method with Ni-Cr-Al-Y cathodes obtained using powder metallurgy (PM) and electron beam remelting process (EBMR). The study analyzes the effect of cathodes manufacturing techniques on surface roughness of rotor turbine blades. Task: to examine a microstructure and chemical composition of the considered cathodes; to quantify a droplet phase of a heat-resistant coating of turbine blades subdivided into size-fractions. Methods used optical microscopy, SEM-analysis. Next results were obtained. In the microstructure of two cathodes under study, it is revealed γ-solid solution with intermetallic Ni-Cr-Al and yttrium-based phases. Simultaneously, distribution of the yttrium phase in the PM-cathode more uniform in compare with EBMR-cathode. Metallographic studies showed that yttrium phase in the structure of the PM-cathode is highly-dispersed, with sizes up to 5 microns, and due to structural and dimensional heredity received during cathode hot isostatic pressing compaction. The structure of the cathode obtained using EBMR-process is a series of the conglomerates of intermetallic phases, with more than 50 microns long, which are branched out on volume. The compliance of the chemical composition of the cathodes under study to requirements of the specifications is established. After the coating deposition on turbine blades by a PVD-method with cathodes under study, were not observed any coating delamination, and their thickness corresponded to the specifications. With a distribution analysis of droplet phase on the turbine blade surface were established that coatings with PM-cathode have been characterized by complete absence of a 65 microns droplet phase, and has half less 25…45 microns droplet phase compared with the EBMR-cathode. Conclusions. The coating with PM-cathode has smaller droplet phase on the turbine blade surface and as a result improved their roughness and gas path surface state. The use of PM in the production of the cathodes for protective coatings provides stable performance of installation and provides long-term operation time of cathodes, compared with the EBMR-cathodes.

Phase Formation during Heating of Amorphous Nickel-Based BNi-3 for Joining of Dissimilar Cobalt-Based Superalloys.

Phase transformations and the melting range of the interlayer BNi-3 were investigated by differential scanning calorimetry, which showed three stages of crystallization during heating. There were three exothermic peaks that indicated crystallization in the solid state. The cobalt-based X-45 and FSX-414 superalloys were bonded with interlayer BNi-3 at a constant holding time of 10 min with bonding temperatures of 1010, 1050, 1100, and 1150 °C using a vacuum diffusion brazing process. Examination of microstructural changes in the base metals with light microscopy and scanning electron microscopy coupled with X-ray spectroscopy based on the energy distribution showed that increasing temperature caused a solidification mode, such that the bonding centerline at 1010 °C/10 min included a γ-solid solution, Ni3B, Ni6Si2B, and Ni3Si. The athermally solidified zone of the transient liquid phase (TLP)-bonded sample at 1050 °C/10 min involved a γ-solid solution, Ni3B, CrB, Ni6Si2B, and Ni3Si. Finally, isothermal solidification was completed within 10 min at 1150 °C. The diffusion-affected zones on both sides had three distinct zones: a coarse block precipitation zone, a fine and needle-like mixed-precipitation zone, and a needle-like precipitation zone. By increasing the bonding temperature, the diffusion-affected zone became wider and led to dissolution.

Creep of single-crystals of nickel-base γ-alloy at temperatures between 1150 °C and 1288 °C

A γ-analogue of the superalloy CMSX-4 that does not contain the strengthening γ′-phase and only consists of the γ-solid solution of nickel has been designed, solidified as single-crystals of different orientations, and tested under creep conditions in the temperature range between 1150 and 1288 °C. The tests have revealed a very high creep anisotropy of this alloy, as was previously found for CMSX-4 at supersolvus temperature of 1288 °C. This creep anisotropy could be explained by the dominance of 011111 octahedral slip. Furthermore, the analysis of the creep data has yielded a high value of the creep activation energy, Qc≈442 kJ/mol, which correlates with the high activation energy of Re diffusion in Ni. This supports the hypothesis that dislocation motion in the γ-matrix of Re-containing superalloys is controlled by the diffusion of the Re atoms segregating at the dislocation core. The Norton stress exponent n is close to 5, which is a typical value for pure metals and their alloys. The absence of γ′-reprecipitation after high-temperature creep tests facilitates microstructural investigations. It has been shown by EBSD that creep deformation results in an increasing misorientation of the existing low angle boundaries. In addition, according to TEM, new low angle boundaries appear due to reactions of the a/2011 mobile dislocations and knitting of new networks.

