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90431 Nürnberg

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Phone: +49 (0)911 9315-92

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Member of

Advanced Metallurgical Group N.V.

4th INTERNATIONAL WORKSHOP

ON TITANIUM ALUMINIDES

September 13th - 16th, 2011, Nuremberg, GERMANY

Sponsored by

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4th International Workshop on Titanium Aluminides, Nuremberg 2011

4th International Workshop on Titanium Aluminides September 13th – 16th, 2011, Nuremberg, Germany

CONTENTS page

Program Summary 2

Wednesday Morning 3 Wednesday Afternoon 4 Wednesday Poster Presentation 5 Thursday Morning 6 Thursday Afternoon 7

Friday Morning 8 Friday Afternoon 9

Titles and Abstracts

1. Alloy Development 10 2. Fundamental Understanding 11 3. Properties and Applications 17 4. Primary Processing 23 5. Secondary Processing 27 6. Coating / environmental protection 30 7. Poster Presentation 34

List of Attending Organizations 40 List of Participants 42

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Final Program Summary Tuesday, September 13th, 2011 04.00 – 07:00 pm Registration at NH Hotel Nuremberg City 07:00 – 11:00 pm Welcome Reception at NH Hotel Nuremberg City

sponsored by GfE Metalle und Materialien GmbH

08:00 – 08:15 pm Opening remarks by Dr. Ernst Wallis (Managing Director GfE) Wednesday, September 14th, 2011 08:30 am – 05.00pm Oral Presentations (NH Hotel Nuremberg City)

□ Alloy Development □ Fundamental Understanding □ Properties and Applications

05:00 – 06:00 pm Short oral introduction of posters Thursday, September 15th, 2011 08:30 am – 04:15 pm Oral presentations (NH Hotel Nuremberg City)

□ Properties and Applications □ Primary Processing

04:30 – 04:45 pm Bus transfer to GfE 04:45 – 06:30 pm GfE plant tour 06:30 – 06:45 pm Bus transfer to NH Hotel Nuremberg City 07:00 – 07:30 pm City sight walks to the Bavarian Workshop Dinner at the Nuremberg Old City 07:30 Workshop Dinner sponsored by Böhler Schmiedetechnik GmbH & Co. KG DTF Technology GmbH Leistritz Turbinenkomponenten Remscheid GmbH TITAL GmbH Rolls Royce Deutschland GmbH Friday, September 16th, 2011 08:30 am – 03:00 pm Oral presentations (NH Hotel Nuremberg City)

□ Primary Processing □ Secondary Processing □ Coating / environmental protection

03:00 – 03:10 pm Closing Remarks

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Technical Program Wednesday, September 14th, 2011 - Morning Session Chairman: Helmut Clemens

No. Time Topic Titel and Authors

1.1 08:30-08:55 am

Alloy Development

Development of TiAl alloy with high creep strength and manufacturability for a turbine wheel

Yoshihiko Koyanagi, Shigeki Ueta and Toshiharu Noda Daido Corp., Japan

1.2 08:55-09:20 am

Alloy Development

Development of a Nb-free titanium aluminide intermetallics with a low-temperature superplasticity

Yong Liu, Congzhang Qiu, Wei Zhang and Bin Liu Central South University, Hunan, P.R. China

1.3 09:20-09:45 am

Alloy Development

Development of TiAl alloys by spark plasma sintering containig heavy elements

Alain Couret, Houria Jabbar and Jean-Philippe Monchoux CEMES/CNRS, Toulouse, France

2.1 09:45-10:10 am

Fundamental Understanding

The contribution of high-energy X-rays and neutrons to characterization and development of intermetallic titanium aluminides

Thomas Schmölzer, Klaus-Dieter Liss, Peter Staron, Svea Mayer and Helmut Clemens Montanuniversität Leoben, Austria

10:10-10:30 am Coffee Break

2.2 10:30-11:00 am


INVITED PRESENTATIONIn-situ observation of cracking behavior and toughening in fully lamellar TiAl alloys

Masao Takeyama, Y Imai and T. Kigugawa Tokyio Institute of Technology, Japan

2.3 11:00-11:25 am


Effect of the beta/alpha transformation on the microstructure in gamma TiAl alloys

Michael Oehring, Andreas Stark, Jonathan Paul and Florian Pyczak Helmholtz-Zentrum Geesthacht, Germany

2.4 11:25-11:50 am


Effect of microstructure on hot deformability of TiAl alloys Keiji Kubushiro, Satoshi Takahashi, Keiko Morishima, Mikiya

Arai and Masao Takeyama IHI Corporation Japan,

2.5

11:50-12:15 pm


On the quaternary phase diagram TiAl-Nb-Mo

Martin Schloffer, Emanuel Schwaighofer, Albert Themeßl, Helmut Clemens, Falko Heutling, Dietmar Helm, Matthias Achtermann, Svea Mayer

Department of Physical Metallurgy and Materials Testing, Montanuniversität Leoben

12:15 - 13:15 pm Lunch Break

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Technical Program Wednesday, September 14th, 2011 - Afternoon Session Chairman: Masao Takeyama

No. Time Topic Titel and Authors 2.6 01:15-

01:40 pm Fundamental Understanding

Transformation kinetics in Al-rich Ti-Al Martin Palm, Nico Engberding, Frank Stein, Stefan Irsen and

Klemens Klemm MPIE Düsseldorf, Germany

2.7 01:40-02:05 pm


Deformation mechanisms of PST TiAl under various strain conditions

Kyosuke Kishida, Kengo Goto and Haruyuki Inui Kyoto University, Japan

2.8 02:05-02:30 pm


Hardening and softening during aging in a nano-lamellar TiAl alloy with coherent or semicoherent interfaces

Kouichi Maruyama, Takehiro Kamei and Junya Nakamura Tohoku University, Japan

2.9 02:30-02:55 pm


Microstructure evolution during solidification and solid phase transformations in TiAl-based alloy

Juraj Lapin, Katarína Frkáňová and Zuzana Gabalcová

Institute of Materials and Machine Mechanics, Slovak Academy of Sciences

2.10

02:55-03:20 pm


Factors influencing slip in alpha 2 in TiAl-based alloys

Michael Loretto and Hamish Fraser IRC Birmingham, UK

03:20 - 03:40 pm Coffee Break

3.1 03:40-04:10 pm

Properties and Applications

INVITED PRESENTATIONApplication of gamma TiAl to automotive aftermarket turbocharger

David Decker BorgWarner, USA

3.2 04:10-04:35 pm


A comparative study of cyclic strain hardening and fatigue life in two PM Ti-48Al-2Cr-2Nb alloys

Marc Thomas, O. Berteaux, R. Valle, M. Raffestin, M. Jouiad and G. Hénaff ONERA, France

3.3 04:35-05:00 pm


Microstructure and mechanical properties of a forged new beta-phase containing gamma titanium aluminide alloy

Janny Lindemann, Sebastian Bolz, Michael Oehring, Florian Pyczak and Dan Roth-Fagaraseanu Technical University of Cottbus, Germany

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Technical Program Wednesday, September 15th, 2011 – Poster Presentation

05:00-06:00 pm Short oral introduction of Posters (3 min each) - Posters remain accessible during the entire workshop -

P1 Axial-torsional thermo-mechanical fatigue of a near-

gamma TiAl-alloy S. Brookes, H.-J. Kühn1, B. Skrotzki, R. Sievert,

H. Klingelhöffer

BAM Federal Institute for Materials Research and Testing

P2 Protective Coatings for TiAl-alloys – PowderProduction and Thermal Spraying

Florian Pyczak, Jonathan Paul, Frank Peter Schimansky, Gerhard Wolf, Nicole Mehrl and Martin Faulstich

Helmholtz-Zentrum Geesthacht

P3 Linking microstructural and mechanical properties on different length scales for near g-TiAl alloys

Klemens Kelm, Mohammad Rizviul Kabir, Liudmila Chernova, Marion Bartsc1 and Nikolay Zotov German Aerospace Center

P4 Thermodynamic assessment of the Ti-Al-Nb, Ti-Al-Cr, and Ti-Al-Mo systems

Mario Kriegel, Damian M. Cupid, Olga Fabrichnaya, Hans J. Seifert Technische Universität Bergakdemie Freiberg, Institut für Werkstoffwissenschaft

P5 Thermomechanical fatigue behavior of the γ-TiAl based alloy TNB-V5

Markus Hoffmann, Marcel Roth and Horst BiermannInstitut für Werkstofftechnik, TU Bergakademie Freiberg

P6 Solidification behaviour of TiAl-based alloys Zuzana Gabalcová, Juraj Lapin

Institute of Materials and Machine Mechanics Slovak Academy of Sciences

P7 Beam welding and brazing of γ-titanium aluminide for linear and circumferential joints

Uwe Reisgen, Simon Olschok, Alexander Backhaus ISF - Welding and Joining Institute, RWTH Aachen University

P8 Environmental protection capability of different coating systems deposited on gamma titanium aluminides

Reinhold Braun, Christoph Leyens, Papken Eh. Hovsepian, Arutiun P. Ehiasarian, Maik Fröhlich DLR – German Aerospace Center, Institute of Materials Research

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Technical Program Thursday, September 15th, 2011 - Morning Session Chairman: Wilfried Smarsly


09:00 amProperties and Applications

INVITED PRESENTATIONMaterials for next generation commercial aircraft engines

Francis Preli Pratt&Whitney, USA

3.5 09:00-09:25 am


Assessment of fatigue sensitivity to defects of TiAl alloy produced by Electron Beam Melting (EBM)

Mauro Filippini, Stefano Beretta, Luca Patriarca, Giuseppe Pasquero and Silvia Sabbadini Politecnico di Milano, Italy

3.6 09:25-09:50 am


Mechanical behaviour of Ti-46Al-Ta alloy

Jurai Lapin, Oto Bajana and Tatiana Pelachová Slovak Academy of Sciences, Slovakia

3.7 09:50-10:15 am


Isothermal low-cycle and thermo-mechanical fatigue of a high-strength multiphase titanium aluminide alloy

Ali El-Chaikh, Thomas Heckel, Hans Jürgen Christ and Fritz Appel University of Siegen, Germany


