Aero Engine Test Experience With CMSX-4® Alloy Single-Crystal Turbine Blades

1996 ◽  
Vol 118 (2) ◽  
pp. 380-388 ◽  
Author(s):  
K. P. L. Fullagar ◽  
R. W. Broomfield ◽  
M. Hulands ◽  
K. Harris ◽  
G. L. Erickson ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Single Crystal ◽  
Turbine Blade ◽  
Hot Corrosion ◽  
Turbine Blades ◽  
Casting Process ◽  
Creep Rupture ◽  
Coating Performance ◽  
Turbine Engine ◽  
Mechanical Fatigue

A team approach involving a turbine engine company (Rolls-Royce), its single-crystal casting facilities, and a superalloy developer and ingot manufacturer (Cannon-Muskegon), utilizing the concepts of simultaneous engineering, has been used to develop CMSX-4 alloy successfully for turbine blade applications. CMSX-4 alloy is a second-generation nickel-base single-crystal superalloy containing 3 percent (wt) rhenium (Re) and 70 percent volume fraction of the coherent γ′ precipitate strengthening phase. Its finely balanced composition offers an attractive range of properties for turbine airfoil applications. In particular the alloy’s combination of high strength in relation to creep-rupture, mechanical and thermal fatigue, good phase stability following extensive high temperature, stressed exposure and oxidation, hot corrosion and coating performance, are attractive for turbine engine applications where engine performance and turbine airfoil durability are of prime importance. The paper details the single-crystal casting process and heat treatment manufacturing development for turbine blades in CMSX-4 alloy. Competitive single-crystal casting yields are being achieved in production and extensive vacuum heat treatment experience confirms CMSX-4 alloy to have a practical production solution heat treat/homogenization “window.” The creep-rupture data-base on CMSX-4 alloy now includes 325 data points from 17 heats including 3630 kg (8000 lb) production size heats. An appreciable portion of this data was machined-from-blade (MFB) properties, which indicate turbine blade component capabilities based on single-crystal casting process, component configuration, and heat treatment. The use of hot isostatic pressing (HIP) has been shown to eliminate single-crystal casting micropores, which along with the essential absence of γ/γ′ eutectic phase, carbides, stable oxide, nitride and sulfide inclusions, results in remarkably high mechanical fatigue properties, with smooth and particularly notched specimens. The Re addition has been shown not only to benefit creep and mechanical fatigue strength (with and without HIP), but also bare oxidation, hot corrosion (sulfidation), and coating performance. The high level of balanced properties determined by extensive laboratory evaluation has been confirmed during engine testing of the Rolls-Royce Pegasus turbofan.

scholarly journals Aero Engine Test Experience With CMSX-4® Alloy Single Crystal Turbine Blades

1994 ◽  
Author(s):  
Keith P. L. Fullagar ◽  
Robert W. Broomfield ◽  
Mark Hulands ◽  
Ken Harris ◽  
Gary L. Erickson ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Single Crystal ◽  
Turbine Blade ◽  
Hot Corrosion ◽  
Turbine Blades ◽  
Casting Process ◽  
Creep Rupture ◽  
Coating Performance ◽  
Turbine Engine ◽  
Mechanical Fatigue

