Interdiffusion Databanks of γ, γ′ and β Phases in NiAl-Based Ternary Systems

2017 ◽  
Vol 13 ◽  
pp. 136-166 ◽  
Author(s):  
Li Jun Zhang ◽  
Juan Chen ◽  
Wei Min Chen ◽  
Na Ta ◽  
Qin Li

Advanced modern gas-turbine engines strongly rely on high-temperature thermal barrier coatings (TBCs) for the improved efficiency and power. Interdiffusion between the bond coat and the underlying Ni-based superalloy is one key factor limiting the lifetime of TBCs. In order to assist the engineering-oriented lifetime assessment and even design new TBCs, reliable composition- and temperature-dependent interdiffusivity databanks for γ, γ′ and β phases in different types of bond coats and Ni-based superalloys are the prerequisite. This chapter starts from a very brief introduction of the state-of-art experimental techniques and calculation methods for interdiffusivity determination in ternary systems. After that, the status of the interdiffusion databanks of γ, γ′ and β phases in NiAl-based ternary systems is then summarized, with a special focus on the demonstration of interdiffusivity data measured by means of single-phase diffusion couple/multiple techniques in combination with Matano-Kirkaldy method or numerical inverse method. Several typical results for NiAl-based γ, γ′ and β phases are also given. Finally, two examples of successful applications of the available interdiffusion databanks of ternary NiAl-based γ, γ′ and β phases are presented. One lies in the Re-substitutional element searching in potential new-generation Ni-based superalloys, while the other is the phase-field modeling of interdiffusion microstructure in ternary mode NiAlCr-based TBCs without/with the effect of temperature gradient.

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4214
Author(s):  
Kranthi Kumar Maniam ◽  
Shiladitya Paul

The increased demand for high performance gas turbine engines has resulted in a continuous search for new base materials and coatings. With the significant developments in nickel-based superalloys, the quest for developments related to thermal barrier coating (TBC) systems is increasing rapidly and is considered a key area of research. Of key importance are the processing routes that can provide the required coating properties when applied on engine components with complex shapes, such as turbine vanes, blades, etc. Despite significant research and development in the coating systems, the scope of electrodeposition as a potential alternative to the conventional methods of producing bond coats has only been realised to a limited extent. Additionally, their effectiveness in prolonging the alloys’ lifetime is not well understood. This review summarises the work on electrodeposition as a coating development method for application in high temperature alloys for gas turbine engines and discusses the progress in the coatings that combine electrodeposition and other processes to achieve desired bond coats. The overall aim of this review is to emphasise the role of electrodeposition as a potential cost-effective alternative to produce bond coats. Besides, the developments in the electrodeposition of aluminium from ionic liquids for potential applications in gas turbines and the nuclear sector, as well as cost considerations and future challenges, are reviewed with the crucial raw materials’ current and future savings scenarios in mind.


Author(s):  
John Blouch ◽  
Hejie Li ◽  
Mark Mueller ◽  
Richard Hook

The LM2500 and LM6000 dry-low-emissions aeroderivative gas turbine engines have been in commercial service for 15 years and have accumulated nearly 10 × 106 hours of commercial operation. The majority of these engines utilize pipeline quality natural gas predominantly comprised of methane. There is; however, increasing interest in nonstandard fuels that contain varying levels of higher hydrocarbon species and/or inert gases. This paper reports on the demonstrated operability of LM2500 and LM6000 DLE engines with nonstandard fuels. In particular, rig tests at engine conditions were performed to demonstrate the robustness of the dual-annular counter-rotating swirlers premixer design, relative to flameholding with fuels containing high ethane, propane, and N2 concentrations. These experiments, which test the ability of the hardware to shed a flame introduced into the premixing region, have been used to expand the quoting limits for LM2500 and LM6000 gas turbine engines to elevated C2+ levels. In addition, chemical kinetics analysis was performed to understand the effect of temperature, pressure, and fuel compositions on flameholding. Test data for different fuels and operating conditions were successfully correlated with Damkohler number.


