High-temperature Nickel Alloys Research Articles

Development of the technology of reconditioning the sealing element of nozzle blade sector from difficult-to-weld high-temperature nickel alloy of ZhS6 type by microplasma powder surfacing

Development of the technology of reconditioning the sealing element of nozzle blade sector from difficult-to-weld high-temperature nickel alloy of ZhS6 type by microplasma powder surfacing

The Impact of Surface Treatment on the Structure and Chemistry of Protective Oxide-Scale in High-Temperature Oxidation-Resistant Nickel Alloys

The Impact of Surface Treatment on the Structure and Chemistry of Protective Oxide-Scale in High-Temperature Oxidation-Resistant Nickel Alloys

Performance of Public Film Cooling Geometries Produced Through Additive Manufacturing

Abstract Film cooling is an essential cooling technology to allow modern gas turbines to operate at high temperatures. For years, researchers in this community have worked to improve the effectiveness of film cooling configurations by maximizing the coolant coverage and minimizing the heat flux from the hot gas into the part. Working toward this goal has generated many promising film cooling concepts with unique shapes and configurations. However, until recently, many of these designs were challenging to manufacture in actual turbine hardware due to limitations with legacy manufacturing methods. Now, with the advances in additive manufacturing, it is possible to create turbine parts using high-temperature nickel alloys that feature detailed and unique geometry features. Armed with this new manufacturing power, this study aims to build and test the promising designs from the public literature that were previously difficult or impossible to implement. In this study, different cooling hole designs were manufactured in test coupons using a laser powder bed fusion process. Each nickel alloy coupon featured a single row of engine scale cooling holes, fed by a microchannel. To evaluate performance, the overall cooling effectiveness of each coupon was measured using a matched Biot test at engine relevant conditions. The results showed that certain hole shapes are better suited for additive manufacturing than others and that the manufacturing process can cause significant deviations from the performance reported in the literature.

Selection of technological variants of argon-arc and electron-beam welding of a high-temperature nickel alloy in a thermally strengthened state

ABSTRACT The paper clarifies the influence of TIG and EB welding variants and highly temperature-resistant nickel superalloy VG159 being in a heat-hardenable condition without post-heat treatment on mechanical properties and structure of welded joints. The research trackles the problem of short- and long-term durability at a temperature of 850 and 870°С and covers the issue of resilience. The filler materials for argon-arc welding and relevant modes for electron-beam welding are selected. They provide a high complex of mechanical properties and an appropriate structure of welded joints

Повышение окислительной стойкости жаропрочного никелевого сплава ЭП-718 ИД с помощью комбинированной технологии инженерии поверхности

Повышение окислительной стойкости жаропрочного никелевого сплава ЭП-718 ИД с помощью комбинированной технологии инженерии поверхности

Effect of High-Temperature Coatings on the Reliability Characteristics of GTE Blade Elements

The paper presents the results of experimental studies of the effect of high-temperature coatings on turbine and compressor blades made of high-temperature nickel and titanium alloys on the service life characteristics during gas corrosion, thermal loading, and thermomechanical loading: quantitative cracking resistance characteristics, fracture toughness K1C, and fatigue life.

Vacuum diffusion welding of γ-TiAl intermetallic with high-temperature nickel alloy with application of intermediate Al/Ni nanolayers

Vacuum diffusion welding of γ-TiAl intermetallic with high-temperature nickel alloy with application of intermediate Al/Ni nanolayers

Диффузионная сварка в вакууме интерметаллида γ-TiAl с жаропрочным никелевым сплавом с применением нанопрослоек Al/Ni

Диффузионная сварка в вакууме интерметаллида γ-TiAl с жаропрочным никелевым сплавом с применением нанопрослоек Al/Ni

Damage analysis of 601 nickel superalloy in eutectic Na2CO3/NaCl molten salt under isothermal and thermal cycling conditions

Establishing compatibility of high-temperature nickel alloys with molten salt phase-change materials is critical for the development of thermal energy storage for future concentrating solar power systems. This paper investigates the behaviour of alloy 601 in a 59.5 %wt Na2CO3/40.5 %wt NaCl eutectic salt mixture under thermal cycling and isothermal conditions. Under both conditions it was found that chromium was depleted from the alloy at a linear rate, inducing porosity in the metal. The corrosion scale consisted primarily of iron oxide, although chromium and aluminium are present in the inner layers. The scale was found not to be protective and does not form a barrier to salt ingress into the alloy’s porous region, enabling depletion to continue unimpeded. Thermal cycling tests show scale depletion and thickness reduction compared to isothermal tests, implying that depletion and scale growth is related to the time which the salt is molten in the system. Given solar thermal energy using phase-change salt storage is cyclic, this work provides significant insight into corrosion under in-service conditions, which is critical for successful plant design.