A team approach involving a turbine engine company [Rolls-Royce], its single crystal casting facilities and a superalloy developer and ingot manufacturer [Cannon-Muskegon], utilizing the concepts of simultaneous engineering, has been used to successfully develop CMSX-4 alloy for turbine blade applications. CMSX-4 alloy is a second generation nickel-base single crystal superalloy containing 3% (wt) rhenium (Re) and 70% volume fraction of the coherent γ′ precipitate strengthening phase. Its finely balanced composition offers an attractive range of properties for turbine airfoil applications. In particular the alloy’s combination of high strength in relation to creep-rupture, mechanical and thermal fatigue, good phase stability following extensive high temperature, stressed exposure and oxidation, hot corrosion and coating performance, are attractive for turbine engine applications where engine performance and turbine airfoil durability are of prime importance. The paper details the single crystal casting process and heat treatment manufacturing development for turbine blades in CMSX-4 alloy. Competitive single crystal casting yields are being achieved in production and extensive vacuum heat treatment experience confirms CMSX-4 alloy to have a practical production solution heat treat / homogenization “window”. The creep-rupture data-base on CMSX-4 alloy now includes 325 data points from seventeen heats including fourteen 3630 kg (8000 lb) production size heats. An appreciable portion of this data was machined-from-blade (MFB) properties which indicate turbine blade component capabilities based on single crystal casting process, component configuration and heat treatment. The use of hot-isostatic-pressing (HIP) has been shown to eliminate single crystal casting micropores which along with the essential absence of γ/γ′ eutectic phase, carbides, stable oxide, nitride and sulphide inclusions results in remarkably high mechanical fatigue properties, with smooth and particularly notched specimens. The Re addition has been shown to not only benefit creep and mechanical fatigue strength (with and without HIP), but also bare oxidation, hot corrosion (sulphidation) and coating performance. The high level of balanced properties determined by extensive laboratory evaluation has been confirmed during engine testing the Rolls-Royce Pegasus turbofan.

scholarly journals Applying Protective Coating on the Turbine Engine Turbine Blades by Means of Plasma Spraying

2020 ◽  
Vol 50 (1) ◽  
pp. 193-213
Author(s):  
Leszek Ułanowicz ◽  
Andrzej Dudziński ◽  
Paweł Szczepaniak ◽  
Mirosław Nowakowski
Keyword(s):  
Heat Treatment ◽  
Service Life ◽  
Plasma Spraying ◽  
Turbine Blade ◽  
Protective Coating ◽  
Turbine Blades ◽  
Thermal Spraying ◽  
Jet Engine ◽  
Turbine Engine ◽  
Spraying Process

AbstractThe tendency to increase the temperature of gases and the desire to extend the service life forces the use of a protective coating on the blade. The publication presents the technology of applying a heat-resistant protective coating onto the jet engine turbine blade by means of plasma thermal spraying, taking into account the process of aluminizing and heat treatment after aluminizing. The paper presents the results of work on the possibilities of shaping the thickness of the protective coating on the blade by changing the parameters of the spraying process, such as spraying distance, amount of hydrogen, amount of argon and the number of torch passes.

scholarly journals Development of the Single Crystal Alloys CM SX-2 and CM SX-3 for Advanced Technology Turbine Engines

1983 ◽  
Author(s):  
K. Harris ◽  
G. L. Erickson ◽  
R. E. Schwer
Keyword(s):  
Heat Treatment ◽  
Single Crystal ◽  
Turbine Blade ◽  
Solution Heat Treatment ◽  
Creep Rupture ◽  
Advanced Technology ◽  
Thin Wall ◽  
Incipient Melting ◽  
Practical Solution ◽  
Oxidation And Corrosion

Two complementary single crystal alloys have been developed from the MAR-M-247 composition, with the objectives of providing high creep-rupture strength, excellent oxidation resistance, good castability, practical solution heat-treatment ranges, high incipient melting points, and stable microstructures. The alloys, CM SX-2 and CM SX-3, are turbine blade and vane alloys, with CM SX-3 showing improved coated oxidation and corrosion resistance. Foundry performance characteristics studied using ten different single crystal casting processes to produce both solid and complex cored, thin-wall turbine blade and vane components were: “freckling” sensitivity, spurious grain formation, microporosity, and alloy/ceramic core reactions. Practical solution heat-treatment ranges (difference between the γ′ solvus and the incipient melting temperatures) have been established and vary from 45–50°F for CM SX-3 and 50–55°F for CM SX-2 measured without prior homogenization treatments. Extensive machined-from-blade (MFB) mechanical property work is reported. Alloy stability investigations were undertaken using prior tested MFB stress-rupture specimens. Environmental evaluations using both bare and coated single crystal specimens, subjected to separate cyclic/dynamic oxidation, and corrosion testing in burner-type rigs are also reviewed. A new γ′ microstructure/heat-treatment technology has been found to be particularly applicable to CM SX-2 and CM SX-3 alloys, because of their low γ/γ′ mismatch and suitable γ′ chemistry. This technology further increases the creep-rupture capability of both alloys by 10–40°F, depending on test temperature.

