Application of Nanophases Stability Thermodynamics to Advanced Alloys

2012 ◽  
Vol 550-553 ◽  
pp. 2676-2679
Author(s):  
Yury A. Minaev
Keyword(s):  
High Temperature ◽  
Nickel Alloys ◽  
Disjoining Pressure ◽  
High Temperature Strength ◽  
Dispersion Hardening ◽  
Metal Melts ◽  
Thermodynamic Criterion ◽  
Surface Phases ◽  
Specific Variation ◽  
Analysis Of Stability

The thermodynamic analysis of stability conditions was carried out for disperse heterophase systems obtained by a method of NSP put in metal melts for high-temperature strength of the nickel alloys. For a thermodynamic criterion (К) of stability was selected the specific variation of a free energy of the process of a disperse system degradation (referred to unit of a surface phases contact change). The analysis was carried out in view of formation of thick and thin elastic wetting films and takes in account a disjoining pressure. Obtained new thermodynamically rigorous criterions can be used, if the isotherm of a disjoining pressure is measured. The derived criterions are simplified in the Young approximation. In this case the criterion are expressed through measurable interfacial performances - interfacial tension and wetting angles. The application of a stability condition gives a simple outcome: aggregation of NSP does not happen at a wetting angles ≤ 750. On a basis of own experimental data the evaluations are carried out for possibility of using of some compounds as exogenous modifiers of a nickel alloys. The example of dispersion hardening of high-temperature strength nickel alloy is reduced.

Thermodynamics of Advanced Alloys Modification by Exogenous Nanophases

2012 ◽  
Vol 587 ◽  
pp. 1-5
Author(s):  
Y.A. Minaev
Keyword(s):  
Nickel Alloys ◽  
Thermodynamic Description ◽  
Disjoining Pressure ◽  
High Temperature Strength ◽  
Dispersion Hardening ◽  
Thermodynamic Criterion ◽  
Surface Phases ◽  
Specific Variation ◽  
Definition Of ◽  
Ceramic Compounds

The thermodynamic analysis of a ceramic compound solubility was carried out for ceramic compounds which may be used for dispersion hardening of advanced nickel alloys. The thermodynamic description of stability conditions was completed for a disperse heterophase systems consists of metal melt – nanosize phases (NSP). For a thermodynamic criterion (К) of stability was selected the specific variation of a free energy of the process of a disperse system degradation (referred to change of unit of a surface phases contact). The analysis was executed in view of formation of thick and thin elastic wetting films and takes in account a disjoining pressure. The above definition of new thermodynamically rigorous criterions becomes physically real, if the isotherm of a disjoining pressure is measured. The derived criterions are simplified in the Young approximation. In this case the criterion are expressed through measurable interfacial performances - interfacial tension and wetting angles. The application of a stability condition gives a simple outcome: aggregation of NSP does not happen at a wetting angles ≤ 600. On a basis of own experimental data the evaluations are carried out for possibility of using of some compounds as exogenous modifiers of a nickel alloys. The example of dispersion hardening of high-temperature strength nickel alloy and improving its heat resisting properties is reduced.

Influence of Thermo-Mechanical Processing on the Microstructure of Beryllia Dispersed Nickel Alloys

1973 ◽  
Vol 31 ◽  
pp. 184-185
Author(s):  
M.S. Grewal ◽  
S.A. Sastri ◽  
N.J. Grant
Keyword(s):  
High Temperature ◽  
Nickel Alloys ◽  
Thermomechanical Processing ◽  
Cold Work ◽  
High Temperature Strength ◽  
Strengthening Effect ◽  
Mechanical Processing ◽  
Uniform Dispersion ◽  
Oxide Particles ◽  
Nickel Base

Currently there is a great interest in developing nickel base alloys with fine and uniform dispersion of stable oxide particles, for high temperature applications. It is well known that the high temperature strength and stability of an oxide dispersed alloy can be greatly improved by appropriate thermomechanical processing, but the mechanism of this strengthening effect is not well understood. This investigation was undertaken to study the dislocation substructures formed in beryllia dispersed nickel alloys as a function of cold work both with and without intermediate anneals. Two alloys, one Ni-lv/oBeo and other Ni-4.5Mo-30Co-2v/oBeo were investigated. The influence of the substructures produced by Thermo-Mechanical Processing (TMP) on the high temperature creep properties of these alloys was also evaluated.

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

2019 ◽  
pp. 43-48
Author(s):  
Ben Nengjun ◽  
Zhou Pengfei ◽  
Oleksandr Labartkava ◽  
Mykhailo Samokhin
Keyword(s):  
Rare Earth ◽  
High Temperature ◽  
Nickel Alloys ◽  
Total Content ◽  
Operating Conditions ◽  
High Temperature Strength ◽  
High Chromium ◽  
Salt Corrosion ◽  
Tcp Phases ◽  
The Impact

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.

Mechanism of formation and properties of aluminum coatings on high-temperature strength nickel alloys

1985 ◽  
Vol 27 (1) ◽  
pp. 24-28
Author(s):  
V. P. Lesnikov ◽  
V. P. Kuznetsov ◽  
M. V. Kukhtin ◽  
Yu. A. Belykh ◽  
Yu. O. Goroshenko
Keyword(s):  
High Temperature ◽  
Nickel Alloys ◽  
High Temperature Strength ◽  
Mechanism Of Formation ◽  
Aluminum Coatings

scholarly journals Modeling the Influence of the Composition of Refractory Elements on the Heat Resistance of Nickel Alloys by a Deep Learning Artificial Neural Network

2020 ◽  
Author(s):  
Dmitry TARASOV ◽  
Oleg Milder ◽  
Andrei Tiagunov
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Deep Learning ◽  
High Temperature ◽  
Nickel Alloys ◽  
Rupture Strength ◽  
Chemical Degradation ◽  
High Temperature Strength ◽  
Refractory Elements ◽  
Artificial Neural

Nickel alloys are widely used in the production of gas turbine parts. The alloys show resistance to mechanical and chemical degradation under severe long-term stress and high temperatures. One of the major mechanical properties of the alloys is the high-temperature rupture strength, which is measured after a specimen is heated to a certain temperature and held for a certain time considering deformation. Determining the influence of certain elements on the properties of an alloy is a complex scientific and engineering problem that affects the time and cost of developing new materials. Simulation is a great chance to cut costs. In this paper, we predict a high-temperature strength based on the composition of refractory elements in alloys using a deep learning artificial neural network. We build the model based on prior knowledge of the composition of the alloys, information on the role of alloying elements, type of crystallization, test temperature and time, and the tensile strength. Successful simulation results show the applicability of this method in practice.

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

2019 ◽  
pp. 48-54
Author(s):  
Ben Nengjun ◽  
Oleksandr Labartkava ◽  
Mykhailo Samokhin
Keyword(s):  
Rare Earth ◽  
High Temperature ◽  
Nickel Alloys ◽  
Total Content ◽  
Operating Conditions ◽  
High Temperature Strength ◽  
High Chromium ◽  
Salt Corrosion ◽  
Tcp Phases ◽  
The Impact

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.

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