Some aspects for increasing of heat-temperature strength of casting complex alloyed nickel-based alloys due to effect of redistribution of alloying elements between γ-solid solution and hardening γ′-phase

The positive effect of alloying elements on the thermal stability of the γ-matrix and the strengthening γ'-phase of casting nickel alloys, and consequently, on the increase in their heat-temperature strength is established. The alloying elements inhibit diffusion processes, thereby increasing the creep resistance of alloys at high temperatures and loads. It is found that the most indicative parameters of the phase composition of the test alloys are the alloying elements distribution coefficients between the γ- and γ'-phases. The basic principles of balanced alloying are formulated, on which the choice of the optimal chemical composition of heat-temperature nickel alloys is carried out.

Increasing the heat resistance of cast nickel-based complex alloyed alloys due to the influence of the redistribution of alloying elements between the γ-solid solution and the strengthening intermetallic γ'-phase

The analysis of alloying of the chemical and phase composition of domestic and foreign cast heat-resistant alloys with a nickel matrix is carried out; the tendency to increase the level of heat-resistant properties of cast nickel alloys due to more complex alloying is traced. Recently, expensive rhenium, ruthenium, hafnium, and dysprosium have increasingly been used as alloying elements. The positive effect of these elements on the thermal stability of the γ-matrix and the strengthening γ'-phase is established. The above elements inhibit diffusion processes, thereby increasing the creep resistance of alloys at high temperatures and loads. The evaluation of heatresistant nickel alloys obtained by directional crystallization is given. It is established that the most significant parameters of the phase composition of the studied alloys are the distribution coefficients of alloying elements between the γ' and γ-phases (Ki). The basic principles of balanced alloying, which are used to select the optimal chemical composition of heat-resistant nickel alloys, are formulated. To achieve the maximum heat resistance parameters in the selected heat-resistant nickel alloys alloying system, the calculated value γ/γ' defined by “misfit” was used, which is calculated by the formula: Δа = (аγ-аγ')/ аγ, where аγ and аγ' are the lattice periods of γ and γʹ-phases. Thus, the calculated Δа should be positive for аγ> аγ' and at least two to three times more than for single-crystal heat-resistant nickel alloys with a traditional alloying system, for which Δа = (0.1-0.2) or more. It is shown that misfit (γ/γ') is mainly determined by those alloying elements that increase the аγ most significantly. These elements are Re, Pu, Mo, W, Nb, and Ta in ascending order of influence on the lattice period (аγ) of the phase.

The effect of heat treatment temperature on the resistance to intergranular corrosion of welded joints of heat-resistant nickel alloys inconel 718 and steel 316l

The effect of heat treatment temperature on the resistance to intergranular corrosion of welded joints of heat-resistant nickel alloys inconel 718 and steel 316l

