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The results of complex studies on the brazing filler metal of the Cu–Mn–Co system alloyed with iron in the range of 1…5 wt. % are presented. The melting point was determined through calculation, and it was shown that increasing the concentration of iron from 1 to 5 wt. % leads to a slight (from 912 to 923 °C) increase in the temperature of the solidus and a significant increase in the temperature of the liquidus (from 931 to 1027 °C). At the same time, the melting temperature range expands to 104 °C. The results of experimental studies on the spread of brazing filler metal on Kovar and corrosion-resistant steel have established that an increase in the iron concentration up to 5 % contributes not only to an increase in the temperature of the liquidus but also to an increase in the spread area, which is due to the melting temperature of a copper-based solid solution. Local micro-X-ray spectral analysis established a discrete distribution of constituent elements and showed that the brazing filler metal, after spreading, contains two solid solutions: copper-based and manganese-based. The research results on the Kovar-corrosion-resistant steel brazed joints have demonstrated that the addition of iron to the Cu–Mn–Co–Fe alloy leads to an increase in microhardness and shear strength. [ABSTRACT FROM AUTHOR]

When brazing of heat-resistant nickel alloys (HSN) with traditional industrial brazing filler metals of the Ni−Cr−(B, Si) systems, the formation of brittle intermetallic compounds, namely, silicides and borides, occurs in the brazed seams. In order to prevent the formation of such undesirable brittle phases in brazed joints of heat-resistant nickel alloys, investigation is conducted using high-entropy alloys as brazing filler metals. This work shows the possibility of creating multicomponent high-entropy brazing filler metals based on the NiCoCrPdGe system, using calculation methods, binary state diagrams of metal systems and taking into account the classic Hume-Rothery solid-solution formation criteria. A number of thermodynamic parameters (ΔSm, ΔHm, δ, Ωm, VECm) and the liquidus temperature are determined by calculation, and their corresponding dependences on the content of alloying components in the alloys of the NiCoCrPdGe system are constructed. The limiting range of alloying of experimental alloys is established, within which the values of these thermodynamic quantities correspond to the parameters applied to high-entropy alloys and contribute to the formation of a solidsolution structure with an f.c.c. lattice. Based on the obtained data, a section of the liquidus surface for the alloys of the NiCoCrPdGe system is plotted. According to the results of the conducted investigation, the limiting concentration limits of the depressant, namely, germanium, which ensure an acceptable melting temperature of the brazing filler metals when brazing heatresistant nickel alloys, are determined. According to the results of experimental studies, it is established that the alloy of the NiCoCrPdGe5 system is characterized by a two-phase dendritic structure. As determined by means of the calculation method, the volume fraction of the solid solution is of 72.54−75.47%. [ABSTRACT FROM AUTHOR]

The main goal of this work is to determine the melting temperature range and phase composition of multicomponent Ni-based alloys by applying the methods of design of alloys (CALPNAD method) in combination with statistical processing of the results. In particular, the liquidus and solidus temperatures for a number of experimental alloys of the Ni–Cr–Co–Al–(Ме) system are calculated. The degree of influence of adhesive-active elements (Ti, Nb, Zr) on the liquidus temperature and phase composition of alloys of this system is established. The approximate content of alloying elements to ensure the required melting point of experimental filler metals is determined. As shown, alloying zirconium significantly reduces the solidus temperature thus significantly expanding the melting range of experimental alloys. This effect is associated with the formation of low-temperature zirconium eutectic. The influence of titanium and niobium on the amount and thermal stability of the γ′-phase in experimental alloys is studied. The influence of refractory components (Mo, W, Re) on the presence of topologically close-packed (TCP) phases is studied. As noted, partial replacement of tungsten by rhenium in experimental Ni–Cr–Co–Al–(Ме)-based alloys significantly reduces the amount of harmful µ- and p-phases. [ABSTRACT FROM AUTHOR]

The work presents the results of metallographic and X-ray microspectral studies of molybdenum-Kovar overlap joints, which were produced by vacuum brazing with application of brazing filler metal based on Cu-Mn-Co system. The influence of soaking at brazing temperature on brazed seam structure formation was studied. Local X-ray microspectral analysis was used to determine the number of structural components of the brazed seam: copper-based solid solution, individual iron-based grains, reaction layer in the form of a continuous band on molybdenum - brazing filler metal interface. It was found that longer soaking at the brazing temperature promotes an increase of the reaction layer width from 1 to 3 ~m and leads to formation of a faceted morphology from the brazed seam side and to microcracks initiation in it, but it does not affect molybdenum concentration, which at different soaking (1…15 min.) is in the range of 55.81…59.05 wt. %. In the solid solution (matrix) manganese concentration decreases with longer soaking, copper concentration rises, but the quantity of iron practically does not change, and it is in the range of 4.52… 4.95 wt. %. In single grains of the dark phase, observed near the interface with Kovar, longer soaking promotes an increase of iron and nickel concentration and lowering of manganese and copper content. [ABSTRACT FROM AUTHOR]