3.8 10:35-11:05 am


INVITED PRESENTATIONMeasure of Gamma Ti Aluminide for aero-engine application

Mikiya Arai and Keiji Kubushiro IHI Corporation, Japan

3.9 11:05-11:30 am


Development of gamma TiAl for aerospace engines

Gopal Das, Wilfried Smarsly, F. Heutling, U. Habe, C. Kunze, and D. Helm

Pratt&Whitney, USA

3.10

11:30-11:55 am


An in-situ SEM evaluation of the elevated-temperature tensile and creep deformation behavior of Ti-45Al-2Mn-2Nb-XD

Rocío Muñoz Moreno, E.M. Ruiz-Navas, J.LLorca, M.T. Perez-Prado and C.J. Boehlert Madrid Institute for Advanced Studies of Materials, Spain

11:55-12:55 pm Lunch Break

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Technical Program Thursday, September 15th, 2011 – Afternoon Session Chairman: Michael Weimer


01:25 pm Primary Processing

INVITED PRESENTATIONInvestment cast TiAl LPT blades

Paul McQuay PCC Structurals, USA

4.2 01:25-01:50 pm

Primary Processing

High niobium containing TiAl alloy produced by electron beam melting

Sara Biamino, Mathieu Terner, Andrea Penna, Ulf Ackelid, Silvia Sabbadini, Paolo Fino, Matteo Pavese and Claudio Badini Politecnico di Torino, Italy

4.3 01:50-02:15 pm

Primary Processing

Difficulties in the up-scaling of γ-TiAl Component Size – a Novel Solution

Jonathan Paul, Uwe Lorenz, Michael Oehring, and Fritz Appel Helmholtz-Zentrum Geesthacht, Germany

4.4 02:15-02:40 pm

Primary Processing

Oxygen removal from molten TiAl based scrap by metallothermic reduction

Bernd Friedrich, Jan Reitz, Claus Lochbichler, Jan Christoph Stoephasius, Peter Spiess, Marek Bartosinski IME Process Metallurgy and Metal Recycling, RWTH Aachen University

02:40-03:00 pm Coffee Break

4.5 03:00-03:25 pm

Primary Processing

Solidification process of Ti4522XD

David Hu, Chao Yang and Ulrike Hecht IRC Birmingham, UK

4.6 03:25-03:50 pm

Primary Processing

Near conventional hot-die forging of a b-stabilized g-TiAl based alloy in an industrial scale

Daniel Huber, Esther Berhuber, Helmut Clemens and Volker Güther Böhler Schmiedetechnik, Austria

4.7 03:50-04:15 pm

Primary Processing

Production of g-TiAl based feed stock materials for subsequent investment casting and forging operations

Matthias Achtermann, Volker Güther and Hans-Peter Nicolai GfE Metalle und Materialien, Germany

04:30-06:30 pm GfE Plant Tour

07:30 pm Workshop Dinner

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Technical Program Friday, September 16th, 2011 – Morning Session Chairman: Marc Thomas


09:00 amPrimary Processing

INVITED PRESENTATIONSingle piece flow LPT blade casting development at GE Aviation Deutschland

Michael Weimer, Bernhard Bewlay and Tobias Schubert GE Aviation, Germany

5.1 09:00-09:25 am

Secondary Processing

Microstructural optimization of a cast and hot-isostatically pressed TNM alloy by heat treatment

Emanuel Schwaighofer, Martin Schloffer, Thomas Schmoelzer, Svea Mayer, Janny Lindemann, Volker Guether and Helmut Clemens Montanuniversität Leoben, Austria

5.2 09:25-09:50 am


Supercast Titanium -TiAL - material for the automotive and aerospace sector and its processing

Hans Billhofer Linn High term, Germany

5.3 09:50-10:15 am


Vacuum furnace concepts for Titanium Aluminides

Pavel Seserko, U. Betz, B. Sehring and T. Ruppel ALD Vacuum Technologies, Germany


5.4 10:35-11:00 am


Selective laser melting of Titanium Aluminides

Lukas Löber, Denis Klemm, Uta Kühn and Jürgen Eckert IFW Dresden, Germany

5.5 11:00-11:25 am


Interference-fit Joint of TiAl Rotor to Steel Shaft

Ji Zhang CISRI, P.R. China

5.6 11:25-11:50 am


Friction welding and laser beam welding of TNM-based TiAl joints with regeneration of microstructure by heat treatment

Heidi Cramer, Ludwig Appel and Peter Limley SLV München, Germany

6.1 11:50-12:15 pm

Coating / environmental protection

A "coating by design" approach applied to the optimisation of an Au coated Ti-48Al-2Cr-2Nb alloy

Jean-Francois Caudrelier, M-P. Bacos and M. Thomas ONERA, France

12:15 - 01:15 pm Lunch Break

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Technical Program Friday, September 16th, 2011 – Afternoon Session Chairman: Volker Güther


01:45 pm Coating / environmental protection

INVITED PRESENTATION Recent advances in the understanding of the halogen effect for oxidation protection of TiAl

Michael Schütze, Alexander Donchev and Simone Friedle DECHEMA, Germany

6.3 01:45-02:10 pm


Oxidation protection of TiAl alloys by plasma-based ion implantation of fluorine

Rossen Yankov, Andreas Kolitsch, Johannes von Borany, Frans Munnik, Arndt Mücklich, Alexander Donchev and Michael Schütze Helmholtz-Zentrum Dresden-Rossendorf, Germany

6.4 02:10-02:35 pm


Characterisation of oxidation protective coatings for titanium aluminides

Laurent Bortolotto, Cecile Langlade, Bernadeta Pelic, David Rafaja, Michael Schütze, Hans Jürgen Seifert, Gerhard Wolf and Patrick J. Masset DECHEMA, Germany

6.5 02:35-03:00 pm


ACETAL project: recent progress on the development of advanced coatings for titanium aluminides

Patrick Masset Freiberg University of Mining and Technology, Germany

03:00-03:10 pm Closing Remarks

Volker Güther Manager Advanced Materials GfE Metalle und Materialien GmbH

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4th International Workshop on Titanium Aluminides – Oral Session 1.1 Development of TiAl alloy with high creep strength and manufacturability

for a turbine wheel Yoshihiko Koyanagi1, Shigeki Ueta2 and Toshiharu Noda2 1Daido Castings Corp., Ltd., 1642-144 NASUBIGAWA, NAKATSUGAWA-SHI, GIFU, JAPAN 2Daido Steel Corp., Ltd., 2-30 DAIDO-CHO, MINAMI-KU, NAGOYA, JAPAN Abstract TiAl alloy has been already recognized to be adequate for a turbine wheel of turbocharger in both gasoline and diesel engines owing to the lightweight heat-resistance materials. So far the TiAl turbine wheels have been applied to general passenger vehicles and produced more than 120,000 pieces since 1998. In order to achieve the practical use of the TiAl wheels, comprehensive development of the engineering technologies which were alloy design, melting and casting process, and joining method with the steel shaft were considerably important. Recently exhaust gas temperature of the gasoline engines is rising to over 1000oC to improve the fuel consumption and to reduce toxic gas by stoichiometric combustion. Therefore endurable TiAl alloy for the turbine wheels of turbocharger in the new regulation gasoline engines which have higher strength and oxidation resistance at high temperature than the our developed commercial TiAl alloy (DAT-TA1:Ti-33Al-5Nb-1Cr-0.2Si) are required. A newly developed DAT-TA2 (Ti-31Al-8Nb-1Cr-0.5Si-0.03C) has good high temperature properties, so that it is expected to apply to the turbine wheels in the new regulation gasoline engines. And the manufacturability of DAT-TA2 for turbine wheels is comparable with the conventional production. The turbine wheels made of the new alloy are currently under evaluation by some users and the expected results are being gotten. 1.2 Development of a Nb-free TiAl-based intermetallics with a low-

temperature superplasticity Yong Liu, Congzhang Qiu, Bin Liu, Wei Zhang, Xiaopeng Liang State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, P.R.China Abstract TiAl-based intermetallics are promising materials for high temperature structural applications. In order to make complex-shaped parts, the hot workability is very essential. Currently, most TiAl-based intermetallics contain Nb, which is helpful for increasing high temperature oxidation resistance and creep strength. However, there are some difficulties in casting large ingots due to severe segregations. In this presentation, we studied the possibility for developing TiAl-based intermetallics without Nb element. Instead, Fe and Mo are alloyed with TiAl intermetallics. The results indicate that the TiAl-Fe-Mo intermetallics show a (B2+α2+γ) three-phase microstructures. The amount of β(B2) phase is increased with the increasing content of alloying elements, and Mo shows a higher stability for B2 phase than Fe does. The Microstructures are significantly refined to about 10 μm by additions of Fe and Mo. By screening the microstructures, a nominal composition of Ti-45Al-3Fe-2Mo (at. %), was selected for further study on the superplastic behaviors. The TiAl-based intermetallics shows a high ductility at 750 °C and a superplastic behavior at 790 °C. The dynamic recrystallization of β(B2) phase and grain boundary gliding of α2 or γ phases are two main acting mechanisms for the superplastic behavior of TiAl-based intermetallics at low temperatures. The new-composition TiAl-based intermetallics can be easily forged and rolled

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at 1250 °C without canning, and thus, can be considered as a basic intermetallics for further improvements in high temperature performance. This research was sponsored by the National High-tech Research and Development Program of China (Grant No. 2008AA03A233) and the National Basic Research Program of China ( Grant No. 2008AA03A233). 1.3 Development of TiAl Alloys containing refractory elements by spark

plasma sintering Alain Couret, Houria Jabbar and Jean-Philippe Monchoux , CEMES/CNRS, 29 Rue J. Marvig, BP 94347, 31055 Toulouse Cedex 4, France Abstract During the last few years, we have used Spark Plasma Sintering (SPS) to develop intermetallic TiAl alloys. SPS is a powder metallurgy process consisting to compact a powder by the application of direct courant pulses of high intensity under a uniaxial pressure. Its main advantage is the short processing time, allowing the minimization of physical processes as grain growth. In previous works, this technique has been used to successfully produce TiAl alloys with the so called GE composition. The product exhibit high mechanical strength and comfortable ductility at room temperature but a moderate creep resistance. Moreover, a remarkable reproducibility of these mechanical properties has been obtained. In the present study, G4 (Ti-47Al-1Re-1W-0.) and TNB (Ti-46Al-9Nb) prealloyed powders are used with the aim to improve the creep resistance since refractory elements are expected to reduce the creep rate by limiting the mobility of dislocations moving by climb. Depending on the sintering temperature and on the chemical composition, double phased and duplex microstructures were obtained. These microstructures are studied by scanning and transmission electron microscopies. The effect of the duration of the temperature plateau was also studied. The mechanical properties were measured by tensile tests at room temperature and creep experiments at 700°C. The elementary deformation mechanisms are characterized. The TNB-SPS alloy possesses a higher creep resistance than the G4-SPS alloy, whereas the latter exhibits a better ductility. The behavior and the role of the refractory elements will be compared and discussed with respect to microstructure and elementary deformation mechanisms. 2.1 The contribution of high-energy X-rays and neutrons to characterization

and development of intermetallic titanium aluminides Thomas Schmoelzer1, Klaus-Dieter Liss2, Peter Staron3, Svea Mayer1 and Helmut Clemens1

1 Department of Physical Metallurgy and Materials Testing, Montanuniversität Leoben, Franz-Josef Straße 18, 8700 Leoben, Austria.