PHASE EQUILIBRIUMIN THE Cu2S – In2S3 – CuI QUASI-TERNARY SYSTEM

The interaction between the components in the Cu 2 S – In 2 S 3 – CuI system has been inverstigated by methods of X-ray analysis and differential-thermal analysis. An isothermal section of the quasi-ternary system at 770 K, two phase diagrams, three polythermal sections and the liquidus surface projection of the system were constructed. The isothermal section of the Cu 2 S – In 2 S 3 – CuI quasi-ternary system at 770 K has been built based on the results of the X-ray analysis. The large regions of the solid solutions based on binary, ternary and quaternary compounds do not form at 770 К. The following one-phase regions were fixedat the temperature: κ-solid solutions based on Cu 2 S with cubic structure (S.G. Fm -3 m ), η-solid solutions based on CuI (S. G. F -43 m ), e-solid solutions based on CuIn 2 S 3 I with a cubic structure (S. G. F -43 m ), δ′-solid solutions based on LTM-In2S3 (S.G. I -4/ amd ), μ-solid solutions based on CuIn 5 S 8 (S.G. Fd 3 m ), γ-solid solutions based on LTM-CuInS 2 (S.G. I -42 d ). These single-phase regions are separated by nine two-phase equilibria. The liquidus surface projection was built based on the two phase diagrams of In 2 S 3 –CuI and CuInS 2 – CuI systems and three polythermal sections CuIn 5 S 8 –CuIn 2 S 3 I, CuInS 2 –CuIn 2 S 3 I, CuInS 2 – “Cu 3 SI”, which have been constracted in this work. In addition, literature data about the interaction in In 2 S 3 – Cu 2 S and Cu 2 S – CuI systems have been used. The liquidus surface projection consists from the areas of primary crystallization of κ-solid solutions based on Cu 2 S, α-solid solutions based on HTM-CuInS 2 , β-solid solutions based on 2-HTM-CuInS 2 , γ-solid solutions based on LTM-CuInS 2 , μ-solid solutions based on CuIn 5 S 8 , δ-solid solutions based on HTM-In 2 S 3 , e-solid solutions based on CuIn 2 S 3 I, η-solid solutions based on CuI. These areas are separated by 18 mono-variant curves and 17 non-variant points.

Phase Transformations in a Precision 40KhNYu-VI Nickel Alloy during Heat Treatment and Nitriding

Abstract—The effect of heat and thermochemical treatment (nitriding) on the structure of the surface regions and the core of 40KhNYu-VI alloy samples have been studied by X-ray diffraction, optical microscopy, and microhardness measurements. The data on the phase transformations have been obtained as follows: the alloy quenched from 1150°C consists of two supersaturated solid solutions based on fcc nickel (γ-solid solution) and bcc chromium (α-solid solution) and a small amount of the Ni3Al phase; subsequent aging at 560°C leads to a decrease in the supersaturation of the γ solid solution and the formation of a higher content of bcc chromium and Ni3Al phases. Nitriding at 540°C leads to the formation of a continuous 3–4-μm-thick layer of the CrN phase, the decomposition of the Ni3Al phase, and the formation of phase AlN in a lower layer 100–140 μm in thickness. The content of the bcc chromium phase in the surface layer decreases. The microhardness measurements after nitriding show that the microhardness is high (up to 1060 HV0.1) for the CrN phase and insignificantly decreases from 740 to 650 HV0.1 in the subsurface layers due to the transformation of Ni3Al into AlN.

A Study of Sulfur and Phosphorus Distribution in a Single Crystal of Refractory Alloy by Transmission Electron Microscopy and MXRSA

The distribution of phosphorus and sulfur impurities in the γ- and γ1-phases of single crystals of alloy ZhS36-VI is studied by high-resolution methods of transmission electron microscopy and microscopic x-ray spectrum analysis. It is shown that these impurities are mostly concentrated in the γ-solid solution, which contains local regions of their high content. The kind of the distribution of the impurities is preserved after testing for long-term strength; the nonuniformity of the distribution of sulfur between the γ- and γ1-phases becomes more manifested, especially for the composition with a high sulfur content.

Substituting Mo for Re in equal weight for Ni based single crystal superalloy

The effect of substituting Mo for Re in the equal weight on high temperature stress rupture properties of Ni based single crystal superalloys has been investigated. The 980 °C/ 250 MPa rupture life decreases with the substitution while the 1100 °C/ 137 MPa life keeps almost unchanged. Both the interface-strengthening effect, i.e. the γ-γ' lattice misfit, and the γ-solid solution hardening effect are nearly fixed with the substitution, which contributes to the success of the substitution. Dislocations are found to shear into γ'-precipitates and climb/glide via the interfaces. The 3D dislocation reconfiguration reveals the complex interaction between the γ'-shearing dislocations, including pair-coupling structure, dislocation reaction and drag effect, which indicates that the plastic deformation of γ'-precipitates is limited. Based on a constitutive model, the stresses rupture life is proportional to the reciprocal of effective diffusivity (1/Deff), meaning that such dislocation's climb via the interfaces is the rate-determining step of creep. The substitution-induced reduction of 1/Deff significantly diminishes with the temperature increasing, due to the Arrhenius equation where the effective diffusivity is strongly affected by temperature. According to this model, the substitution proves useful and the temperature dependence of its strengthening effect is rationalized.