Modern brazing filler metals for brazing high-temperature nickel alloys are complex alloys, where the components should provide the required level of strength, high-temperature resistance, high-temperature corrosion resistance and other service properties of brazed joints. However, establishing the optimum composition to obtain the desired set of properties is a non-trivial task, requiring considerable investment of time and money. The work is a study of applicability of the method of mathematical modeling of thermodynamic processes (CALPHAD) during development of multicomponent brazing filler metals for brazing high-temperature nickel alloys. During performance of investigations, using CALPHAD computational procedure, melting temperature ranges were determined for a number of alloys of Ni–Cr–Co–Al–(Ме)–Ta system. Calculated data were obtained on the influence of adhesion-active elements of group IV and V of the periodic table on liquidus temperature and phase composition of the basic nickel alloy. In particular, their impact on the quantity and thermal stability of γ'-phase and σ-phase was determined. Thermodynamic calculated data, obtained with application of mathematical modeling method, were used during development and investigation of a number of promising brazing filler metals for brazing high-temperature nickel alloys, including single-crystal high-temperature nickel alloy ZhS-32VI. 21 Ref., 8 Fig. [ABSTRACT FROM AUTHOR]

The paper presents the technological characteristics of multicomponent nickel brazing alloys with a reduced amount of zirconium, which does not exceed 2% wt. Their temperature range of melting and wetting of heat-resistant nickel alloy ZhS6U are investigated. On the basis of the experimental data and using the methods of statistical analysis, a surface described a dependence of the spreading area of the experimental brazing alloys of the Ni-Cr-Co-W-Mo-Al-(Nb, Ti, Zr) system on the content of zirconium, titanium and niobium is constructed. In the process of analyzing the experimental data, the positive influence of niobium and titanium on the spreading of multicomponent brazing filler metal over substrates of the heat-resistant cast nickel alloy ZhS6U is established. As shown, in alloys with an increased amount of titanium the alloying with zirconium up to 1% wt. leads to a decrease in the spreading area by 15%. With a subsequent increase in the content of zirconium to 2%, the spreading area practically does not change. In alloys with a low titanium concentration, but with increased niobium content, alloying with zirconium in an amount of 2% wt. promotes a stable increase in the spreading area (up to 35%) and ensures the formation of a contact wetting angle within 10-11°. This is due to the presence in these brazing filler metal of a low-melting eutectic enriched with zirconium with a solidus temperature at level 1101-1103°C, which is confirmed by the results of hightemperature differential thermal analysis and micro-X-ray spectral studies. [ABSTRACT FROM AUTHOR]

The features of spreading of brazing filler metal of Cu-Mn-Co system over molybdenum and Kovar were established based on the performed studies. Micro X-ray spectral analysis determined that zonal crystallization of a brazing filler metal droplet on the base metal substrate occurs during spreading: pronounced areas of copper-based solid solution (Cu-12.92Mn-4.69Co) form along the outer perimeter of the droplet, and dendrites of manganese-based solid solution, characterized by a higher melting point, are crystallized in the drop central part. It has been experimentally proven that an increase in the heating temperature contributes to an increase in the spreading area of the brazing filler metal by improving the spreading of copper-based solid solution. It was found that a copper-based solid solution forms in the brazed seam of Kovar-molybdenum dissimilar joints, and a molybdenum-based reaction layer (about 1 μm wide), crystallizes at the molybdenum-brazing filler metal interface. This layer is enriched in cobalt (15.80%) and manganese (14.12%) and contains a small amount of copper (1.63%). %). As a result of mechanical tests of Kovar-molybdenum overlap joints under static loads at room temperature, destruction occurs partly along the brazed seam and partly along the base metal - molybdenum. 14 Ref., 2 Tabl., 6 Fig. [ABSTRACT FROM AUTHOR]

The paper presents the results of studies of the influence of cobalt on the structure and mechanical properties of kovar (29НК)-stainless steel (12X18H10) brazed dissimilar joints obtained by vacuum brazing using brazing filler metal of the Cu-Mn-Co system. Micro X-ray spectral studies of brazed dissimilar joints prove that a structure of a solid solution based on copper is formed in brazed joints, which contains a small amount of discrete grains of the γ-phase (solid solution based on Fe-Mn-Co). An increase in the concentration of cobalt in the initial brazing filler metal from 0.5 to 4.5% wt. leads to a slight increase in its concentration in a solid solution based on copper and a significant increase in its concentration in discrete grains of the γ-phase--from 8.44 to 19.7% mass. Such structural features of brazed joints positively affect their mechanical properties and contribute to an increase in the shear strength of kovar-stainless steel brazed overlap dissimilar joints from 374 to 434 MPa. [ABSTRACT FROM AUTHOR]

The results of investigations of pre‑eutectic alloys of the Cu – P – Sb system are presented. The melting temperature interval was determined using high‑temperature differential thermal analysis. It was found that antimony alloying of copper‑phosphorus pre‑eutectic alloy provides a decrease in the temperature of solidus and liquidus. On the basis of experimental and literature data, the surfaces of liquidus and solidus of ternary alloys were constructed. Using micro‑X‑ray spectral analysis, the chemical composition and a number of structural components of the Cu ‑ 6.29P ‑ 1.97Sb alloy were determined. The influence of antimony on technological and mechanical properties, as well as morphology of cast ternary pre‑eutectic copper‑phosphorous alloys is shown. 10 Ref., 2 Tabl., 6 Fig. [ABSTRACT FROM AUTHOR]

Copyright of Metallophysics & Advanced Technologies / Metallofizika i Novejsie Tehnologii is the property of G.V. Kurdyumov Institute for Metal Physics, N.A.S.U and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Metallophysics & Advanced Technologies / Metallofizika i Novejsie Tehnologii is the property of G.V. Kurdyumov Institute for Metal Physics, N.A.S.U and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Metallophysics & Advanced Technologies / Metallofizika i Novejsie Tehnologii is the property of G.V. Kurdyumov Institute for Metal Physics, N.A.S.U and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)