The Influence of Crystal Orientation on the Elastic Stresses of a Single Crystal Nickel-Based Turbine Blade

2011 ◽  
Vol 134 (1) ◽  
Author(s):  
Michael W. R. Savage
Keyword(s):  
Single Crystal ◽  
Turbine Blade ◽  
Fatigue Resistance ◽  
Crystal Orientation ◽  
Turbine Blades ◽  
Casting Process ◽  
Directionally Solidified ◽  
Element Analysis ◽  
Angle Variation ◽  
Elastic Stresses

Single crystal nickel-based turbine blades are directionally solidified during the casting process with the crystallographic direction [001] aligned with the blade stacking axis. This alignment is usually controlled within 10 deg, known as the Primary angle. The rotation of the single crystal about the [001] axis is generally not controlled and this is known as the Secondary angle. The variation in Primary and Secondary angles relative to the blade geometry means that the stress response from blade to blade will be different, even for the same loading conditions. This paper investigates the influence of single crystal orientation on the elastic stresses of a CMSX-4 turbine blade root attachment using finite element analysis. The results demonstrate an appreciable variation in elastic stress when analyzed over the controlled Primary angle, and are further compounded by the uncontrolled Secondary angle. The maximum stress range will have a direct impact on the fatigue resistance of the turbine blade. By optimizing the Secondary angle variation the elastic stresses can be reduced, giving the potential to enhance the fatigue resistance of the turbine blade.

The Influence of Crystal Orientation on the Elastic Stresses of a Single Crystal Nickel-Based Turbine Blade

2011 ◽  
Author(s):  
Michael W. R. Savage
Keyword(s):  
Single Crystal ◽  
Turbine Blade ◽  
Fatigue Resistance ◽  
Crystal Orientation ◽  
Turbine Blades ◽  
Casting Process ◽  
Directionally Solidified ◽  
Element Analysis ◽  
Angle Variation ◽  
Elastic Stresses

Single crystal nickel-based turbine blades are directionally solidified during the casting process with the crystallographic direction [001] aligned with the blade stacking axis. This alignment is usually controlled within 10°, known as the Primary angle. The rotation of the single crystal about the [001] axis is generally not controlled and this is known as the Secondary angle. The variation in Primary and Secondary angles relative to the blade geometry means that the stress response from blade to blade will be different, even for the same loading conditions. This paper investigates the influence of single crystal orientation on the elastic stresses of a CMSX-4 turbine blade root attachment using finite element analysis. The results demonstrate an appreciable variation in elastic stress when analysed over the controlled Primary angle, and are further compounded by the uncontrolled Secondary angle. The maximum stress range will have a direct impact on the fatigue resistance of the turbine blade. By optimizing the Secondary angle variation the elastic stresses can be reduced, giving the potential to enhance the fatigue resistance of the turbine blade.

scholarly journals Comprehensive report on Materials for Gas Turbine Engine Components

2019 ◽  
Vol 9 (2S2) ◽  
pp. 155-158
Keyword(s):  
Gas Turbine ◽  
Turbine Blade ◽  
Thermal Stresses ◽  
Prolonged Exposure ◽  
Raw Materials ◽  
Turbine Blades ◽  
Gas Turbine Engine ◽  
Operating Conditions ◽  
Turbine Engine ◽  
Engine Component