2 Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW 2232, Australia.

3 Institute of Materials Research, Helmholtz-Zentrum Geesthacht, 21502 Geesthacht, Germany.

Abstract During the last 20 years, extensive research efforts have been undertaken to render TiAl alloys fit for service. Since this material class is intended to be used in high temperature applications, investigations under conditions that occur during service or during the

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production of parts are difficult to perform. In-situ diffraction experiments offer the opportunity to investigate various processes occurring within the material at elevated temperatures. High-energy X-rays exhibit low diffraction angles, which allows for the spacious sample environments necessary for in-situ heating and deformation experiments. Furthermore, it is possible to probe the bulk behavior of specimens rather than the surface properties due to their high penetration power. Neutrons, on the other hand, are – in the case of TiAl alloys – an ideal tool for investigating the various ordering phenomena occurring at high temperatures. Together, diffraction methods offer the opportunity to determine phase fractions accurately and gain new insights into the dynamic processes occurring during hot deformation of TiAl specimens. This presentation will highlight different techniques applicable to this material class by selected examples and discuss the opportunities and limitations imposed by each method. 2.2 In-situ observation of cracking behavior and toughening in fully lamellar

TiAl alloys INVITED PRESENTATION Masao Takeyama1, Yuji Imai1 and Toshikazu Kikugawa, Hirotoyo Nakashima

1 Tokyo Institute of Technology, S8-8, 2-12-1, Ookayama, Meguro-ku, Tokyo 152-8552, Japan Abstract Toughness is a key issue for development of wrought TiAl alloys. The wrought alloys under development using high-temperature β-Ti exhibit unique microstructures consisting of α2/γ lamellar grains and β grains, and the higher the fraction of the lamellar grains, the higher the fracture toughness. In this study, focus is placed on the lamellar grains for toughening. In-situ observation of crack initiation and propagation behavior of α2/γ and γ/γ lamellar single crystals (PST crystals) with various lamellar orientations have been conducted by means of specially designed three-point bend test in SEM chamber, using a notched rectangular specimen (2x4x30 mm3). Crack basically initiates at and propagates along the α2/γ interfaces, rather than γ/γ interfaces, regardless of the lamellar orientation. In the PST crystals with lamellar interfaces parallel to the bottom edge of the notch but inclined with respect to loading direction (angle θ), the load-displacement curves revealed elastic behavior followed by abrupt load drop, indicating that crack-opening mode (Mode I) and forward shear mode (Mode II) is responsible for the cracking behavior. On the other hand, distinct toughening occurs in the PST crystals with lamellar interfaces parallel but rotated with a certain angle (λ) with respect to the loading direction. The work hardening behavior is clearly visible, suggesting that parallel shear mode (Mode III) is responsible for the deformation. The role of α2 plate in toughening is presented. Based on this knowledge, the microstructure control for further toughening of wrought TiAl alloys will be discussed. 2.3 Effect of the beta/alpha transformation on the microstructure in gamma

TiAl alloys Michael Oehring, Andreas Stark, Jonathan Paul and Florian Pyczak

Helmholtz-Zentrum Geesthacht, Institut für Werkstoffforschung, Max-Planck-Str. 1, D-21502 Geesthacht, Germany

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Abstract Gamma titanium aluminide alloys solidifying solely via the beta-phase exhibit characteristic solidification microstructures, which often are fine and uniform and involve weak textures, as well as modest segregation. These features result from single-phase solidification and the subsequent solid-state transformations. Different alloys were subjected to heat treatments, which resulted in coarse microstructures. Subsequently the materials were heat-treated in the beta single-phase region and cooled to room temperature with different cooling rates. By applying high-energy XRD using synchrotron radiation, microstructural and EBSD analyses it was shown that the microstructural refinement can be attributed to the alloying effect on the kinetics of the beta/alpha transformation. Most strikingly dependent on alloy composition and heat treatment conditions not necessarily the fastest cooling rates produced the finest microstructures. The paper discusses different mechanisms of the beta/alpha transformation and the resulting transformation kinetics as well as alloy concepts aiming at refined cast alloys. 2.4 Effect of microstructure on hot deformability of TiAl alloys Keiji Kubushiro1, Satoshi Takahashi, Keiko Morishima1, Mikiya Arai2 and Masao Takeyama3 1 Research Laboratory, IHI Corporation, 1, Shin-Nakahara-Cho, Isogo-ku, Yokohama 235-8501 Japan 2 Research & Engieering Devision Aero-Engine & Space Operations IHI Corporation, 229 Tonogaya, Mizuho-machi, Nishitama-gun, Tokyo 190-1297, Japan 3 Dept. Metallurgy and Ceramics Science, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8552, Japan Abstract High temperature deformability using β-Ti phase of Ti-43Al-(3-9) M with various combinations of the two transition elements M (M: V, Nb, Cr, Mo) has been examined by compression to 66% reduction in height under strain rates ranging from 0.1 to 10 s-1. These alloy compositions were selected based on Ti-Al-M phase diagrams using the equivalency of M1 for M2 (M1, M2 : above trarnsition elements). The compression test specimens were prepared from the as-cast ingots. The amount of β phase (Vβ) of these alloys in as-cast state was in the range of 7.5% to 20%. All alloys show good deformability under a strain rate of 0.1 s-1, regardless of the Vβ, whereas only the alloy with Vβ=20% could successfully be compressed without cracking under a strain rate of 10 s-1. The peak stress of these alloys decreased with increasing Vβ. The detailed microstructure before and after the deformation followed by cooling will be presented. 2.5 On the quaternary phase diagram TiAl-Nb-Mo Martin Schloffer1, Emanuel Schwaighofer1, Albert Themeßl1, Helmut Clemens1, Falko Heutling2, Dietmar Helm2, Matthias Achtermann3, Svea Mayer1

1Department of Physical Metallurgy and Materials Testing, Montanuniversitaet Leoben, Roseggerstraße 12, A-8700 Leoben, Austria 2MTU Aero Engines GmbH, Dachauer Straße 665, D-80995 Munich, Germany 3GfE Metalle und Materialien GmbH, Höfener Straße 45, D-90431 Nuremberg, Germany

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Abstract Phase diagrams are fundamental to materials science in terms of adjustment and design of well-defined microstructures with optimised mechanical properties. In this study the quaternary phase diagram of the β-phase solidifying γ-TiAl-based alloy TNMTM with a nominal composition of Ti-43.5Al-4Nb-1Mo-0.1B (in at-%) is presented. The main focus is therein laid on phase transformation temperatures as well as the occurrence of the single α-phase field region as a function of chemical composition. Therefore, phase fraction diagrams at different chemical compositions within the TNM specification region were experimentally determined. The phase fractions of the annealed and water quenched samples were evaluated with complementary analytical methods. First light-optical microscope images of the particular microstructures were quantitatively analysed using the image analysis programmes Adobe Photoshop® and AnalySIS®. The obtained data were then compared with X-ray diffraction results and simultaneously transferred into quasi-binary phase diagrams along with a three-dimensional quaternary phase diagram. In order to critically evaluate the experimental results, thermodynamically calculated phase diagrams evaluated by MatCalc© and Thermo-Calc® using a commercial TiAl database were examined and the differences discussed. 2.6 Transformation kinetics in Al-rich TiAl Martin Palm1, Nico Engberding1, Frank Stein1, Stefan Irsen2 and Klemens Kelm3

1Max-Planck-Institut für Eisenforschung GmbH, Max-Planck-Str. 1, D-40237 Düsseldorf, Germany 2Research center caesar, Ludwig-Erhard-Allee 2, D-53175 Bonn, Germany 3DLR Deutsches Zentrum für Luft- und Raumfahrt e.V., Institut für Werkstoff-Forschung, Linder Höhe 51147 Köln, Germany Abstract Al-rich TiAl alloys have a better oxidation resistance and an even lower density of about 3.2 g/cm3 than TiAl + Ti3Al alloys (about 4.0 g/cm3). In order to evaluate the potential of respective alloys for alloy developments, the formation and stability of Al-rich phases in the Ti-Al system and the transformation kinetics which lead to the formation of lamellar TiAl + r-Al2Ti microstructures have been investigated. To this end several alloys with Al contents ranging from 58 to 62 at.% have been produced by levitation melting and heat treated between 800 and 1000 °C for 1, 10, 100, and 1000 h. Microstructures were observed by light-optical and scanning electron microscopy (LOM, SEM) and phases were identified by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Phase transformations were studied by differential thermal analysis (DTA) and in-situ heating experiments in the TEM and compositions of phases were determined by electron microprobe analysis (EPMA). In as-cast Al-rich TiAl the phase Al5Ti3 is present in small domains which form due to local supersaturation in Al during cooling. During prolonged annealing a tweed-like TiAl + Al5Ti3 microstructure develops. However, if the temperature is raised above a critical temperature Tcrit., Al5Ti3 dissolves and does not form again on cooling and subsequent annealing at temperatures where TiAl + Al5Ti3 microstructures were observed before, i.e. Al5Ti3 is a metastable phase. h-Al2Ti is another metastable phase that forms in Al-rich Ti-Al alloys on cooling. Two different mechanisms, a continuous and a discontinuous one, have been identified by which h-Al2Ti transforms into stable r-Al2Ti. The kinetics of these transformations have been studied in dependence on time and temperature because the discontinuous mechanism leads to lamellar TiAl + r-Al2Ti microstructures similar to the lamellar TiAl + Ti3Al microstructures to which Ti-rich TiAl alloys owe their favorable properties.