A NEW WELDING MATERIAL FOR REGENERATION IN THE WELDING TECHNOLOGY BASED ON NICKEL. ANALYSIS OF THE PROCESSABILITY OF APPLICATION OF THE EXPERIMENTAL FILLER IN THE REGENERATION OF SUPERALLOY CASTINGS VIA TIG WELDING AND OTHER TECHNOLOGIES

This work involves an analysis of high-chromium high-temperature deformable wieldable nickel alloys for use in GTE repair assemblies. It is shown that the alloys EP868 (VZh98) and Haynes 230 can be used in welded assemblies with an operating temperature of 800-1100 °C. The alloys Nimonic 81, Nimonic 91, IN 935, IN 939, and Nicrotan 2100 GT also have a high potential for use in welded assemblies. They are characterized by a combination of good weldability, high-temperature strength, and resistance to scaling. There have been conducted studies on high-temperature salt corrosion of model nickel alloys. They allowed establishing the patterns of the impact of base metal alloying with chromium, aluminum, titanium, cobalt, tungsten, molybdenum, niobium, tantalum and rare earth metals on the critical temperature of the start of salt corrosion Tcor and the alloy mass loss. It has been established that alloys with a moderate concentration (13-16%) of chromium can possess satisfactory hightemperature corrosion resistance (HTC resistance) under the operating conditions of ship GTE. The HTC resistance of CrAl-Ti alloys improves upon reaching the ratio Ti/Al ˃ 1. Meanwhile, the ratio Ti/Al ˂ 1 promotes the formation of corrosion products with low protective properties. The positive effect of tantalum on the HTC resistance of alloys is manifested at higher test temperatures than that of titanium, and the total content of molybdenum and tungsten in alloys is limited by the condition 8Mo2 – 2W2 = 89. The presence of refractory elements stabilizes the strengthening phase and prevents formation of the ɳ-phase. However, their excess promotes formation of the embrittling topologically close packed (TCP) phases and boundary carbides of an unfavorable morphology. Based on the studies of the HTC resistance, there has been identified a class of model high-temperature corrosionresistant nickel alloys with a moderate or high chromium content (30%), Ti/Al ˃ 1, and a balanced content of refractory and rare-earth elements.

A NEW WELDING MATERIAL FOR REGENERATION IN THE WELDING TECHNOLOGY BASED ON NICKEL. DEVELOPMENT OF A NEW HIGH-TEMPERATURE AND CORROSION-RESISTANT WELDING MATERIAL FOR THE REGENERATION OF DEFECTS IN HNA CASTINGS. ANALYSIS OF EXISTING FUELLING STATIONS TYPES AND VEHICLES USING HYDROGEN, HYDROGEN PRODUCTION AND STORING METHODS

This work involves an analysis of high-chromium high-temperature deformable wieldable nickel alloys for use in GTE repair assemblies. It is shown that the alloys EP868 (VZh98) and Haynes 230 can be used in welded assemblies with an operating temperature of 800-1100 °C. The alloys Nimonic 81, Nimonic 91, IN 935, IN 939, and Nicrotan 2100 GT also have a high potential for use in welded assemblies. They are characterized by a combination of good weldability, high-temperature strength, and resistance to scaling. There have been conducted studies on high-temperature salt corrosion of model nickel alloys. They allowed establishing the patterns of the impact of base metal alloying with chromium, aluminum, titanium, cobalt, tungsten, molybdenum, niobium, tantalum and rare earth metals on the critical temperature of the start of salt corrosion Tcor and the alloy mass loss. It has been established that alloys with a moderate concentration (13-16%) of chromium can possess satisfactory hightemperature corrosion resistance (HTC resistance) under the operating conditions of ship GTE. The HTC resistance of CrAl-Ti alloys improves upon reaching the ratio Ti/Al ˃ 1. Meanwhile, the ratio Ti/Al ˂ 1 promotes the formation of corrosion products with low protective properties. The positive effect of tantalum on the HTC resistance of alloys is manifested at higher test temperatures than that of titanium, and the total content of molybdenum and tungsten in alloys is limited by the condition 8Mo2 – 2W2 = 89. The presence of refractory elements stabilizes the strengthening phase and prevents formation of the ɳ-phase. However, their excess promotes formation of the embrittling topologically close packed (TCP) phases and boundary carbides of an unfavorable morphology. Based on the studies of the HTC resistance, there has been identified a class of model high-temperature corrosionresistant nickel alloys with a moderate or high chromium content (30%), Ti/Al ˃ 1, and a balanced content of refractory and rare-earth elements.

