scholarly journals Hot Deformation of Cast and Extruded TiAl: An In Situ Diffraction Study

2012 ◽  
Vol 706-709 ◽  
pp. 1725-1730 ◽  
Author(s):  
Thomas Schmoelzer ◽  
Klaus Dieter Liss ◽  
Svea Mayer ◽  
Kun Yan ◽  
Mark Reid ◽  
...  
Keyword(s):  
Hot Deformation ◽  
Turbine Blades ◽  
Diffraction Method ◽  
Production Costs ◽  
Microstructural Development ◽  
Jet Engines ◽  
Tial Alloys ◽  
Low Pressure Turbine ◽  
High Temperature Materials

Intermetallic TiAl alloys are a class of innovative high-temperature materials which are developed to replace the substantially denser Ni-base alloys in low-pressure turbine blades of jet engines. By streamlining the production process of these parts, a substantial decrease in production costs can be achieved. To this end, a profound knowledge of the microstructural processes occurring during hot deformation is a prerequisite. To investigate the microstructural development during forming operations, cast and extruded as well as only cast specimens were hot-deformed and the microstructural development investigated in-situ by means of a novel diffraction method. This powder diffraction method utilizes the behavior of individual reflection spots on the Debye-Scherrer rings for deriving the materials response to the deformation imposed. It was found that the behavior of the two specimens is rather similar, although the starting microstructures show pronounced differences.

The Use of In Situ Characterization Techniques for the Development of Intermetallic Titanium Aluminides

2014 ◽  
Vol 783-786 ◽  
pp. 2097-2102 ◽  
Author(s):  
Svea Mayer ◽  
Emanuel Schwaighofer ◽  
Martin Schloffer ◽  
Helmut Clemens
Keyword(s):  
Titanium Aluminides ◽  
Turbine Blades ◽  
Heat Treatments ◽  
Mechanical Processing ◽  
Tial Alloys ◽  
Solidification Processes ◽  
Consistent Picture ◽  
Aero Engines ◽  
Multi Phase

Urgent needs concerning energy efficiency and environmental politics require novel approaches to materials design. One recent example is thereby the implementation of light-weight intermetallic titanium aluminides as structural materials for the application in turbine blades of aero-engines as well as in turbocharger turbine wheels for the next generation of automotive engines. Each production process leads to specific microstructures which can be altered and optimized by thermo-mechanical processing and / or subsequent heat-treatments. To develop sound and sustainable processing routes, knowledge on solidification processes and phase transformation sequences in advanced TiAl alloys is fundamental. Therefore, in-situ diffraction techniques employing synchrotron radiation and neutrons were used for establishing phase fraction diagrams, investigating advanced heat-treatments as well as for optimizing thermo-mechanical processing. Summarizing all results a consistent picture regarding microstructure formation and its impact on mechanical properties in advanced multi-phase TiAl alloys can be given.

The Science, Technology, and Implementation of TiAl Alloys in Commercial Aircraft Engines

2013 ◽  
Vol 1516 ◽  
pp. 49-58 ◽  
Author(s):  
B. P. Bewlay ◽  
M. Weimer ◽  
T. Kelly ◽  
A. Suzuki ◽  
P.R. Subramanian
Keyword(s):  
Titanium Aluminide ◽  
Turbine Blades ◽  
Aircraft Engine ◽  
Low Pressure ◽  
Major Advance ◽  
Commercial Aircraft ◽  
Tial Alloys ◽  
Low Pressure Turbine ◽  
Titanium Aluminide Alloy ◽  
History Of

ABSTRACTThe present article will describe the science and technology of titanium aluminide (TiAl) alloys and the engineering development of TiAl for commercial aircraft engine applications. The GEnxTM engine is the first commercial aircraft engine that is flying titanium aluminide (alloy 4822) blades and it represents a major advance in propulsion efficiency, realizing a 20% reduction in fuel consumption, a 50% reduction in noise, and an 80% reduction in NOx emissions compared with prior engines in its class. The GEnxTM uses the latest materials and design processes to reduce weight, improve performance, and reduce maintenance costs.GE’s TiAl low-pressure turbine blade production status will be discussed along with the history of implementation. In 2006, GE began to explore near net shape casting as an alternative to the initial overstock conventional gravity casting plus machining approach. To date, more than 40,000 TiAl low-pressure turbine blades have been manufactured for the GEnxTM 1B (Boeing 787) and the GEnxTM 2B (Boeing 747-8) applications. The implementation of TiAl in other GE and non-GE engines will also be discussed.

New Developments in High Temperature Materials 21 Project in Japan

2005 ◽  
Author(s):  
Hiroshi Harada ◽  
Junzo Fujioka
Keyword(s):  
High Temperature ◽  
Thermal Efficiency ◽  
Gas Turbines ◽  
Power Plants ◽  
Turbine Blades ◽  
Combined Cycle ◽  
Jet Engines ◽  
High Temperature Materials ◽  
Design Program ◽  
Temperature Capability

Following the Kyoto Conference on Climate Change (COP3) held in 1997, the improvement of thermal efficiency in power engineering systems is becoming a major issue. In High Temperature Materials 21 Project at NIMS, materials for turbine blades and vanes are being developed to improve the temperature capability and reduce the CO2 emission of industrial gas turbines (IGT) and jet engines. The target for Ni-base superalloys was set at 1100°C for 1000h creep rupture life under 137MPa to realize ultra-efficient combined cycle power plants and advanced jet engines. A high cost-performance single crystal (SC) superalloy TMS-82+ with 1075°C temperature capability has been developed and tested in a 15MW IGT. A 4th generation SC superalloy TMS-138 exhibiting 1080°C temperature capability has also been developed and tested in a 1650°C test jet engine. TMS-138 is to be applied in the Japanese eco-engine project for 50-seater jet airplanes. A further control of the interfacial dislocation network resulted in a 5th generation SC alloy TMS-162 with 1105°C temperature capability. A virtual gas turbine (VT), which is a combination of materials design program and system design program, is being developed and becoming a powerful tool as an interface between material scientists and system engineers. Using VT, air-cooled blades with our SC superalloys have been evaluated up to 1700°C gas temperature, and a substantial improvement in thermal efficiency of a combined-cycle power generation system has been indicated.