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2.7 Deformation mechanisms of PST TiAl under various strain conditions Kyosuke Kishida, Kengo Goto and Haruyuki Inui Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan Abstract TiAl/Ti3Al alloys with fully lamellar structure are of special interest because of their superior mechanical properties to those with the other microstructure types. We have been conducting systematic studies of deformation mechanisms of the lamellar microstructure using our polysynthetically twinned (PST) crystals. We have revealed that the macroscopic deformation of PST crystals is highly anisotropic in the plane perpendicular to the loading axis, when the specimens are deformed in uniaxial tension or compression. When the loading axis is parallel to the lamellar boundaries, the normal strain perpendicular to the lamellar boundaries is essentially zero, while that in the parallel direction increases. Such anisotropic macroscopic deformation was in good agreement with the anisotropy predicted on the basis of the operative deformation modes determined by TEM analysis of six orientation variants in the TiAl lamellae. In the case of polycrystalline TiAl, the anisotropic macroscopic deformation of PST crystals must be restricted by the surrounding grains. In the present study, PST crystals were deformed under plane strain condition, in which the inherent anisotropic macroscopic deformation is restricted by a channel die, so as to clarify the deformation mechanisms under constrained conditions. TEM analysis of deformation modes together with the Taylor analysis reveals that all TiAl orientation variants deform to yield the relaxed-constraint-type plastic strain, where three shear strain components are not zero for each TiAl variant but are macroscopically compensated to zero by the existence of twin-related TiAl lamellae at the early stage of deformation. The Taylor analysis assuming the relaxed constraints is found to be adaptable for predicting the operative deformation modes in TiAl at the early stage of deformation and also for correlating quantitatively the stress-strain behavior of PST crystals under prescribed strain conditions with those under the unconstrained condition. 2.8 Hardening and softening during aging of a nano-lamellar TiAl Alloy with

coherent or semi-coherent interfaces Kouichi Maruyama1, Takehiro Kamei1 and Junya Nakamura1 1Graduate School of Environmental Studies, Tohoku University, Sendai 980-8579, Japan Abstract TiAl alloys usually form a lamellar microstructure consisting of γTiAl and α2Ti3Al phases, and their mechanical properties are significantly affected by the presence of γ/α2 lamellar interfaces. There is a small lattice misfit of about 1% between the two phases, and the misfit is accommodated by elastic deformation (coherent interface on a thin γ plate) or by introducing a set of misfit dislocations onto lamellar interfaces (semi-coherent interface on a thick γ plate). The misfit dislocations also affect the mechanical properties. In the present talk it will be discussed how lamellar thickness and misfit dislocations affect mechanical properties of nano-lamellar TiAl alloy. The material used was Ti-38Al-Zr alloy containing a high fraction of γ/α2 lamellar interfaces. The alloy was solution treated in α single phase field and cooled down to room temperature. Ordered α2 single phase containing a high density of anti-site atoms remained after the cooing. The alloy was aged at several temperatures for various durations in order to form lamellar microstructures. Its yield stress increases with increasing aging time, when coherent interfaces are introduced by aging at lower temperatures. There is a critical γ thickness for

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the introduction of misfit dislocations, and thicker lamellae with semi-coherent interfaces are introduced by aging at higher temperatures. The yield stress decreases during aging in this case. The presence of misfit dislocations significantly affects yield stress of the lamellar material. Strain hardening rate after the introduction of γ/α2 interfaces is always higher than that before aging, and increases with decreasing lamellar thickness. The semi-coherent interfaces are more effective in increasing the strain hardening rate. Lamellar thickness dependence of mechanical properties of TiAl alloy is discussed on the basis of the results obtained in the present study. 2.9 Microstructure evolution during solidification and solid phase transformations

in TiAl-Based alloy Juraj Lapin1, Katarína Frkáňová2 and Zuzana Gabalcová1

1Institute of Materials and Machine Mechanics, Slovak Academy of Sciences, Račianska 75, 831 02 Bratislava 3, Slovak Republic 2Slovak University of Technology, Faculty of Materials Science and Technology, Paulínska 16, 917 24 Trnava, Slovak Republic Abstract In many TiAl-based alloys, critical cooling rates to achieve grain refinement through formation of massive γM(TiAl) are relatively high. Low cooling rates for formation of γM can be achieved by alloying with elements such as Ta and Nb, which have low diffusion coefficient in both γ(TiAl) and α2(Ti3Al) phases. Based on this concept, a new “airhardenable” Ti-46Al-8Ta (at.%) alloy requiring only air cooling to form massive γM was designed.

High temperature phase transformation sequences and phase equlibria were determined experimentally in Ti-46Al-8Ta (at.%) alloy using directional solidification technique and in-situ temperature measurements. Detailed analysis of quenched microstructures of the samples revealed that the solidification starts with the β phase (Ti-based solid solution with bcc crystal structure). The microstructural analysis of quenched mushy zone confirmed formation of α-phase (Ti-based solid solution with hcp crystal structure) by a peritectic reaction in the samples with oxygen content higher than 2000 wtppm. The solidification path was experimentally determined to be L → L + β → β → β + α and L → L + β → β + α for the Ti-46Al-8Ta (at.%) samples with oxygen content lower and higher than 2000 wtppm, respectively.

Jominy end quench test was applied to study solid phase transformations in the studied alloy. Numerical simulation of heat transfer during Jominy end quench test and cooling curves within the sample is described. Mathematical model involves the presence of vaporization, boiling and forced convection on later surface depending on surface temperature. The heat transfer from lateral and top surfaces of the Jominy sample is solved assuming combined convection and radiation conditions. Temperature field within the Jominy sample is described by heat conduction equation for isotropic material with a heat release and defined initial and boundary conditions. Thermophysical material properties required for numerical calculations such as temperature dependence of thermal diffusivity, specific heat capacity and density of the studied alloy are presented.

Before solution annealing and quenching the microstructure of the Jominy sample consisted of two types of equiaxed grains: (i) single γ (17 vol.%) and lamellar α2+γ (83 vol.%). The equiaxed γ grains were formed during HIP-ing at 1280 °C for 4 h in two phase α+γ region. Microstructure analysis revealed that the γ grains are relatively stable and can be only partially dissolved during solution annealing in a single α-phase field at 1360 °C for 1 h. Microstructure in the vicinity of the water cooled surface, at which cooling rates exceed 700 Ks-1, consists of equiaxed γ grains (about 9 vol.%) which are surrounded by massive γM (27 vol.%) and retained α-phase (64 vol.%). Maximum volume fraction of the massive γM

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of about 90 vol.% is achieved at a distance ranging from 6 to 20 mm from the water cooled surface, which corresponds to a range of cooling rates from 15 to 70 Ks-1. At these cooling rates, the equiaxed γ grains transform to α2+γ grains with convoluted type of microstructure. Volume fraction of massive γM decreases at a distance higher than 20 mm and reaches the second minimum at a distance of about 50 mm, which corresponds to a cooling rate of about 7 Ks-1. The microstructure in this region consists of massive γM (30 vol.%), equiaxed grains with convoluted α2+γ type of microstructure (8 vol.%) and lamellar α2+γ regions (62 vol.%). For the practical purposes, cooling rates ranging from 15 to 70 Ks-1 are found to be optimal for the grain refinement of the studied “airhardenable” intermetallic Ti-46Al-8Ta (at.%) alloy. 2.10 Slip transfer from gamma to alpha2 in TiAl-based alloys Michael Loretto1 and Hamish Fraser2 1 University of Birmingham, Edgbaston B15, 2TT, UK. 2 Dept. of Materials Science and Engineering, 2041 College Road, Columbus, OH, USA

Abstract Slip transfer from gamma to alpha2 plays an important part in influencing the ductility of lamellar TiAl-based alloys and observations will be reported on a number of such alloys which have been processed to produce lamellae of different widths. The influence of variables such as the orientation of the alpha2 to the stress axis and the resolved shear stress on the possible slip systems in gamma wiil be discussed. The observations show that there is a number of different ways in which deformation can be transferred ranging fron dislocation dissociation at the alpha2/gamma interface producing glissile dislocations in the alpha2 to pile-up stresses in the gamma resulting in dislocation generation from the opposite alpha2/gamma interface with no dislocation activity in the alpha2. The role of these different mechanisms of slip transfer on ductility will be discussed. 3.1 Application of γ-TiAl to automotive aftermarket turbochargers INVITED PRESENTATION David Decker

BorgWarner Turbo Systems, 1849 Brevard Road, Arden, North Carolina 28704 USA Abstract Titanium Aluminide has found application in automotive turbochargers with the obvious benefit of lower density leading to improved transient response. However, widespread use has not been achieved due to cost. Yield issues with the casting process and shaft attachment have made TiAl much more costly than the traditional Nickel alloy approach and limited application to specialty markets. The worldwide market for turbochargers is growing rapidly. TiAl could participate in this growth if cost issues can be overcome. BorgWarner has been experimenting with TiAl turbines for over a decade. Castability, fatigue strength, creep resistance and ductility have been investigated. These investigations have led to new approaches to minimize cost and novel shaft attachments. Progress has been sufficient to production release an entire family of aftermarket turbochargers in 2010. Once proven in the aftermarket, more widespread release in the OEM market is possible.