In the past three decades, it is very challenging for the researchers to design and development a best gas turbine engine component. Engine component has to face different operating conditions at different working environments. Nickel based superalloys are the best material to design turbine components. Inconel 718, Inconel 617, Hastelloy, Monel and Udimet are the common material used for turbine components. Directional solidification is one of the conventional casting routes followed to develop turbine blades. It is also reported that the raw materials are heat treated / age hardened to enrich the desired properties of the material implementation. Accordingly they are highly susceptible to mechanical and thermal stresses while operating. The hot section of the turbine components will experience repeated thermal stress. The halides in the combination of sulfur, chlorides and vanadate are deposited as molten salt on the surface of the turbine blade. On prolonged exposure the surface of the turbine blade starts to peel as an oxide scale. Microscopic images are the supportive results to compare the surface morphology after complete oxidation / corrosion studies. The spectroscopic results are useful to identify the elemental analysis over oxides formed. The predominant oxides observed are NiO, Cr2O3, Fe2O3 and NiCr2O4. These oxides are vulnerable on prolonged exposure and according to PB ratio the passivation are very less. In recent research, the invention on nickel based superalloys turbine blades produced through other advanced manufacturing process is also compared. A summary was made through comparing the conventional material and advanced materials performance of turbine blade material for high temperature performance.

Rejuvenation Heat Treatment of Single Crystal Gas Turbine Blades

2017 ◽  
Author(s):  
J. Kuipers ◽  
K. Wiens ◽  
B. Ruggiero
Keyword(s):  
Heat Treatment ◽  
Single Crystal ◽  
Gas Turbine ◽  
Turbine Blades ◽  
Damage Mechanism ◽  
Operating Conditions ◽  
Gas Turbine Blades ◽  
Full Solution ◽  
Fatigue Endurance ◽  
Root Surfaces

Thermal degradation of precipitation-hardened nickel based superalloys has been demonstrated to be reversible through full solution rejuvenation heat treatment processing. The specific concern with full solution rejuvenation heat treatment of single crystal alloys is the formation of recrystallized grains on surfaces with residual stress. The threshold temperature for recrystallization and the effect of heat treatment temperature and time on recrystallization depth were evaluated on service run industrial gas turbine blades comprised of nickel based single crystal alloys René N5 and RR2000. Recrystallization of rejuvenated blades was observed on the root surfaces of blades which had been shot peened at original manufacture and/or during a prior repair. Blades which did not receive peening at manufacture were free of recrystallization in critical areas following full solution rejuvenation heat treatment. Given that gas turbine blade roots operate at relatively low temperatures compared to the airfoil, creep is not considered a life limiting damage mechanism for this region of the blade. Rather, high cycle fatigue is considered the primary damage mechanism of concern. As such, fatigue testing of shot peened and heat treated (recrystallized) René N5 specimens was carried out at 650°C at various stress levels in comparison with baseline (non-recrystallized) specimens to determine the extent to which recrystallization would limit fatigue endurance at blade root operating conditions. It was found that recrystallization did not reduce the fatigue endurance relative to baseline samples at the tested conditions. The findings indicate that repair including full solution rejuvenation heat treatment of previously peened blades comprised of René N5 alloy is feasible provided that recrystallization be limited to root surfaces.

scholarly journals Development of a High-Efficiency Z-Form Selector for Single Crystal Blades and Corresponding Grain Selection Mechanism

Materials ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 780 ◽  
Author(s):  
Xintao Zhu ◽  
Fu Wang ◽  
Dexin Ma ◽  
Andreas Bührig-Polaczek
Keyword(s):  
Single Crystal ◽  
High Efficiency ◽  
Geometrical Structure ◽  
Turbine Blades ◽  
Grain Structure ◽  
Two Dimensional ◽  
Coating Properties ◽  
Turbine Engine ◽  
Research Material ◽  
Super Alloy

Single crystal (SX) is widely used in modern turbine blades to improve the creep fracture, fatigue, oxidation, and coating properties of the turbine, so that the turbine engine has excellent performance and durability. In this paper, the single crystal super alloy MM247LC is used as the research material. The evolution of grain structure in a two-dimensional grain selector was studied by directional experiments, and the mechanism of grain selection in the two-dimensional channel during directional solidification was clarified. In order to optimize the production process of single crystal turbine blades, the effects of the geometrical structure of a Z-type separator (i.e., wire diameter and take-off angle) on the crystal orientation, microstructure, and grain efficiency of blades were discussed.

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