PHASE EQUILIBRIUM IN THE Cu2S – Ga2S3 – In2S3 QUASI-TERNARY SYSTEM AND LOW-TEMPERATURE PHOTOLUMINESCENCE IN THE SINGLE CRYSTALS (Ga55In45)2S300 та (Ga54,59In44,66Er0,75)2S300

The interaction between the components in the Cu2S - Ga2S3 - In2S3 system has been investigated by methods of direct synthesis, X-ray analysis and differential-thermal analysis. 5 polythermal sections, the isothermal section at 820 K and the liquidus surface projection of the Cu2S – Ga2S3 – In2S3 system have been constructed. The presence of solid solutions based on binary and ternary compounds has been found. The existence of the quaternary phase CuGaxIn5-xS8 has been confirmed, where 1.4 ≤ x ≤ 2.05 at 820 K. The two single crystals (Ga55In45)2S300 and (Ga54,59In44,66Er0,75)2S300 have been grown by solution-melt method. In the (Ga55In45)2S300 single crystal at T = 80 K and the excitation at 488 nm a low PL intensity has been observed, which is associated with defects of the single crystal. The PL band with the maximum at 1540 nm in the (Ga54,59In44,66Er0,75)2S300 single crystal is associated with intracenter transitions in the Er3+ ions.The isothermal section of the Cu2S – Ga2S3 – In2S3 quasi-ternary system at 820 K has been built based on the results of the X-ray analysis. Ternary compounds CuInS2 and CuGaS2 form solid solutions with the structure of chalcopyrite with formula CuGa1-xInxS2, 0 ≤ x ≤ 1, sp. gr. I-42d. There are also γ-solid solutions based on CuGa5S8, sp. gr. I-42m; λ-solid solutions based on GaInS3, sp. gr. P61; μ-solid solutions based on Ga0.7In1.3S3, sp. gr. Cmc21, ι-solid solutions based on CuIn5S8, sp. gr. F-43m in the investigated system. The φ-quaternary phase stretched out along 16.7 mol. % Cu2S. It crystallizes in the hexagonal system and forms equilibrium with β-, λ-, ι-solid solutions.The liquidus surface projection of the system has been built based on the literature and our own research results. On the liquidus surface projection of the system, the areas of primary crystallization of α-solid solutions based on 2-HTM-Cu2S, ε-solid solutions based on 2-HTM-Ga2S3, δ-solid solutions based on 1-HTM-Ga2S3, λ-solid solutions on the basis of GaInS3, ψ-solid solutions based on 2-HTM-In2S3, the φ-quaternary phase and the largest region of the primary crystallization of the β-solid solution based on CuGaS2 exist. Small regions of the primary crystallization of the θ-solid solutions based on 2-HTM-CuInS2 and η-solid solutions based on 1-HTM-CuInS2 also exist. All regions are separated by monovariant curves and non-variant points. μ-Solid solutions based on Ga0,7In1,3S3 and γ-solid solutions based on CuGa5S8 do not have the areas of the primary crystallization on the liquidus surface projection of the system due to the nature of their formation.

