Improved Performance Rhenium Containing Single Crystal Alloy Turbine Blades Utilizing PPM Levels of the Highly Reactive Elements Lanthanum and Yttrium

1999 ◽  
Vol 121 (1) ◽  
pp. 138-143 ◽  
Author(s):  
D. A. Ford ◽  
K. P. L. Fullagar ◽  
H. K. Bhangu ◽  
M. C. Thomas ◽  
P. S. Burkholder ◽  
...  
Keyword(s):  
Single Crystal ◽  
Volume Fraction ◽  
High Reliability ◽  
Turbine Blades ◽  
Engine Performance ◽  
Alumina Scale ◽  
Manufacturing Cost ◽  
Team Approach ◽  
Air Cooling ◽  
Scale Spallation

Turbine inlet temperatures have now approached 1650°C (3000°F) at maximum power for the latest large commercial turbofan engines, resulting in high fuel efficiency and thrust levels approaching or exceeding 445 kN (100,000 lbs.). High reliability and durability must be intrinsically designed into these turbine engines to meet operating economic targets and ETOPS certification requirements. This level of performance has been brought about by a combination of advances in air cooling for turbine blades and vanes, computerized design technology for stresses and airflow, and the development and application of rhenium (Re) containing, high γ’ volume fraction nickel-base single crystal superalloys, with advanced coatings, including prime-reliant ceramic thermal barrier coatings (TBCs). Re additions to cast airfoil superalloys not only improve creep and thermomechanical fatigue strength but also environmental properties, including coating performance. Re slows down diffusion in these alloys at high operating temperatures [1]. At high gas temperatures, several issues are critical to turbine engine performance retention, blade life, and integrity. These are tip oxidation in particular for shroudless blades, internal oxidation for lightly cooled turbine blades, and TBC adherence to both the airfoil and tip seal liner. It is now known that sulfur (S) at levels, <10 ppm but >0.2 ppm in these alloys reduces the adherence of α alumina protective scales on these materials or their coatings by weakening the Van der Waal’s bond between the scale and the alloy substrate. A team approach has been used to develop an improvement to CMSX-41 alloy which contains 3 percent Re, by reducing S and phosphorus (P) levels in the alloy to <2 ppm, combined with residual additions of lanthanum (La) + yttrium (Y) in the range 10-30 ppm. Results from cyclic, burner rig dynamic oxidation testing at 1093°C (2000°F) show thirteen times the number of cycles to initial alumina scale spallation for CMSX-4 [La + Y] compared to standard CMSX-4. A key factor for application acceptance is of course manufacturing cost. The development of improved low reactivity prime coats for the blade shell molds along with a viable, tight dimensional control yttrium oxide core body are discussed. The target is to attain grain yields of single crystal CMSX-4 (ULS) (La + Y) turbine blades and casting cleanliness approaching standard CMSX-4. The low residual levels of La + Y along with a sophisticated homogenisation/solutioning heat treatment procedure result in full solutioning with essentially no residual γ/γ’ eutectic phase, Ni (La, Y) low melting point eutectics, and associated incipient melting pores. Thus, full CMSX-4 mechanical properties are attained. The La assists with ppm chemistry control of the Y throughout the single crystal turbine blade castings through the formation of a continuous lanthanum oxide film between the molten and solidifying alloy and the ceramic core and prime coat of the shell mold. Y and La tie up the <2 ppm but >0.2 ppm residual S in the alloy as very stable Y and La sulfides and oxysulfides, thus preventing diffusion of the S atoms to the alumina scale layer under high temperature, cyclic oxidising conditions. La also forms a stable phosphide. CMSX-4 (ULS) (La + Y) HP shroudless turbine blades will commence engine testing in May 1998.