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3.2 A comparative study of cyclic Sstrain hardening and fatigue life in two PM Ti-48Al-2Cr-2Nb alloys

Marc Thomas1, Olivier Berteaux2, Roger Valle1, Monique Raffestin1, Mustapha Jouiad3 and Gilbert Hénaff4

1ONERA, 29 avenue de la Division Leclerc, 92322 Châtillon, France 2Turboméca, 64511, Bordes, France 3AMPM Center, 4700-KAUST, Thuwal 23955-6900, KSA. 4Institut P’, Département Physique et Mécanique des Matériaux, UPR 3346 CNRS ENSMA Université de Poitiers, Téléport 2, 1 avenue Clément Ader, BP 40109, 86961 Futuroscope Chasseneuil, France Abstract In this paper, cyclic strain hardening and fatigue life are examined for two Ti-48Al-2Cr-2Nb alloys prepared by powder metallurgy (PM) and supplied by Crucible Research Corp. and by GKSS, respectively. This study is part of a wider program aimed at investigating microstructural effects on the static and cyclic stress-strain behaviours at room and elevated temperatures, with the objective of tailoring a microstructure offering the best compromise between a limited cyclic strain hardening and a long fatigue life. The reference Low Cycle Fatigue (LCF) tests were conducted at a constant strain ratio (Rε=-1) with a total strain amplitude of Δεt/2=±0.4% using a triangular signal. Under such conditions, the fatigue tests revealed the importance of the powder quality in optimizing the mechanical behaviour of expectedly mature engineering materials. An analogous behaviour was found for both sources of pre-alloyed powders in terms of work hardening rate. However, significant differences observed in fatigue life, were attributed to the microstructural changes linked to the presence of defects. It is clearly stated that the microstructural optimization is guaranteed for powders with a minimum of defects and inclusions. In our previous work, heat treatment at 1340°C in the sub-transus domain leads to a duplex microstructure that was found to experience a considerably long fatigue life of about 12000 cycles together with a cumulative plastic strain of 1600% owing to the formation of a heavily developed of Vein-like structure. Therefore, complementary experiments are carried out to control the reproducibility of such fatigue results, and attempts are made to interpret the differences in properties from some microstructural variations. Our interest was also focused on the deformation mechanisms that are operative in fully-lamellar microstructures. For instance, the formation of twinning or of a Vein-like structure during initial work hardening can affect the cyclic deformation behaviour of samples for higher deformations, thus leading to modified fatigue lives. Furthermore, in order to take into account stress relaxation phenomena that can occur at high temperatures, LCF tests were compared with triangular and trapezoidal signals in order to check for any property degradation. Finally, these results will be discussed relative to the requirements for aerospace gas turbine applications. 3.3 Microstructure and mechanical properties of a forged new beta-phase

containing gamma titanium aluminide alloy Janny Lindemann1, Sebastian Bolz1, Michael Oehring2, Florian Pyczak1,2 and Dan Roth-Fagaraseanu3

1 Brandenburg University of Technology, Konrad-Wachsmann Allee 17, 03046 Cottbus, Germany 2 Institute of Materials Research, Helmholtz-Zentrum Geesthacht, Max-Planck-Str. 1, 21502 Geesthacht, Germany 3 Rolls-Royce Deutschland, Eschenweg 11, 15827 Blankenfelde-Mahlow, Germany

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Abstract Recently, the alloy design of wrought γ-TiAl alloys has focused on the development of β-phase containing alloys. These alloys solidify via the β-phase and exhibit a fine grained forgeable cast microstructure consisting of lamellar (γ+α2)-colonies and equiaxed γ and β/B2 grains. Also, the presence of β-phase, which is disordered at hot working temperature, significantly improves the hot-workability of TiAl alloys. Therefore, β-phase containing TiAl alloys are suitable for isothermal near-netshape forging of relatively large components like low pressure turbine blades for aeroengine applications. Nevertheless, the presence of β-phase in these alloys at service temperature can hamper their strength and the brittle ordered B2 variant of the β-phase can be detrimental for ductility and damage tolerance. Therefore the mechanical properties of such alloys are rather sensitive to the microstructure which is generated in a post forging heat treatment. In the present study the microstructure and mechanical properties of a nearly-isothermal forged novel beta-phase containing alloy were investigated. After forging the material was heat treated using various two step processes. The resulting microstructures were characterized by means of scanning electron microscopy and correlated with tensile and creep test results. 3.4 Materials for next generation commercial aircraft engines INVITED PRESENTATION Frank Preli1, Jörg Eßlinger2 1Pratt & Whitney, 400 Main Street MS 114-43, East Hartford, CT 06108, USA 2MTU Aero Engines GmbH, Dachauer Straße 665, 80995 München, Deutschland Abstract Next generation engine design, such as advanced versions of the Pratt & Whitney PurePower™ PW1000G engine with Geared Turbofan™ technology must balance the seemingly conflicting requirements of higher performance, reduced weight and lower cost. Instability in the price of fuel and the desire to reduce the environmental footprint of aircraft engine operation increases the need to reduce fuel burn. More efficient engines generally tax the temperature capability of materials systems and put pressure on the designers to reduce weight. State of the art turbine engines represent highly engineered complex systems. Several materials options are available to reduce the weight of the fan and compressor, such as organic matrix composites and advanced lightweight metallic materials, but cost limits their application. For the combustor and turbine, more capable nickel alloys, higher temperature capable titanium aluminide and ceramic matrix composites will be required to meet the weight and temperature requirements of future engines. Additional capability enhancements can be achieved through engineered material systems. 3.5 Assessment of fatigue sensitivity to defects of TiAl alloy produced by

electron beam melting (EBM) Mauro Filippini1, Stefano Beretta1, Luca Patriarca1, Giuseppe Pasquero2 and Silvia Sabbadini2

1Politecnico di Milano, Dipartimento di Meccanica, via La Masa 1, I-20156 Milano, Italy 2Avio S.p.A., Via I Maggio 99, I-10040 Rivalta (Torino), Italy

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Abstract Gamma titanium aluminide based alloys have become an important contender for high temperature structural applications in the aircraft industry to replace current nickel-based superalloys as the material of choice for low-pressure turbine blades. Although such materials appears very promising for the turbine engine industry, optimizing the performance improvements requires more advanced approaches to demonstrate the damage tolerance of TiAl materials with respect to intrinsic or service-generated defects. Therefore, there is a need to understand and address the specific fatigue properties of these materials to assure adequate reliability of these alloys in structural applications. The fatigue properties of a Ti-48Al-2Cr-2Nb alloy obtained by electron beam melting (EBM) with a patented process has been examined by conducting high cycle fatigue tests performed at different R ratios both at room temperature and at high temperatures, comparable to those experienced by the components during service. Additionally, a fairly large set of specimens with artificially introduced defects, has been used to conduct fatigue tests with the objective of studying the growth behavior of small cracks. Artificial defects with different sizes have been generated in the gauge section of the specimens by EDM (Electro Discharge Machining). After EDM defects were produced, the specimens have been pre-cracked in cyclic compression, so that small cracks could be generated at the root of the EDM starter defects. Fatigue tests have been conducted by applying the staircase technique with the number of cycles of censored test (runout) fixed at 107 cycles. By employing the Murakami model for the calculation of the range of stress intensity factor, the threshold stress intensity factor range dependence on the loading ratio R and on the defect size has been evaluated, highlighting the relevant parameters that govern the specific mechanisms of failure of the γ-TiAl alloy studied in the present work. 3.6 Mechanical behaviour of Ti-46Al-8Ta alloy Juraj Lapin1, Oto Bajana1, Tatiana Pelachová1

1Institute of Materials and Machine Mechanics, Slovak Academy of Sciences, Račianska 75, 831 02 Bratislava 3, Slovak Republic Abstract Coarse-grained structure of cast components leads to low room-temperature ductility, fracture toughness and large scatter of mechanical properties. In many TiAl-based alloys, the critical cooling rates to achieve massive transformations are relatively high which may results in distortion or even crack formation in complex shaped castings. In the present study, mechanical properties of cast intermetallic Ti-46Al-8Ta (at.%) alloy of the latest 4th generation requiring only free air cooling to form massive γM(TiAl) for grain refinement are presented.

During long-term ageing at 700-800 °C, the Vickers hardness and microhardness decrease with increasing ageing time reaching minimum values after the ageing for about 500 h and then increases to peak values after ageing for about 1500 h. The ageing time longer than 1500 h leads to a continuous softening of the alloy up to 10000 h.

The tensile specimens show relatively high reproducible plastic elongation to fracture close to 1% at room temperature (RT). However, when such specimens are subjected to short-term ageing at 700 °C for 2 h in air, large drop in RT ductility characterized by a decrease of plastic elongation to fracture by 82% is observed. On the other hand, removing oxygen-rich surface layer formed during ageing at 700 °C fully restores yield stress, ultimate tensile strength and RT ductility. Compression and tensile yield stress decrease with increasing temperature from RT to 850 °C.

Long-term creep tests up to 22500 h were performed at temperatures 700-800 °C and applied stresses 200-400 MPa. The measured creep deformation curves show primary creep

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stage where the creep rate decreases with increasing strain. After reaching a minimum at a strain ranging from 1.2 to 3.5 %, the creep rate increases with increasing strain. The minimum creep rate is found to depend strongly on the applied stress and temperature. The power law stress exponent of the minimum creep rate is n = 5.8 and the apparent activation energy for creep is calculated to be Qa = 382.9 kJ/mol. The kinetics of creep deformation of the specimens tested to a minimum creep rate is suggested to be controlled by dislocation climb in the γ matrix. Besides dislocation mechanisms, deformation twinning contributes significantly to overall measured strains in the specimens tested to fracture. The analysis of creep deformation curves in coordinates of true stress-true creep rate revealed significant deviation from the Norton power law. The Norton power law stress exponents determined for minimum creep rates are significantly lower than those varying from 14.4 to 21.7 determined for tertiary creep regime. These deviations can be attributed to microstructural instabilities observed in the crept specimens. During creep the initial convoluted α2(Ti3Al)+γ(TiAl) microstructure transforms to the α2+γ+τ type. The particles of the τ phase with slightly variable chemical composition of Ti-(36-40)Al-(12-15)Ta (at.%) and B82 type of crystal structure are preferentially formed along the grain and lamellar colony boundaries at the expense of the α2 lathes, which partially transform to the γ matrix and τ particles.

At lower applied stresses of 200–300 MPa, the tertiary creep stage is accompanied with nucleation and growth of cavities along the lamellar colony and grain boundaries. At higher applied stresses of 350 and 400 MPa, the tertiary creep regime is accompanied predominantly with nucleation and growth of cracks and to a lesser extent with the nucleation and growth of cavities. Majority of cracks are formed at the grain and lamellar colony boundaries inclined to load direction but some of them passed transversally the grains and lamellae perpendicularly to load direction. The analysis of the crept specimens by X-ray high-resolution computed tomography (CT) revealed 3D distribution of cavities and cracks in the gauge section. Statistical analysis of measured volume of cavities and cracks by the CT show log-normal distribution. 3.7 Isothermal low-cycle and thermo-mechanical fatigue of a high-strength

multiphase titanium aluminide alloy Ali El-Chaikh1, Thomas K. Heckel2, Hans- J. Christ1, Fritz Appel3 1Institut für Werkstofftechnik, Universität Siegen; D-57068 Siegen, Germany 2Rolls-Royce, 15827 Blankenfelde-Mahlow, Germany 3Institute for Materials Research, Helmholtz-Centre Geesthacht, D-21502 Geesthacht, Germany Abstract Most of the anticipated engineering applications of TiAl alloys involve components that are subjected to fluctuating or cyclic loading. This requires that the damage tolerance of the material with respect to intrinsic and service-generated defects be demonstrated. In this study isothermal strain-controlled low cycle fatigue (LCF) tests and thermomechanical fatigue (TMF) experiments were conducted at strain amplitudes of 0.6 und 0.7% in a temperature range from 25 to 850°C on a high-strength lamellar TiAl alloy. A very short fatigue life was found under out-of-phase TMF as compared to in-phase TMF and isothermal LCF. The life reduction can be attributed to the generation of positive mean stresses due to cyclic hardening at low temperatures and cyclic softening at high temperatures. Furthermore, out-of-phase tests in vacuum indicated a strong environmental effect of laboratory air leading to oxide scale formation at high temperature (compression) and a premature failure as a consequence of early crack formation in tension (low temperature part of TMF cycle). The investigation reveals that the TMF lives under IP and OP load are affected by the temperature range and the mean stresses (compressive σm in the case of IP-TMF, tensile σm for OP-TMF).