The effect of heat treatment sequence on microstructure and mechanical properties of diffusion brazed IN-939 superalloy

Conducting the diffusion brazing cycle at 1120 °C for 45 min led to the completion of isothermal solidification and formation of a single-phase Ni-rich γ-solid solution at the joint centerline. Chromium-rich boride precipitates with blocky and acicular morphologies were detected in the diffusion affected zone (DAZ) of all the bonds. The post bond heat treatment of the brazed joint (HT-3 sample) resulted in complete elimination of DAZ boride precipitates and obtaining high levels of homogeneity across the joint region. Performing the brazing cycle between the solution treatment and the double aging cycle (HT-1 sample), as well as after the full heat treatment of the base metal (HT-2 sample), had a minor effect on the morphology of the joint region. While all the heat treatment sequences raised the microhardness values across the bonding regions, the HT-2 sequence reduced the microhardness levels in the isothermally solidified zone (ISZ). The HT-3 sequence improved the joint efficiency up to the remarkable value of 91%. In the as-brazed sample, the fracture path was observed in the ISZ and a dimple-like morphology was detected in the fracture surface. In HT-1 sample, the fracture occurred within the hard DAZ precipitates and a semi-cleavage morphology was detected in the fracture surface.

Rheological Properties of the EP742-ID Alloy in the Context of Integrated Computational Materials Science and Engineering: Part I. Results of Experimental Investigations

Rheological properties of the EP742-ID alloy are investigated during high-temperature compression tests of cylindrical samples with various ratios of homological initial sizes of diameter and height (d0/h0). It is shown by the results of tests in ranges of temperature t = 1000–1150°C and initial deformation rates e0= 3 × 10–2–3 × 10–4 s–1 that an increase in the compression flow tension manifests itself at all temperatures and deformation rates with an increase in ratio d0/h0 with the linear dependence on the magnitude of e0 and ratio d0/h0. The procedure of recalculating characteristics of the deformation resistance for the specified ratio of homological parameters is proposed. An increase in the compression flow tension is associated with an increase in the rigidity coefficient of the samples and their specific contact surfaces. The temperature dependence of the apparent activation energy of the plastic deformation (Qdef) of the alloy and its relation with the phase composition and running conditions of the dynamic recrystallization of the γ-solid solution are established. The magnitude of Qdef in temperature conditions of the development onset of the dynamic recrystallization of the γ-solid solution (1000–1050°C) is 959 kJ/mol for samples with d0/h0 = 0.75. The largest values of Qdef for the samples with d0/h0 = 0.75 equal to 1248 and 1790 kJ/mol are observed in a temperature region of the intense dissolution and coagulation of the grain-boundary γ′-phase (1050–1100°C). The value of Qdef for the samples with d0/h0 = 3.0 increases to 2277 kJ/mol in this temperature range. The apparent activation energy of the plastic deformation lowers to 869 kJ/mol in the temperature region of the γ-solid solution with grain-boundary primary and secondary carbides (1100–1150°C). The results of compression of alloy samples during single and repeated sequential loading with various durations of pauses between deformation actions are presented. It is shown that no metadynamic recrystallization occurs in the experimental conditions in the γ + γ′-region, while it runs slowly in the γ-region.

NiCrBSi coating obtained by laser cladding and subsequent deformation processing

NiCrBSi coating (Ni: base; Cr: 18.2 wt%; B: 3.3 wt%; Si: 4.2 wt%; C: 0.92 wt%; Fe: 2.6 wt%) formed by gas powder laser cladding is subjected to subsequent deformation processing, namely, frictional treatment with a sliding indenter made of dense cubic boron nitride in air under loads of 300 to 700 N, with 2 to 5 scans of the surface. This treatment strengthens the surface and forms favorable residual compressive stress, whose level increases with the load on the indenter. Frictional treatment under loads of 500 N and higher causes intensive strain-induced dissolution of Ni3B borides and Cr7C3 carbides in a Ni-based γ-solid solution.

Use of coatings for protection of welded joints of steels, their structure and properties

The paper studies the structure and demonstrates the efficiency of application of eutectic nickel coatings for protection of welded joints of the 10G2S-type steels from corrosive action. It increases simultaneously with the increase of eutectic content and chemical compounds along the grain boundaries of the γ-solid solution based on nickel. The refinement of the coatings’ structure and the reduction of their heterogeneity allow enhancing the protective properties and resistance of welded joints to corrosion.