Repair surfacing of gas turbine engine blades from high-temperature nickel alloys with surface defects and damage

Repair surfacing of gas turbine engine blades from high-temperature nickel alloys with surface defects and damage

Ремонтная наплавка лопаток газовых турбин из жаропрочных никелевых сплавов с поверхностными дефектами и повреждениями

Ремонтная наплавка лопаток газовых турбин из жаропрочных никелевых сплавов с поверхностными дефектами и повреждениями

Optimization of the composition of the foundry heat-resistant nickel alloy for the manufacture of cast working blades using the method of (mono) crystallization for promising gas turbines

Purpose. Development of the composition of a heat-resistant nickel alloy not containing rhenium for the manufacture of cast working blades by the method of directional (mono) crystallization. The alloy should have increased structural stability, while maintaining the level of mechanical, anti-corrosion and heat-resistant properties and a significant reduction in cost.Research methods. To estimate the structural and phase stability of high-temperature nickel alloys, various calculation methods were used: « ΔE-method» for assessing the balance of the chemical composition of the alloys by the value of the unbalance parameter of the doping system; PHACOMP and New PHACOMP – on the chemical composition of γ- solid solutions; developed in ZNTU complex methodology that establishes the relationship between the various parameters of structural stability.Results. Computing-analytical methods have been used to develop the composition of an economically-alloyed heat-resistant nickel alloy for the manufacture of cast blades by the method of directional (mono) crystallization, which does not contain expensive imported rhenium.Scientific novelty. Using computational and analytical methods, a composition of a heat-resistant nickel alloy with increased structural stability, resistance to high-temperature corrosion, and heat-resistant properties necessary for cast single-crystal products has been developed.Improvement of structural stability and improvement of the complex of properties of the developed alloy is provided by balanced doping with tantalum and tungsten (8.5 % at an average level), at reducing the content of carbon, molybdenum and cobalt by almost 2 times, and absence of the most expensive component in the composition – rhenium.Practical value. The developed economically-alloyed heat-resistant nickel alloy, which does not contain expensive rhenium, provides all the necessary operational properties, with a significant reduction in cost, and can be recommended for use in the manufacture of single-crystal cast blades of land-based gas turbine units.

A NEW WELDING MATERIAL FOR REGENERATION IN THE WELDING TECHNOLOGY BASED ON NICKEL. PRINCIPLES OF DOPING OF HIGH-TEMPERATURE NICKEL ALLOYS RESISTANT TO HIGH-TEMPERATURE CORROSION

This work involves an analysis of high-chromium high-temperature deformable wieldable nickel alloys for use in GTE repair assemblies. It is shown that the alloys EP868 (VZh98) and Haynes 230 can be used in welded assemblies with an operating temperature of 800-1100 °C. The alloys Nimonic 81, Nimonic 91, IN 935, IN 939, and Nicrotan 2100 GT also have a high potential for use in welded assemblies. They are characterized by a combination of good weldability, high-temperature strength, and resistance to scaling. There have been conducted studies on high-temperature salt corrosion of model nickel alloys. They allowed establishing the patterns of the impact of base metal alloying with chromium, aluminum, titanium, cobalt, tungsten, molybdenum, niobium, tantalum and rare earth metals on the critical temperature of the start of salt corrosion Tcor and the alloy mass loss. It has been established that alloys with a moderate concentration (13-16%) of chromium can possess satisfactory hightemperature corrosion resistance (HTC resistance) under the operating conditions of ship GTE. The HTC resistance of CrAl-Ti alloys improves upon reaching the ratio Ti/Al ˃ 1. Meanwhile, the ratio Ti/Al ˂ 1 promotes the formation of corrosion products with low protective properties. The positive effect of tantalum on the HTC resistance of alloys is manifested at higher test temperatures than that of titanium, and the total content of molybdenum and tungsten in alloys is limited by the condition 8Mo2 – 2W2 = 89. The presence of refractory elements stabilizes the strengthening phase and prevents formation of the ɳ-phase. However, their excess promotes formation of the embrittling topologically close packed (TCP) phases and boundary carbides of an unfavorable morphology. Based on the studies of the HTC resistance, there has been identified a class of model high-temperature corrosionresistant nickel alloys with a moderate or high chromium content (30%), Ti/Al ˃ 1, and a balanced content of refractory and rare-earth elements.

Influence of Surfacing Technologies on Structure Formation of High-Temperature Nickel Alloys

The paper presents the results of studying the formation of structure and properties of metals when using additive technologies, such as arc and laser surfacing of highly alloyed nickel alloys. The main problem of nickel-chromium alloys during treatment with highly concentrated energy sources (welding, surfacing, soldering, plasma and laser treatment) consists in low strength and heat resistance after heating to high temperatures and rapid cooling, which is typical for these methods. The maximum high-temperature strength of such alloys is achieved after quenching and subsequent aging resulting in the formation of finely-dispersed γ′- phase precipitates, which inhibit plastic deformation. However, the achieved level of high-temperature strength of nickel alloys is often reduced significantly as a result of thermal effects and unfavorable structural changes during subsequent treatment (welding, surfacing). The paper presents the results of studying the structure, phase composition and properties of EP648 alloy during argon-arc surfacing. A comparison with the EP648 alloy structures obtained by laser surfacing is provided. It was established that argon-arc welding of EP648 alloy in combination with ultrasonic treatment creates an additional effect of increasing phase dispersion, which leads to an increase in hightemperature strength of the alloy.