Improved Performance Rhenium Containing Single Crystal Alloy Turbine Blades Utilising PPM Levels of the Highly Reactive Elements Lanthanum and Yttrium

1998 ◽  
Author(s):  
David A. Ford ◽  
Keith P. L. Fullagar ◽  
Harry K. Bhangu ◽  
Malcolm C. Thomas ◽  
Phil S. Burkholder ◽  
...  
Keyword(s):  
Single Crystal ◽  
Volume Fraction ◽  
High Reliability ◽  
Turbine Blades ◽  
Engine Performance ◽  
Alumina Scale ◽  
Manufacturing Cost ◽  
Team Approach ◽  
Air Cooling ◽  
Scale Spallation

Turbine inlet temperatures have now approached 1650°C (3000°F) at maximum power for the latest large commercial turbofan engines, resulting in high fuel efficiency and thrust levels approaching or exceeding 445 kN (100,000 lbs.). High reliability and durability must be intrinsically designed into these turbine engines to meet operating economic targets and ETOPS certification requirements. This level of performance has been brought about by a combination of advances in air cooling for turbine blades and vanes, computerized design technology for stresses and airflow and the development and application of rhenium (Re) containing, high γ′ volume fraction nickel-base single crystal superalloys, with advanced coatings, including prime-reliant ceramic thermal barrier coatings (TBCs). Re additions to cast airfoil superalloys not only improve creep and thermo-mechanical fatigue strength but also environmental properties, including coating performance. Re slows down diffusion in these alloys at high operating temperatures.(1) At high gas temperatures, several issues are critical to turbine engine performance retention, blade life and integrity. These are tip oxidation in particular for shroudless blades, internal oxidation for lightly cooled turbine blades and TBC adherence to both the airfoil and tip seal liner. It is now known that sulfur (S) at levels < 10 ppm but > 0.2 ppm in these alloys reduces the adherence of α alumina protective scales on these materials or their coatings by weakening the Van der Waal’s bond between the scale and the alloy substrate. A team approach has been used to develop an improvement to CMSX-4® alloy which contains 3% Re, by reducing S and phosphorus (P) levels in the alloy to < 2 ppm, combined with residual additions of lanthanum (La) + yttrium (Y) in the range 10–30 ppm. Results from cyclic, burner rig dynamic oxidation testing at 1093°C (2000°F) show thirteen times the number of cycles to initial alumina scale spallation for CMSX-4 [La + Y] compared to standard CMSX-4. A key factor for application acceptance is of course manufacturing cost. The development of improved low reactivity prime coats for the blade shell molds along with a viable, tight dimensional control yttrium oxide core body are discussed. The target is to attain grain yields of single crystal CMSX-4 (ULS) [La + Y] turbine blades and casting cleanliness approaching standard CMSX-4. The low residual levels of La + Y along with a sophisticated homogenisation/solutioning heat treatment procedure result in full solutioning with essentially no residual γ/γ′ eutectic phase, Ni (La, Y) low melting point eutectics and associated incipient melting pores. Thus, full CMSX-4 mechanical properties are attained. The La assists with ppm chemistry control of the Y throughout the single crystal turbine blade castings through the formation of a continuous lanthanum oxide film between the molten and solidifying alloy and the ceramic core and prime coat of the shell mold. Y and La tie up the < 2 ppm but > 0.2 ppm residual S in the alloy as very stable Y and La sulfides and oxysulfides, thus preventing diffusion of the S atoms to the alumina scale layer under high temperature, cyclic oxidising conditions. La also forms a stable phosphide. CMSX-4 (ULS) [La + Y] HP shroudless turbine blades will commence engine testing in May 1998.

Development and Turbine Engine Performance of Three Advanced Rhenium Containing Superalloys for Single Crystal and Directionally Solidified Blades and Vanes

1997 ◽  
Author(s):  
Robert W. Broomfield ◽  
David A. Ford ◽  
Harry K. Bhangu ◽  
Malcolm C. Thomas ◽  
Donald J. Frasier ◽  
...  
Keyword(s):  
Single Crystal ◽  
High Reliability ◽  
Turbine Blades ◽  
Combined Cycle ◽  
Maximum Power ◽  
Team Approach ◽  
Air Cooling ◽  
Directionally Solidified ◽  
Turbine Engine ◽  
Nickel Base