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3.8 Measure of Gamma Ti Aluminide for aero-engine application INVITED PRESENTATION Mikiya Arai, Shigeyuki Satou, Masafumi Kurashige IHI Corporation, Tokyo, Japan Abstract Since 1990’s, IHI has been working for implementation of Gamma Ti Aluminide alloys for aero engine application. Now Gamma alloy has become the new class of materials which contributes to the weight reduction and the improvement of fuel consumption of the engines. In design point of view, Gamma alloys have good mechanical properties for low pressure turbine blade at operating temperatures though the defect tolerances need to be considered. The cost reduction at every step of process is very important. High yield net shape casting process with good productivity, reliable high speed machining, low cost coating, and material recycling might accomplish the competitiveness against the cast Ni superalloy blade. 3.9 Development of gamma TiAl for aerospace engines Gopal Das1, Wilfried Smarsly2, F. Heutling2, U. Habel2, C. Kunze2, and D. Helm2 1Pratt & Whitney, 400 Main Street M/S 114-40, East Hartford, CT 06108, USA 2MTU Aero Engines GmbH, Dachauer Strasse 665, 80995 Munich, Germany Abstract Introduction of light-weight gamma TiAl in aero engines has been the dream of technologists for over 40 years and it is gradually becoming a reality. In this presentation we will present various activities on gamma TiAl through the years and talk about some recent work on microstructure and mechanical properties of a beta stabilized gamma TiAl called TNM alloy. 3.10 An in-situ SEM evaluation of the creep deformation behavior of a

γ-TiAl alloy R. Muñoz Moreno1,2, E. M. Ruiz Navas1, J. Llorca2, M.T. Pérez Prado2, C. J. Boehlert2,3

1 Department of Materials Science and Engineering, Universidad Carlos III de Madrid. 2 Madrid Institute for Advanced Studies of Materials (IMDEA-Materials Institute). 3 Department of Chemical Engineering and Materials Science, Michigan State University, USA. Abstract Gamma Titanium Aluminides are important intermetallics alloys targeted for high temperature aerospace applications in Low Pressure Turbines (LPT) because they can provide increased thrust-to-weight ratios and improved efficiency. LPT materials must operate in aggressive environments at temperatures up to 750ºC, and gamma titanium aluminides are projected to replace the heavier Ni-base superalloys currently being used. The intermetallics alloy studied, Ti-45Al-22XD, was extracted from a turbine blade that was processed at ITP (Madrid, Spain) via centrifugal casting in order to improve its homogeneity and avoid shrinkage. As the objective of this work was to study the deformation behavior in

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gamma TiAl alloys at service temperatures, in-situ tests were carried out in an SEM in order to observe the deformation and failure in different conditions. 700ºC tensile and tensile-creep tests were performed and SEM images were acquired during the deformation in the same area of the specimens. For the creep experiments, the tests were not paused while taking images. Interlaminar and intercolony cracking was observed during the tensile experiments and fracture occurred at a relatively low elongation-to-failure. For an in-situ creep test at a constant stress of 250MPa, classical ductile fracture occurred where cracking initiated at colony boundaries in the center of the gage section and propagated along the colony boundaries. When the cracking extended to close the edges of the sample, the cracks tended to follow a path 45 degrees to the tensile axis. From the results, it is suggested that the interlamellar regions are critical during the higher stress loading while during creep at lower stress, the colony boundaries are critical and the locations where cracking propagates. The presentation will focus on the deformation observations and microstructural features critical to the deformation evolution and ultimate fracture tension the material. 4.1 Investment cast gamma titanium aluminide low pressure turbine blades INVITED PRESENTATION Paul McQuay and Noah Third PCC Airfoils Deer Creek Operation, 4600 SE Harney Dr, Portland OR 97206 Abstract Over the last several years, Gamma TiAl alloys have finally passed over the threshold from a persistently emerging structural material, into a commercially viable one that is now in serial production for an aerospace application: Low Pressure Turbine (LPT) blades. The transition emerging to production material has required significant innovation in many process areas, significant investment, and years of hard work by numerous parties throughout the supply chain. Another important factor in this successful production transition is the development discipline known as “freeze it and use it”. In this approach materials and processes are selected and frozen under a “fixed process,” and then put into production and use. The importance of the approach is that while acknowledging that the selected alloys, processes and costs are potentially sub-optimal, they are serviceable. This release to production then allows the entire supply chain to continue to develop and refine improved processes while in production. The LPT turbine blades currently in production are cast with machine stock on all surfaces. The airfoil machining ensures parts meet dimensional and other service requirements, but at a cost higher than traditional net-shape cast nickel superalloy blades. PCC is developing investment casting processes which cast the gas-path surfaces of the blade net or near-net shape, which will reduce the amount and cost of machining. This presentation will review the technological and supply chain readiness of overstocked and net shape LPT blade casting processes, and discuss areas which require further improvement.

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4.2 High niobium containing TiAl alloy produced by electron beam melting S. Biamino1, M. Terner1, A. Penna2, U. Ackelid3, S. Sabbadini4, P. Fino1, M. Pavese1, C. Badini1

1Dipartimento di Scienza dei Materiali ed Ingegneria Chimica, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino, Italy 2AvioProp, Via Nibbia 4, S. Pietro Mosezzo, 28060 Novara, Italy 3Arcam AB, Krokslatts Fabriker 27A, SE-431 37 Molndal, Sweden 4Avio SpA, Via I Maggio 56, Rivalta, 10040 Torino, Italy Abstract In recent years additive manufacturing (AM), also variously called rapid prototyping, or solid freeform fabrication, or rapid manufacturing has emerged as a promising fabrication technology for metal parts. In particular electron beam melting (EBM), an additive manufacturing technology developed by Arcam AB in Sweden, has become an established manufacturing technology for near net-shape metal parts and already proved its suitability in order to produce Ti-48Al-2Cr-2Nb specimens to be employed in the field of aero-engines [1]. The parts are built by additive consolidation of thin layers of metal powder in a vacuum chamber which makes the process well suited for materials with a high affinity to oxygen such as titanium aluminide. At present the research about titanium aluminide is mainly focused on the increasing the oxidation resistance and retention of mechanical properties to higher temperatures by evaluating alloys containing high content of refractory elements such as Nb, Ta, Mo, etc (III generation alloys). In this work, we present the feasibility of the EBM process with Ti-46Al-2Cr-8Nb gas atomized powders used as precursor material. The microstructure, the residual porosity and the chemical composition of the samples have been investigated both immediately after EBM and after heat treatments. [1] S. Biamino. A. Penna, U. Ackelid, S. Sabbadini, O. Tassa, P. Fino, M. Pavese, P. Gennaro, C. Badini, “Electron beam melting of Ti-48Al-2Cr-2Nb alloy: microstructure and mechanical properties investigation”, Intermetallics, vol. 19/6 (2011), pp. 776-781, doi: 10.1016/j.intermet.2010.11.017 4.3 Difficulties in the up-scaling of γ-TiAl component size – a novel solution Jonathan Paul1, Uwe Lorenz1, Michael Oehring1 and Fritz Appel1

1Helmholtz-Zentrum Geesthacht, Max-Planck-Str. 1, Geesthacht, Abstract The problems associated with making large (and small) γ-TiAl components from ingot and powder material are discussed. A novel alternative technique that has been specially developed to overcome the problems described and that ensures “defect-free” material has been used to manufacture medium-sized discs from γ-TiAl using large ingots. This novel technique is outlined and the microstructural development at the various stages of processing presented.

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4.4 Oxygen removal from molten TiAl based scrap by metallothermic reduction

Bernd Friedrich, Jan Reitz, Claus Lochbichler, Jan Christoph Stoephasius, Peter Spiess, Marek Bartosinski IME Process Metallurgy and Metal Recycling, RWTH Aachen University Abstract Due to high scrap generation in the process chain of γ-TiAl products recycling shows a great potential to reduce production cost. This article presents the latest results in further developing of the IME closed loop recycling process for titanium-aluminide scrap. The combination of the industrially approved processes Vacuum Induction Melting (VIM), Pressure Electro Slag Remelting (PESR) and Vacuum Arc Remelting (VAR) with integrated metallothermic oxygen removal allow firstly the removal of bulk dissolved oxygen compared to established processes only removing surface contaminants. The primary melting of pretreated scrap (blasting, etching) is done by VIM using specialized ceramic linings and includes pre-deoxidization followed by final deoxidization in an chamber-ESR using an continuously activated reactive slag. The third processing step is VAR, in order to remove small slag inclusions as well as dissolved Ca and to allow for hydrogen degassing. The paper will show, as a significant innovation for the titanium industry, the results of semi-pilot scale experiments at IME for the production of 200 mm diameter VIM-PESR-VAR-ingots from 100 % scrap regarding process window definition and material characterization. An intensive thermochemical modeling on refractory reactions with liquid titanium and titanium alloys, on the involved deoxidization by calcium master alloys and by the active ESR slag, as well as for the removal of excess Ca and H in VAR assisted the experimental phase. The presentation will close with a general benchmark comparison with primary TiAl-production. 4.5 Solidification process of Ti45Al2Mn2NbXD David Hu1, Chao Yang1, and Ulrike Hecht2