A Through-Hole Lead Connection Method for Thin-Film Thermocouples on Turbine Blades.

To solve the current problems with thin-film thermocouple signals on turbine blades in ultra-high temperature environments, this study explores the use of a through-hole lead connection technology for high-temperature resistant nickel alloys. The technique includes through-hole processing, insulation layer preparation, and filling and fixing of a high-temperature resistant conductive paste. The through-hole lead connection preparation process was optimized by investigating the influence of the inner diameter of the through-hole, solder volume, and temperature treatment on the contact strength and surface roughness of the thin-film for contact resistance. Finally, the technology was combined with a thin-film thermocouple to perform multiple thermal cycling experiments on the surface of the turbine blade at a temperature of 1000 °C. The results show that the through-hole lead connection technology can achieve a stable output of the thin-film thermocouple signal on the turbine blade.

Tailoring the Properties in Functionally Graded Alloy Inconel 718 Using Additive Technologies

A novel method for forming “programmed” mechanical properties in local components of a part by controlling the microstructure of the alloy under additive production is suggested. It is shown that the thermal fields acting during the additive production may be used for manipulating the preferred orientation of the growing crystals and forming different-size grains, which affects the mechanical characteristics. A gradient material from a high-temperature nickel alloy Inconel 718 with coarse elongated grains in the core and fine-grained microstructure in the external shell is produced and shown to possess higher operating characteristics than the alloy fabricated by the conventional process.

Effect of Heat Treatment on the Structure and Phase Composition of a High-Temperature Nickel Alloy Obtained by Laser Cladding

Modes of laser cladding of heat-resistant nickel alloy Inconel 625 are considered. The gas-powder flow is studied and optimized as a function of the flow rate of the protective and transporting gas. The effect of the heat treatment modes on the structure and phase composition of the alloy is analyzed. Amode producing compact samples of the alloy is worked out.

A NEW WELDING MATERIAL FOR REGENERATION IN THE WELDING TECHNOLOGY BASED ON NICKEL. ANALYSIS OF THE COMPOSITION AND PROPERTIES OF DEFORMABLE HEAT-RESISTANT HIGH-CHROMIUM NICKEL-BASED ALLOYS FOR WELDED PARTS. ANALYSIS OF EXISTING FUELLING STATIONS TYPES AND VEHICLES USING HYDROGEN, HYDROGEN PRODUCTION AND STORING METHODS

This work involves an analysis of high-chromium high-temperature deformable wieldable nickel alloys for use in GTE repair assemblies. It is shown that the alloys EP868 (VZh98) and Haynes 230 can be used in welded assemblies with an operating temperature of 800-1100 °C. The alloys Nimonic 81, Nimonic 91, IN 935, IN 939, and Nicrotan 2100 GT also have a high potential for use in welded assemblies. They are characterized by a combination of good weldability, high-temperature strength, and resistance to scaling. There have been conducted studies on high-temperature salt corrosion of model nickel alloys. They allowed establishing the patterns of the impact of base metal alloying with chromium, aluminum, titanium, cobalt, tungsten, molybdenum, niobium, tantalum and rare earth metals on the critical temperature of the start of salt corrosion Tcor and the alloy mass loss. It has been established that alloys with a moderate concentration (13-16%) of chromium can possess satisfactory hightemperature corrosion resistance (HTC resistance) under the operating conditions of ship GTE. The HTC resistance of CrAl-Ti alloys improves upon reaching the ratio Ti/Al ˃ 1. Meanwhile, the ratio Ti/Al ˂ 1 promotes the formation of corrosion products with low protective properties. The positive effect of tantalum on the HTC resistance of alloys is manifested at higher test temperatures than that of titanium, and the total content of molybdenum and tungsten in alloys is limited by the condition 8Mo2 – 2W2 = 89. The presence of refractory elements stabilizes the strengthening phase and prevents formation of the ɳ-phase. However, their excess promotes formation of the embrittling topologically close packed (TCP) phases and boundary carbides of an unfavorable morphology. Based on the studies of the HTC resistance, there has been identified a class of model high-temperature corrosionresistant nickel alloys with a moderate or high chromium content (30%), Ti/Al ˃ 1, and a balanced content of refractory and rare-earth elements.