Turbine inlet temperatures over the next few years will approach 1650°C (3000°F) at maximum power for the latest large commercial turbo fan engines, resulting in high fuel efficiency and thrust levels approaching 445 kN (100,000 lbs). High reliability and durability must be intrinsically designed into these turbine engines to meet operating economic targets and ETOPS certification requirements. This level of performance has been brought about by a combination of advances in air cooling for turbine blades and vanes, design technology for stresses and airflow, single crystal and directionally solidified casting process improvements and the development and use of rhenium (Re) containing high γ′ volume fraction nickel-base superalloys with advanced coatings, including full-airfoil ceramic thermal barrier coatings. Re additions to cast airfoil superalloys not only improve creep and thermo-mechanical fatigue strength but also environmental properties, including coating performance. Re dramatically slows down diffusion in these alloys at high operating temperatures. A team approach has been used to develop a family of two nickel-base single crystal alloys (CMSX-4® containing 3% Re and CMSX®−10 containing 6% Re) and a directionally solidified, columnar grain nickel-base alloy (CM 186 LC® containing 3% Re) for a variety of turbine engine applications. A range of critical properties of these alloys is reviewed in relation to turbine component engineering performance through engine certification testing and service experience. Industrial turbines are now commencing to use this aero developed turbine technology in both small and large frame units in addition to aero-derivative industrial engines. These applications are demanding, with high reliability required for turbine airfoils out to 25,000 hours, with perhaps greater than 50% of the time spent at maximum power. Combined cycle efficiencies of large frame industrial engines is scheduled to reach 60% in the U.S. ATS programme. Application experience to a total 1.3 million engine hours and 28,000 hours individual blade set service for CMSX-4 first stage turbine blades is reviewed for a small frame industrial engine.

Development and Turbine Engine Performance of Three Advanced Rhenium Containing Superalloys for Single Crystal and Directionally Solidified Blades and Vanes

1998 ◽  
Vol 120 (3) ◽  
pp. 595-608 ◽  
Author(s):  
R. W. Broomfield ◽  
D. A. Ford ◽  
J. K. Bhangu ◽  
M. C. Thomas ◽  
D. J. Frasier ◽  
...  
Keyword(s):  
Single Crystal ◽  
High Reliability ◽  
Turbine Blades ◽  
Combined Cycle ◽  
Maximum Power ◽  
Team Approach ◽  
Air Cooling ◽  
Directionally Solidified ◽  
Turbine Engine ◽  
Nickel Base

Turbine inlet temperatures over the next few years will approach 1650°C (3000°F) at maximum power for the latest large commercial turbofan engines, resulting in high fuel efficiency and thrust levels approaching 445 KN (100,000 lbs.). High reliability and durability must be intrinsically designed into these turbine engines to meet operating economic targets and ETOPS certification requirements. This level of performance has been brought about by a combination of advances in air cooling for turbine blades and vanes, design technology for stresses and airflow, single crystal and directionally solidified casting process improvements, and the development and use of rhenium (Re) containing high γ′ volume fraction nickel-base superalloys with advanced coatings, including full-airfoil ceramic thermal barrier coatings. Re additions to cast airfoil superalloys not only improves creep and thermo-mechanical fatigue strength, but also environmental properties including coating performance. Re dramatically slows down diffusion in these alloys at high operating temperatures. A team approach has been used to develop a family of two nickel-base single crystal alloys (CMSX-4® containing 3 percent Re and CMSX®-10 containing 6 percent Re) and a directionally solidified, columnar grain nickel-base alloy (CM 186 LC® containing 3 percent Re) for a variety of turbine engine applications. A range of critical properties of these alloys is reviewed in relation to turbine component engineering performance through engine certification testing and service experience. Industrial turbines are now commencing to use this aero developed turbine technology in both small and large frame units in addition to aero-derivative industrial engines. These applications are demanding, with high reliability required for turbine airfoils out to 25,000 hours, with perhaps greater than 50 percent of the time spent at maximum power. Combined cycle efficiencies of large frame industrial engines are scheduled to reach 60 percent in the U. S. ATS programme. Application experience to a total 1.3 million engine hours and 28,000 hours individual blade set service for CMSX-4 first stage turbine blades is reviewed for a small frame industrial engine.

CMSX®-486: A New Grain Boundary Strengthened Single Crystal Superalloy

2002 ◽  
Author(s):  
Ken Harris ◽  
Jacqueline B. Wahl
Keyword(s):  
Grain Boundary ◽  
Single Crystal ◽  
Engine Performance ◽  
Single Crystal Superalloy ◽  
Manufacturing Cost ◽  
Application Development ◽  
Turbine Engine ◽  
Component Design ◽  
Casting Yield ◽  
Rupture Properties

Modern turbine engine performance and life cycle requirements demand single crystal superalloy turbine airfoil and seal components. Complex SX vane segments can result in severe manufacturing cost challenges. This has resulted in the development of an improved creep-rapture strength SX superalloy designated CMSX®-486. This alloy is grain boundary strengthened through optimised additions of boron, carbon, hafnium and zirconium and is designed for use as-cast, to maximise complex casting yield through the use of generous grain specifications and without solution heat treatment recrystallisation problems. The paper in particular gives comprehensive low and high angle boundary creep-rupture properties of CMSX-486, enabling grain specifications to be developed depending upon component design requirements. The alloy has now entered its turbine application development phase.