1IRC in Materials, The University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK 2ACCESS Materials and Processing, Intzestrasse 5, 52072 Aachen, Germany Abstract The solidification process of Ti4522XD was investigated using the Bridgman–Stockbarger technique and the solidification behaviour was compared with that of boron-free Ti4522. Boron addition at about 1at% was found to have a strong effect in limiting beta dendrite growth and to have led to grain refinement during solidification. The grain refinement mechanism by boron addition is proposed. 4.6 Near conventional hot-die forging of a β-stabilized γ-TiAl based alloy

in an industrial scale Daniel Huber1, Josef Kortschak1, Helmut Clemens2 and Volker Güther3

1Böhler Schmiedetechnik GmbH & Co KG, Mariazeller Str. 25, A-8605 Kapfenberg, Austria 2Department physical metallurgy and materials testing, University of Leoben, A-8700 Leoben, Austria 3GfE Metalle und Materialien GmbH, Höfener Str. 45, D-90431 Nuremberg, Germany

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Abstract Due to the strong demand for higher efficiencies, reduced CO2 emissions and weight reduction in aircraft engines, the substitution of presently used materials by novel light-weight, high-temperature alloys like γ-TiAl based alloys has started already. Turbine blades are engine parts that are subjected to high mechanical as well as thermal loading. Thus alloys are required which provide high creep strength and fatigue properties as well as a sufficient ductility at room temperature. World-wide fundamental research conducted over the last two decades has clearly shown that balanced material properties can be obtained by hot-working and subsequent heat-treatments of TiAl alloys. Due to a small “deformation window” hot-working of TiAl alloys is a complex and difficult task and, therefore, isothermal forming processes are favored. In order to expand the process window a novel Nb and Mo containing γ-TiAl based alloy (TNMTM alloy) was developed. Due to a high volume fraction of β-phase at elevated temperatures this alloy can be hot-die forged under near conventional conditions, which entails that conventional forging equipment with minor and inexpensive modifications can be used. With subsequent heat-treatments a significant reduction of β-phase is achieved. The presentation summarizes detailed investigations on a “near conventional” forging route for the fabrication of TiAl components. 4.7 Production of γ-TiAl based feed stock materials for subsequent

investment casting and forging operations Matthias Achtermann1, Volker Güther1, Joachim Klose2 and Hans-Peter Nicolai3

1GfE Metalle und Materialien GmbH, Höfener Str. 45, D-90431 Nürnberg, Germany 2GfE Fremat GmbH, Lessingstr. 41, D-09599 Freiberg, Germany 3TiTAL GmbH, Kapellenstr. 44, D-59909 Bestwig, Germany Abstract Despite there is a very limited number of industrial suppliers worldwide, γ-TiAl ingots are commercially available on a reasonable cost basis. Unfortunately, most of applicable component manufacturing technologies such as investment casting or forging require adjusted semi-finished products as feed stock materials. Thus, ingot conversion technologies are needed which meet complex commercial and technical requirements such as:

- mass production capability - reproducibility - low alloying element deviations - defined microstructures - defined sizes / weight

A novel ingot conversion technology via VAR skull melter and centrifugal casting in permanent moulds has been developed and industrialized. This process results in semi-finished products exhibiting extremely low alloying element deviations within one production lot and a very high reproducibility between different production lots. The process is applicable to basically any γ-TiAl alloy. Compared to the conventional ingot production technologies, the materials yield has been significantly increased. A wide variety of cylindrical semi-finished parts (diameters approximately 20 mm - 100 mm, lengths up to 400 mm, weights 100 g - 15 kg) are feasible.

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4.8 Single piece flow casting development at GE Aviation Deutschland. INVITED PRESENTATION Michael Weimer1, Bernard Bewlay2, and Tobias Schubert3

1GE Aviation, 1 Neumann Way, Cincinnati OH 45215, USA 2GE Global Research, 1 Research Circle, Niskayuna, NY 12309, USA 3GE Aviation Deutschland, Junkerstrasse 10, 93055 Regensburg, Germany Abstract The GENXTM engine represents a major advancement in propulsion efficiency, realizing a 20% reduction in fuel consumption, a 50% reduction in noise and over 80% reduction in NOx emissions compared to the engines it is replacing. The GENXTM uses latest generation materials and design processes to reduce weight, improve performance and reduce maintenance costs. One of the materials advancements introduced in the GENXTM was the use of GE48-2-2 gamma TiAl LPT Blades, the world’s first certified commercial aviation application of gamma TiAl. GE TiAl LPT Blade production status along with the history and status of single piece flow casting implementation at GE Aviation Deutschland (Regensburg) will be presented. In the second half of 2006, GE began to explore near net shape casting as an alternative to the overstock conventional gravity cast plus machining approach employed to produce the ~ 30,000 TiAl LPT blades manufactured to date for GENXTM 1B (Boeing 787 series) and GENXTM 2B (Boeing 747-8) applications. For TiAl LPT Blades, single piece flow, near net shape processing has been successfully developed, achieving a 7X reduction in raw material usage compared to conventional gravity casting. GE Aviation Deutschland castings are currently undergoing final engineering evaluation and are expected to be fully certified for use on the GENXTM in 2011. 5.1 Microstructural optimization of a cast and hot-isostatically pressed

TNM™ alloy by heat treatments Emanuel Schwaighofer1, Martin Schloffer1, Thomas Schmoelzer1, Svea Mayer1, Janny Lindemann2, Volker Guether3, Joachim Klose4, and Helmut Clemens1 1 Department of Physical Metallurgy and Materials Testing, Montanuniversitaet Leoben,

Roseggerstraße 12, A-8700 Leoben, Austria 2 Chair of Physical Metallurgy and Materials Technology, Brandenburg University of

Technology, Konrad-Wachsmann-Allee 17, D-03046 Cottbus, Germany 3 GfE Metalle und Materialien GmbH, Hoefener Straße 45, D-90431 Nuremberg, Germany 4 GfE Fremat GmbH, Lessingstraße 41, D-09599 Freiberg, Germany Abstract Intermetallic γ-TiAl-based alloys are used in aircraft engines and automotive applications because of their low density and excellent high-temperature properties as compared to steels and Ni-base superalloys. Advanced γ-TiAl-based alloys are complex structured, multi-phase materials. TiAl alloys which solidify via the β-phase, such as the TNM™ alloy (Ti-43.5Al-4Nb-1Mo-0.1B, in at%) investigated in the present study, consist predominantly of γ-TiAl, α2-Ti3Al and small amounts of βo-phase, all of which are ordered at room temperature. This class of alloys shows great potential for the production of components by a casting process since it

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exhibits an almost segregation-free solidification structure with small average grain size. After casting and hot-isostatic pressing, however, a small fraction of the grains are large sized and exhibit adverse shapes. They represent internal notches which may initiate cracks under tensile loading and thereby significantly decrease the materials ductility at room temperature. In this study, the potential of special heat treatments to refine coarse grains and thus to homogenize the microstructure is assessed. A final heat treatment step targets to adjust balanced mechanical properties, i.e. high creep strength as well as sufficient ductility at room temperature. The heat-treated samples were characterized by means of light optical and scanning electron microscopy. Tensile tests and creep tests were performed to relate the microstructural features to mechanical properties. The results of these experiments are presented and the impact on the establishment of a novel, cost-effective and time-efficient production route is discussed. 5.2 Supercast Titanium -TiAl - material for the automotive and aerospace

sector and its processing Hans Billhofer Linn High Therm GmbH, Heinrich-Hertz-Platz 1, D-92275 Eschenfelden Abstract Due to the outstanding physical and chemical properties of titanium and titanium alloys including biocompatibility, such materials are being more and more needed in automotive, aerospace and biomedical applications. Because of the low density of intermetallic TiAl if compare to Ti alloys, TiAl is a favourable material for plenty of applications in aircrafts and combustion engines (such as turbine blades, turbochargers, pistons and valves). Additionally, TiAl is used in the optical industry and medical technology as well. The use of TiAl – turbine blades and turbochargers results in the reduction of oscillating masses and, thus, in a reduction of the specific fuel consumption of turbines and combustion engines. 5.3 Vacuum furnace concepts for titanium aluminides Pavel Seserko, Ulrich Betz, Thomas Ruppel and Björn Sehring ALD Vacuum Technologies GmbH, Wilhelm-Rohnstr.35, D-63450 Hanau, Germany Abstract The Melting and pouring of γ-TiAl is easy in principal if you use the right type of equipment with all necessary features and performance. Not only do the end product require a specific solution for the casting method but also the materials specification and targeted properties of the casting, need to be met. Various vacuum furnace concepts, using different melting and pouring geometries, single part and multiple part production management, using gravity or centrifugal forces to fill the moulds are discussed in this paper with regard to their strengths and their specific limitations. It will be shown that a single universal furnace which can optimally be used for the various type of products does not exist yet.

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5.4 Selective laser melting of titanium aluminides Lukas Löber1, Holger Schwab1,2, Denis Klemm1, Uta Kühn1 Jürgen Eckert1,2 1 IFW Dresden, Helmholzstraße 20, 01069 Dresden, Germany 2 Technische Universität Dresden, 01062 Dresden, Germany Abstract Titanium Aluminides (TiAl) alloys exhibit a wide range of interesting properties which makes them a good candidate for exchanging heavy weigh Nickel-based super alloys in jet turbine engines. The poor mechanical properties at room temperature make them difficult to process. Selective Laser Melting (SLM) is used for the first time to produce simple geometries from a gamma titanium aluminide alloy: Ti-48Al-2Cr-2Nb. The layer wise principle of this additive manufacturing technique leads to the possibility of unlimited freedom in terms of complexity in parts. The part is directly created form powder thus avoiding the difficult processes to produce conventional TiAl parts. A detailed study and a design of experiments (DOE) are conducted to find optimal process parameters related to the density of the parts. Three different types to determine the density are carried out to reduce the possible errors in the measurements. In addition a complete microstructural characterization is held. 5.5 Interference-fit Joint of TiAl Rotor to Steel Shaft Ji Zhang China Iron and Steel Research Institute Group, Beijing 100081, P.R. China Abstract Connecting TiAl turbochargers to the steel shaft is an essential procedure to apply this light–weight material in diesel engines. The presented method includes firstly interference-fit joint between TiAl turbochargers and Ni-based superalloys, and then friction welding the superalloy heads to the steel shaft. The last technology has relatively grown mature. So, the success of suggested technology depends mostly on the interference-fit joint process. In principle, interference-fit Joint is a simple configuration and produces connection strength with good credibility. However, the preliminary experiments showed that the strength is rather undulatory under same interference magnitude. It is believed to be derived from the conflicting effect of the magnitude of interference that should be large enough to transmit movements but under a limit to assure the strength of the joined elements, especially TiAl. In order to improve the reliability of joints, this work analyzes the stress concentration and maximum contact stress generated by interference-fit assembling and their detrimental effect on the TiAl parts. Accordingly, increasing transitional arc radius or adding stress relieving slot are considered to avoid the material damage. The tensile and the endurance tests have proved that the proposed interference-fit joint design with stress relieving slots can produce the repeatable connection strength and at mean time generate the contact stress within the materials’ tolerance. 5.6 Friction welding and laser beam welding of TNM-based TiAl joints

with regeneration of microstructure by heat treatment Heidi Cramer, Ludwig Appel and Peter Limley GSI mbH, NL SLV München, Schachenmeierstr. 37, D-80636 München, Germany