Author(s):  
John Blouch ◽  
Hejie Li ◽  
Mark Mueller ◽  
Richard Hook

The LM2500 and LM6000 dry-low-emissions (DLE) aeroderivative gas turbine engines have been in commercial service for 15 years and have accumulated nearly 10 million hours of commercial operation. The majority of these engines utilize pipeline quality natural gas predominantly comprised of methane. There is, however, increasing interest in nonstandard fuels that contain varying levels of higher hydrocarbon species and/or inert gases. This paper reports on the demonstrated operability of LM2500 and LM6000 DLE engines with nonstandard fuels. In particular, rig tests at engine conditions were performed to demonstrate the robustness of the dual-annular counter-rotating swirlers (DACRS) premixer design, relative to flameholding with fuels containing high ethane, propane, and N2 concentrations. These experiments, which test the ability of the hardware to shed a flame introduced into the premixing region, have been used to expand the quoting limits for LM2500 and LM6000 gas turbine engines to elevated C2+ levels. In addition, chemical kinetics analysis was performed to understand the effect of temperature, pressure, and fuel compositions on flameholding. Test data for different fuels and operating conditions were successfully correlated with Damkohler number.


Author(s):  
W. T. Bakker ◽  
D. Kotchick

Utilizing dirty fuels such as coal in gas turbine engines requires that heat input to the cycle working fluid occur through a heat exchanger. For high cycle efficiencies such a heat exchanger must operate in the 700–1400 KPA, 1100–1200°C (100–200 psi, 2000–2200°F) range. In this temperature range, ceramic heat exchangers are required. Ceramic heat exchangers that can operate in this regime have been under development for several years on a very modest scale. These programs are briefly reviewed. Major material issues are reviewed and the status of each is presented. Mechanical reliability and joining technology have been successfully demonstrated in short term tests. Long-term durability and the manufacturing technology to produce large scale components reproducibly remains to be demonstrated in the future.


Author(s):  
Americo Bonafede ◽  
Dennis Russom ◽  
Matthew Driscoll

This paper discusses the common threads that have been gleaned by the Navy in having operated many different gas turbine engines in a marine environment for nearly thirty years. The status of the Navy’s Honeywell TF40B, Rolls Royce 501 and General Electric LM2500 gas turbine engine programs is discussed.


Author(s):  
Victor I. Romanov

This paper describes design features and performance data of the ГТД 8000 and ГТД 15000 engines of new generation. The efficiency of these engines is 34–35% (simple cycle, ISO Conditions). The paper presents basic trends of design and technology improvements resulted in a high performance engine. Examples of new gas turbines application are shown.


2007 ◽  
Vol 546-549 ◽  
pp. 1277-1280
Author(s):  
Yue Feng Gu ◽  
C. Cui ◽  
D. Ping ◽  
Hiroshi Harada ◽  
Akihiro Sato ◽  
...  

A new kind of cast & wrought (C&W) Ni-Co base superalloys named as “TMW alloys” was developed recently for compressor and turbine disk of gas turbine engines in the High Temperature Materials 21 Project at the National Institute for Materials Science (NIMS) in Japan. These Ni-Co base superalloys combine the characters of two kinds of γ- γ’ two-phase alloys (Ni-base and Co-base superalloys) and can be fabricated by cheap cast and wrought processing route. The results showed that some of these TMW alloys have superior tensile strength at temperatures up to 750 °C and higher creep resistances up to 725 °C than commercial UDIMET 720 LI alloy.


Author(s):  
J. M. Delimont ◽  
M. K. Murdock ◽  
W. F. Ng ◽  
S. V. Ekkad

When gas turbine engines operate in environments where the intake air has some concentration of particles, the engine will experience degradation. Very few studies of such microparticles approaching their melting temperatures are available in open literature. The coefficient of restitution (COR), a measure of the particles' impact characteristics, was measured in this study of microparticles using a particle tracking technique. Part II of this study presents data taken using the Virginia Tech Aerothermal Rig and Arizona road dust (ARD) of 20–40 μm size range. Data were taken at temperatures up to and including 1323 K, where significant deposition of the sand particles was observed. The velocity at which the particles impact the surface was held at a constant 70 m/s for all of the temperature cases. The target on which the particles impacted was made of a nickel alloy, Hastelloy X. The particle angle of impact was also varied between 30 deg and 80 deg. Deposition of particles was observed as some particles approach their glass transition point and became molten. Other particles, which do not become molten due to different particle composition, rebounded and maintained a relatively high COR. Images were taken using a microscope to examine the particle deposition that occurs at various angles. A rebound ratio was formulated to give a measure of the number of particles which deposited on the surface. The results show an increase in deposition as the temperature approaches the melting temperature of sand.


1997 ◽  
Vol 28 (7-8) ◽  
pp. 536-542
Author(s):  
A. A. Khalatov ◽  
I. S. Varganov

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