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.

scholarly journals Using a Three-Dimensional Reduction Method in the High-Efficiency Grain Selector and Corresponding Grain Selection Mechanism

Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1781
Author(s):  
Xintao Zhu ◽  
Fu Wang ◽  
Shuaipeng Zhang ◽  
Tobias Wittenzellner ◽  
Jessica Frieß ◽  
...  
Keyword(s):  
Single Crystal ◽  
High Efficiency ◽  
Turbine Blades ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Two Dimensional ◽  
Selection Mechanism ◽  
Dimensional Reduction Method ◽  
Optimization Parameters ◽  
Dimensional Coupling

In the development of a high-efficiency grain selector, the spiral selectors are widely used in Ni-based single crystal (SX) superalloys casting to produce single crystal turbine blades. For the complex three-dimensional structure of the spiral, a 2D grain selector was designed to investigate in this paper. As a result, the parameters of two-dimensional grain selection bond and the corresponding grain selection mechanism were established, and the three-dimensional grain selection bond was designed again by means of two-dimensional coupling optimization parameters.

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.

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.

scholarly journals 2-D Selector Simulation Studies on Grain Selection for Single Crystal Superalloy of CM247LC

Materials ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 3829
Author(s):  
Hang Zhang ◽  
Xintao Zhu ◽  
Fu Wang ◽  
Dexin Ma
Keyword(s):  
Single Crystal ◽  
Texture Evolution ◽  
Single Crystal Superalloy ◽  
Two Dimensional ◽  
Simulation Studies ◽  
Research Material ◽  
Single Crystal Turbine Blade ◽  
Selection For ◽  
Stray Grain ◽  
Cellular Automaton Finite Element

In the present work, the single crystal superalloy CM247LC was selected as the research material. By using directional experiments and the cellular automaton finite element (CAFE) model, the process of grain texture evolution in a two-dimensional grain selector was investigated to clarify the mechanism of grain selection in the two-dimensional passage during the process of directional solidification (DS). To optimize single crystal turbine blade production processes, the effects of grain selector geometries (i.e., selector diameter and pitch length, take-off angle) on the microstructure and stray grain were simulated and discussed.

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.

scholarly journals Grain Selection in a High-Efficiency 2D Grain Selector During Casting of Single-Crystal Superalloys

Materials ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 789 ◽  
Author(s):  
Xintao Zhu ◽  
Fu Wang ◽  
Dexin Ma ◽  
Andreas Bührig-Polaczek
Keyword(s):  
Single Crystal ◽  
Optical Microscopy ◽  
High Efficiency ◽  
Two Dimensional ◽  
Competitive Growth ◽  
Electron Backscattered Diffraction ◽  
Single Grain ◽  
Eccentric Distance

Using electron backscattered diffraction techniques (EBSD) and optical microscopy (OM), the grain selection and competitive growth in a new-designed high-efficiency two-dimensional (2D) selector during solidification of Ni-based single-crystal (SX) superalloys have been investigated with emphasis on the geometry of the selector part in this article. It is found that the efficiency of the grain selector depends greatly on the thickness and eccentric distance of the selector part. When the thickness is smaller than 3 mm, a single grain can be selected. After reducing this value, the grain selector becomes more effective. When the eccentric distance is larger than 8 mm, one grain can be selected. As the eccentric distance increases, the selector’s efficiency is optimized. Recommendations for optimizing the geometry of the selector part are provided.

Development of Nickel Based Superalloys for Advanced Turbine Engines

2014 ◽  
Vol 783-786 ◽  
pp. 2491-2496 ◽  
Author(s):  
Andrzej Nowotnik ◽  
Krzysztof Kubiak ◽  
Jan Sieniawski ◽  
Paweł Rokicki ◽  
Paweł Pędrak ◽  
...  
Keyword(s):  
Single Crystal ◽  
High Performance ◽  
Structural Changes ◽  
Turbine Blades ◽  
Diffraction Method ◽  
Turbine Engines ◽  
Secondary Phases ◽  
Turbine Engine ◽  
Cast Alloys ◽  
Bridgeman Method

Superalloys have been developed for specific, dedicated properties and applications. One of the main application for this material is advanced, high-performance aircraft engines elements. Turbine engine creates harsh environments for materials due to the high operating temperature and stress level. Hence, as described in this article, many alloys used in the turbine section of these engines are very complex and highly optimized. This article provides an overview of structural changes that occur during the aging process of wrought and cast alloys and provides insight into the use of precipitated particles to achieve desired structures. Example will focus on alloy Inconel 718 and CMSX-4. Functional properties of these alloys can be achieved by choosing proper heat treatment parameters to obtain required rate between secondary phases. The paper also attempts to determine structural perfection and changes of crystallographic orientation along the axis of growth of single crystal nickel superalloys cast using X-ray topography and Laue diffraction method. Single crystal bars and turbine blades were manufactured in VIM furnace using the Bridgeman method. Withdrawing rates typical for CMSX-4 superalloy were used. It has been found that with increasing withdrawing rate the nature of distribution along the axis of growth of the angle of [001] direction deviation from the axis of single crystal blades growth had changed. The change of the withdrawing rate results also in the rotation of γ’ phase in the form of cubes against the axis of single crystal blades growth.

Evaluation of 1700C Class Turbine Blades in Hydrogen Fueled Combustion Turbine System

2000 ◽  
Author(s):  
Takanari Okamura ◽  
Akinori Koga ◽  
Shoko Itoh ◽  
Hiroyuki Kawagishi
Keyword(s):  
Heat Transfer ◽  
Wind Tunnel ◽  
Single Crystal ◽  
Transfer Test ◽  
Rotor Blade ◽  
Turbine Blades ◽  
Cooling Effectiveness ◽  
Cooling Method ◽  
Hybrid Cooling ◽  
Super Alloy

This paper describes the cooling design and experimental evaluations of the 1700C class turbine blades in hydrogen fueled combustion turbine system. The hybrid cooling method combining recovery steam cooling with partial film cooling was chosen based on a careful study on several cooling systems from the viewpoint of plant efficiency and durability of turbine blades. In the development process, high temperature cooled turbine blades, the advanced cooling technologies, single crystal super alloy and thermal barrier coating (TBC) are important issues to be paid attention and following experiments were performed. First, outer heat transfer test on stator blade and internal heat transfer test in ribbed channel for cooling rotor blade were carried out using liquid crystal thermography. The cooling effectiveness of rotor blade was further investigated in steam driven wind tunnel. The characteristics of single crystal super alloy and TBC were also evaluated in hot steam environment. As a next step, the scale model test blades of size nearly one half to that of the first stage stator and rotor blades in actual turbine were designed and manufactured. Finally, the turbine blade cascade tests were conducted using hydrogen-oxygen combustion driven wind tunnel under practical hot steam conditions of 1700C and 2.5MPa. In these experiments, cooling effectiveness, metal temperatures and cooling steam flow characteristics were investigated. After completing all the test runs, the robustness of blade substrate and TBC were inspected. The experimental results on the hybrid cooling method and blade design procedures are discussed.

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.

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