Investigation on Stress and Strain of Ni-Based Single Crystal Super-Alloy Specimen with Single Hole Based on Abacus

2021 ◽  
Vol 891 ◽  
pp. 17-22
Author(s):  
Xiang Zhen Xue ◽  
Zhi Xun Wen ◽  
Wen Xian Li
Keyword(s):  
Fatigue Life ◽  
Single Crystal ◽  
High Reliability ◽  
Turbine Blades ◽  
High Strength ◽  
Initial Crack ◽  
Alloy Specimen ◽  
Single Hole ◽  
Stress Ratios ◽  
Super Alloy

The Miss stress, Max.principal strain and Magnitude displacement have important influence on the fatigue life of the Ni-based single crystal super-alloy turbine blades. This work investigated The Miss stress, Max.principal strain and Magnitude displacement of Ni-based single crystal super-alloy specimen with single hole along dangerous path under different working conditions by Abacus. The results show that the initial crack length and loading stresses are larger, the crack growth on the specimen is faster, and then, the fatigue life is the shorter. Moreover, for the different stress ratios, smaller stress ratio can lead to lower fatigue life. The result is significant to design turbine of Ni-based single crystal super-alloy of high accuracy, high reliability and high strength.

CMSX-486® Single Crystal Alloy: Production Experience and Development of an Improved Version

2006 ◽  
Author(s):  
Jacqueline B. Wahl ◽  
Ken Harris
Keyword(s):  
Single Crystal ◽  
Rupture Strength ◽  
Engine Performance ◽  
Manufacturing Cost ◽  
Creep Rupture Strength ◽  
Turbine Engine ◽  
Production Experience ◽  
Casting Yield ◽  
Oxidation Resistant ◽  
Manufacturing Yield

Modern turbine engine performance and life cycle requirements demand single crystal (SX) superalloy turbine airfoil and seal components. However, complex SX components, such as vane segments, can result in severe manufacturing cost challenges due to low manufacturing yield. These requirements led to the development of CMSX-486® alloy, a grain boundary strengthened SX superalloy with improved creep-rupture strength over SX CM 186 LC® alloy. CMSX-486 alloy has excellent casting yield achieved through generous grain inspection criteria and is used as-cast, which minimizes post-cast processing costs and eliminates the risk of recrystallization during solution heat treatment. CMSX-486 alloy has attained production status and further improvements to the alloy are under evaluation. This paper will review the unique properties which make this alloy of serious interest, with particular attention to ongoing production experience. Discussion will also include direction and results of an improved oxidation resistant version of CMSX-486 alloy which is currently under development.

Creep and Thermomechanical Fatigue Modelling of Single Crystal Superalloy Turbine Blades

2001 ◽  
Author(s):  
M. B. Henderson ◽  
T. J. Ward ◽  
G. F. Harrison ◽  
M. Hughes
Keyword(s):  
Single Crystal ◽  
Turbine Blades ◽  
Engine Performance ◽  
Complex Loading ◽  
Inelastic Strain ◽  
Fatigue Behaviour ◽  
Thermomechanical Fatigue ◽  
Rotor Blades ◽  
Linear Deformation ◽  
Anisotropic Creep

Gas turbine engine rotor blades are being manufactured increasingly from nickel-based single crystal superalloys. Intended for use in the hottest sections of the turbine, these alloys are capable of providing large increases in component endurance and reliability, as well as engine performance due to increased turbine entry temperature levels. To ensure full utilisation and calculation of safe component life times, accurate modelling of the non-linear deformation suffered during typical duty cycles is needed. The Mechanical Sciences Sector at DERA, Farnborough has developed an anisotropic creep analysis and modelling capability specifically targeted at simulating the high temperature creep and thermomechanical fatigue behaviour of superalloy single crystal specimens and turbine blades under complex loading and non-isothermal conditions. The model has been incorporated into a user material subroutine (UMAT) for use with the ABAQUS finite element programme, within which the inelastic strain is considered to be a combination of the instantaneous plastic strains, time-dependent creep strains and thermal strains. A recent collaborative programme between Alstom Power (UK) and DERA has applied this model to generate predictions for the anisotropic creep and thermomechanical fatigue behaviour of a number of specimen and blade designs.