In Situ Synthesis of TiAl Matrix Composites by Melting Route

2007 ◽  
Vol 345-346 ◽  
pp. 1221-1224
Author(s):  
Bong Jae Choi ◽  
Si Young Sung ◽  
Young Jig Kim
Keyword(s):  
Optical Microscope ◽  
Matrix Composites ◽  
Tial Alloys ◽  
Specific Strength ◽  
Electron Probe Micro Analyzer ◽  
Arc Melting ◽  
High Temperature Materials ◽  
Oxidation Ratio ◽  
Base Superalloy

TiAl alloys Al composition range between 45 and 49 at%, includes γ-TiAl and α2-Ti3Al, are an emerging high temperature materials which has higher specific strength, oxidation ratio and specific modulus than Ni base superalloy. In this study, TiAl alloys were manufactured by plasma arc melting (PAM) and then TiAl and granular boron carbide were in-situ synthesized in PAM method again. The in-situ synthesized TiAl matrix composites were investigated by using X-ray diffractometer, optical microscope, and electron probe micro-analyzer.

In Situ Eddy-Current Testing on Low-Pressure Turbine Blades of Aircraft Engine

2012 ◽  
Vol 40 (4) ◽  
pp. 103388
Author(s):  
Gong-Jin Qi ◽  
Hong Lei ◽  
Gang-Qiang Fu ◽  
Peng Jing ◽  
Jun-Ming Lin
Keyword(s):  
Eddy Current ◽  
Turbine Blades ◽  
Aircraft Engine ◽  
Low Pressure ◽  
Eddy Current Testing ◽  
Current Testing ◽  
Low Pressure Turbine

Cracks on the Roots of Turbine Blades of the Low-Pressure Turbine in a Steam Power Plant

2015 ◽  
Vol 52 (4) ◽  
pp. 214-225 ◽  
Author(s):  
E. Plesiutschnig ◽  
R. Vallant ◽  
G. Stöfan ◽  
C. Sommitsch ◽  
M. Mayr ◽  
...  
Keyword(s):  
Power Plant ◽  
Turbine Blades ◽  
Low Pressure ◽  
Steam Power ◽  
Steam Power Plant ◽  
Low Pressure Turbine

scholarly journals Additive Manufacturing of Ti-Based Intermetallic Alloys: A Review and Conceptualization of a Next-Generation Machine

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4317
Author(s):  
Thywill Cephas Dzogbewu ◽  
Willie Bouwer du Preez
Keyword(s):  
Heat Treatment ◽  
High Temperature ◽  
Additive Manufacturing ◽  
Complex Geometries ◽  
Intermetallic Alloys ◽  
Tial Alloys ◽  
Conventional Methods ◽  
Manufacturing Technologies ◽  
In Situ Heat Treatment

TiAl-based intermetallic alloys have come to the fore as the preferred alloys for high-temperature applications. Conventional methods (casting, forging, sheet forming, extrusion, etc.) have been applied to produce TiAl intermetallic alloys. However, the inherent limitations of conventional methods do not permit the production of the TiAl alloys with intricate geometries. Additive manufacturing technologies such as electron beam melting (EBM) and laser powder bed fusion (LPBF), were used to produce TiAl alloys with complex geometries. EBM technology can produce crack-free TiAl components but lacks geometrical accuracy. LPBF technology has great geometrical precision that could be used to produce TiAl alloys with tailored complex geometries, but cannot produce crack-free TiAl components. To satisfy the current industrial requirement of producing crack-free TiAl alloys with tailored geometries, the paper proposes a new heating model for the LPBF manufacturing process. The model could maintain even temperature between the solidified and subsequent layers, reducing temperature gradients (residual stress), which could eliminate crack formation. The new conceptualized model also opens a window for in situ heat treatment of the built samples to obtain the desired TiAl (γ-phase) and Ti3Al (α2-phase) intermetallic phases for high-temperature operations. In situ heat treatment would also improve the homogeneity of the microstructure of LPBF manufactured samples.

scholarly journals Towards Damage Controlled Hot Forming

2018 ◽  
Vol 885 ◽  
pp. 56-63
Author(s):  
Markus Bambach ◽  
Irina Sizova ◽  
Aliakbar Emdadi
Keyword(s):  
Metal Forming ◽  
High Performance ◽  
Titanium Aluminides ◽  
Turbine Blades ◽  
Process Time ◽  
Jet Engines ◽  
Internal Damage ◽  
Creep Properties ◽  
Recent Developments ◽  
Ram Speed

Metal forming processes may induce internal damage in the form of voids in the workpiece under unfavorable deformation conditions. Controlling the amount of damage induced by metal forming operations may increase service performance of the produced parts. Damage is crucial in high-performance components of limited workability such as jet engine turbine blades. Recent developments have introduced forged titanium aluminides into commercial jet engines. Titanium aluminides are lightweight intermetallic compounds with excellent creep properties but very limited ductility. Their low workability requires isothermal forging at slow strain rates, which is typically kept constant in the process. This work explores the possibility of increasing the ram speed during the process so that the process time is reduced while the amount of damage introduced into the workpiece is controlled. The results show that a 25% reduction in process time seems viable without increase in damage by solving an optimal control problem, in which the ram speed profile is determined off-line by minimization.

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