Thermo-Mechanical Fatigue Experiments of Single Crystal Hollow Turbine Blades

2012 ◽  
Author(s):  
Fulei Jing ◽  
Rongqiao Wang ◽  
Dianyin Hu
Keyword(s):  
Temperature Distribution ◽  
Stress Distribution ◽  
Single Crystal ◽  
Turbine Blades ◽  
Experimental System ◽  
Critical Section ◽  
Air Cooling ◽  
Laboratory Environment ◽  
Mechanical Fatigue ◽  
Loading Device

The thermo-mechanical fatigue (TMF) experiments have been performed on the critical section of single crystal hollow turbine blades. An experimental system was constructed for the TMF experiments. A special loading device was designed and machined for the blades to provide loading conditions and simulate the stress distribution on the critical section. Induction heating and air cooling were utilized to provide anisothermal conditions. A new induction coil was designed to satisfy the requirements of the temperature distribution on the critical section. This TMF experimental system provided evidence that the loading and anisothermal conditions experienced by the turbine blades during service could be reproduced in a laboratory environment.

Study of single crystal turbine blades made of ZhS32 alloy with a promising scheme of cooling

2018 ◽  
Vol 84 (10) ◽  
pp. 35-40
Author(s):  
E. V. Kolyadov ◽  
L. I. Rassohina ◽  
E. M. Visik ◽  
V. V. Gerasimov ◽  
E. V. Filonova
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Volume Fraction ◽  
Turbine Blades ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Machine Building ◽  
Single Crystal Structure ◽  
Metallographic Analysis ◽  
X Ray

The results of studying single-crystal turbine blades with a promising scheme of cooling, cast from a heat-resistant ZhS32 alloy using ceramic rods with high-temperature sintering additives and additional impregnation with a varnish solution are presented. The program of crystallizing blades with a single-crystal structure is improved on a VIP-NK installation. A comparison of the operation modes of the updated program and serial technology is presented. A pilot batch of blade castings is obtained under production conditions of a machine-building enterprise with an output suitable in single-crystal structure of about 94%. Blade castings are studied using X-ray diffraction, X-ray and ultrasound methods. Quantitative metallographic analysis is carried out on an optical complex to determine spacing between axes of the first order dendrites (λ1) of the alloy and the volume fraction of the micropores in the cross section of the pen and casting lock. The results of scanning electron microscopy study of macro-and microstructure of the blade castings with a promising cooling scheme showed that the structure is typical for ZhS32alloy in the cast state and is well formed in the elements of the inner cavity of monocrystalline blades.

Chemical partitioning of elements in Ni-base MC-carbide reinforced eutetic superalloys

1983 ◽  
Vol 41 ◽  
pp. 250-251
Author(s):  
E. F. Koch ◽  
E. L. Hall ◽  
S. W. Yang
Keyword(s):  
Alloy Composition ◽  
Volume Fraction ◽  
Lattice Mismatch ◽  
Turbine Blades ◽  
Eutectic Alloys ◽  
Alloy Matrix ◽  
X Ray ◽  
Gas Turbine Blades ◽  
Analytical Electron ◽  
Analytical Electron Microscope

The plane-front solidified eutectic alloys consisting of aligned tantalum monocarbide fibers in a nickel alloy matrix are currently under consideration for future aircraft and gas turbine blades. The MC fibers provide exceptional strength at high temperatures. In these alloys, the Ni matrix is strengthened by the precipitation of the coherent γ' phase (ordered L12 structure, nominally Ni3Al). The mechanical strength of these materials can be sensitively affected by overall alloy composition, and these strength variations can be due to several factors, including changes in solid solution strength of the γ matrix, changes in they γ' size or morphology, changes in the γ-γ' lattice mismatch or interfacial energy, or changes in the MC morphology, volume fraction, thermal stability, and stoichiometry. In order to differentiate between these various mechanisms, it is necessary to determine the partitioning of elemental additions between the γ,γ', and MC phases. This paper describes the results of such a study using energy dispersive X-ray spectroscopy in the analytical electron microscope.

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