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Abstract For further applications parts or structures of TiAl can not only be produced as a monolite part by casting, extrusion, forging and mechanical processing. Weldability of TiAl with conventional methods of pressure welding or fusion welding is an important material-attribute for efficient production, by joining parts of different geometry or material type. Friction welding and Laser Beam Welding are known as established welding processes, but may be complicated to be used on TiAl because of local mechanical and thermical stress. TNM-based TiAl with increased ductility offers improved conditions for weldability. On Ti-43,5Al-4Nb-1Mo-0,1B, in casted and extruded basic status, the practicability of friction welding and laser beam welding with or without 2-step-post-weld-heat-treatment has been developed. Weldability and processing-conditions of tri-phasic (γ, α, β) TiAl have been improved compared to conventional bi-phasic (γ, α) TiAl. Friction welds and Laser beam welds in as-welded-condition feature non homogeneous micro structure and various mechanical properties over the welding zone. By additional post-weld-heat-treatment the microstructure can be regenerated and homogenized over the welding zone. Mechanical properties may achieve near those of the base materials. 6.1 A "coating by design" approach applied to the optimization of an Au

coated Ti-48Al-2Cr-2Nb alloy Jean-Francois Caudrelier, Marie-Pierre Bacos and Marc Thomas

ONERA, 29 av. du General Leclerc, FR-92320 Chatillon, France Abstract A 25µm-thick Au plating is an effective process to protect a Ti-48Al-2Cr-2Nb alloy against oxidation and NaCl salt-corrosion, at 800°C and 600°C respectively. The Au-diffused zone is composed, from the surface to the bulk alloy, of two successive coatings (TiAlAu2 and TiAlAu) and of a TiAl zone enriched in Au. The upper TiAlAu2 layer transformed, during oxidation and NaCl salt corrosion, into a brittle TiAu2 layer topped by a protective alumina scale. However, the creep life of Au-coated TiAl at 700°C and a 300 MPa load is slightly lower than the one of uncoated samples. By applying an original "coating by design" approach, based on experimental and numerical analysis, the goal of the study is to specify the best layer arrangement of the Au-diffused zone, giving the most effective mechanical and chemical strength to Au-coated TiAl samples. In parallel, understanding of diffusion phenomena will permit to elaborate it. First results of this approach will be presented. 6.2 Recent Advances in the Understanding of the Halogen Effect for

Oxidation Protection of TiAl INVITED PRESENTATION Michael Schütze, Alexander Donchev and Simone Friedle

DECHEMA e.V. Karl-Winnacker-Institut, Theodor-Heuss-Allee 25, D-60486 Frankfurt am Main/Germany Abstract Small amounts of halogens (such as F, Cl, Br, I) improve the high temperature oxidation resistance of TiAl-alloys by several orders of magnitude. This so-called halogen effect occurs due to a change in the oxidation mechanism. A protective alumina layer is formed during

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high temperature exposure in oxidizing environments instead of a fast growing mixed oxide scale which is found on untreated specimens. It was established that fluorine is the best doping element, affording very thin adherent alumina layers over long time periods at temperatures up to 1050°C under thermocyclic conditions and in different atmospheres (H2O, SO2,…). Fluorine-rich regions are generally found underneath this thin alumina layer. A TEM analysis revealed that this fluorine consists solely of solid AlF3 and no titanium fluorides are present. Several fluorine application methods have been established which include simple liquid phase treatments like spraying or dipping as well as gas phase treatments and more sophisticated physical methods like ion implantation. These methods have also been successfully applied for the oxidation protection of industrial components, such as turbo charger rotors for automotive engines or turbine blades for aero-engines. The paper addresses the most recent advances in the research of the halogen effect.

6.3 Oxidation protection of TiAl alloys by plasma-based ion implantation of

fluorine Rossen Yankov1, Andreas Kolitsch1, Johannes von Borany1, Arndt Mücklich1, Frans Munnik1, Alexander Donchev2 and Michael Schütze2

1Institute of Ion Beam Physics and Materials Research, Helmholtz_Zentrum Dresden-Rossendorf, POB 510119, 01314 Dresden, Germany 2Karl-Winnacker-Institut, DECHEMA e.V., Theodor-Heuss-Allee 25, 60486 Frankfurt am Main, Germany Abstract Plasma-based ion implantation (PBII) of fluorine is a promising technique for enhancing the high-temperature oxidation resistance of γ-TiAl alloys. This talk is in two parts. The first part summarizes our recent progress in utilizing the PBII process. Experimental results are presented that give an insight into the behavior of the ion-implanted fluorine and its role in the formation of a protective alumina scale under conditions of both isothermal and thermal cyclic oxidation at temperatures in the range of 720° to 1050°C. Although PBII of F is not yet a commercially feasible proposition, shown are examples that give a flavor of potential

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applications (turbine blades and turbochargers). The second part of the talk deals with enhancing the environmental durability of Ti and some low-Al content (typically < 10 at.%) Ti-base alloys at elevated temperatures by forming a protective coating on the alloy surface. The coating is accomplished through a three-step process, namely co-deposition of Ti and Al by magnetron sputtering onto a substrate material followed by vacuum annealing to form a layer of γ-TiAl, which is finally treated by PIII of F to provide the necessary conditions for triggering the halogen effect. Shown are analysis data detailing the microstructure and the phase formation in the coating material. 6.4 Characterisation of oxidation protective coatings for titanium aluminides Laurent Bortolotto1, Cecile Langlade2, Bernadeta Pelic3, David Rafaja3, Michael Schütze1, Hans Jürgen Seifert 3, Gerhard Wolf 4 and Patrick J. Masset5

1DECHEMA e.V., Karl-Winnacker-Institut, Theodor-Heuss-Allee 25, D-60486 Frankfurt/Main, Germany

2Technical University of Belfort-Montbeliard (UTBM), LERMPS/IMAP, F-90010 Belfort, France 3Freiberg University of Mining and Technology, Institute of Materials Science, Gustav-Zeuner-Str. 5, D-09599 Freiberg, Germany 4ATZ Entwicklungszentrum, An der Maxhütte 1, D-92237 Sulzbach-Rosenberg, Germany 5Freiberg University of Mining and Technology, Centre for Innovation Competence Virtuhcon, Fuchsmühlenweg 9, D-09596 Freiberg, Germany Abstract With half the density yet equivalent mechanical properties at elevated temperatures compared to Ni-based super alloys, titanium aluminides are a promising class of materials that have the potential to progressively replace super alloys in applications where mass is a critical parameter, i.e. in rotating parts of aeronautical and automobile components. As a main drawback, they suffer environmental embrittlement caused by hot gases at temperatures above 700°C, which drastically deteriorates their mechanical properties and thus restricts their application window to this temperature. In this work, Al-rich coatings including ductilising elements such as Cr were developed using CVD, PVD and HVOF techniques and applied to titanium aluminides as an oxidation barrier. Their influence on the substrate properties after oxidation in combination and comparison to the halogen effect (fluorine surface treatment) was characterised by means of analytical techniques (EPMA, glancing XRD). Mechanical investigations (impact testing, 4 point bending with acoustic emission) aimed at evaluating and comparing the resistance of as received and coated alloys after high temperature exposure. The oxidation behaviour of coated specimens in air was evaluated in the range of target temperatures for industrial applications (up to 900°C), whereas salt corrosion tests were conducted using Na2SO4-NaCl mixtures in dry and wet environments at similar temperatures. It was shown that some of the developed coatings reduce the embrittlement sensitivity of these alloys. The present paper will focus on the description of the structure and features of titanium aluminide samples coated with different types of advanced layers and exposed to severe environments. The benefits of the coatings will be discussed. 6.5 ACETAL: recent progress on the development of advanced coatings for titanium aluminides Patrick J. Masset Freiberg University of Mining and Technology, Centre for Innovation Competence Virtuhcon, Fuchsmühlenweg 9, D-09596 Freiberg, Germany

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Abstract Titanium aluminides are promising materials for aeronautic and automobile applications as they exhibit good mechanical properties even at high temperatures, and this, for a specific density which is half of classical nickel based super alloys. Their implementation would allow a significant reduction of mechanical strains on rotating pieces and consequent decrease of the fuel consumption, which would lead to positive environmental effects. However, titanium aluminides embrittle rapidly if they are in contact with hot gases. This embrittlement deteriorates drastically their mechanical properties and excludes their industrial applications at the temperatures above 500 °C. Therefore, the development of coatings or surface modifications intended to create a stable physical barrier to hot gases is necessary. ACETAL is the acronym for Advanced Coatings to suppress environmental Embrittlement of TiAl Alloys. This interdisciplinary project (CORNET program) is running at 7 institutions in Germany (Dechema, TU Freiberg, HZG, ATZ, and HZDR) and in Austria (ÖGI, TU Vienna) and involving 10 small companies (SMEs) in both countries as well as large companies (GfE, Plansee, Linde Gas, Sulzer-Metco, Rolls-Royce) that produce the TiAl alloys up to End-Users This presentation will provide an overview of the results obtained so far, starting with the alloy properties up to the mechanical properties of coated specimens to reduce the environmental embrittlement of selected alloys (GE, TNB).The presentation will be focused on the key parameters, which influence the surface engineering of this class of materials in relation with the development of new coatings. An overview of the coatings obtained by chemical and physical techniques (MO-CVD, CVD, PVD and HVOF) will be given. The effect of the halogen implantation on their oxidation and corrosion behaviors will be discussed in more detail. Finally, mechanical tests (tensile, 4 BP, fatigue) carried out on the best coated samples suitable to reduce environmental embrittlement will be discussed.

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4th International Workshop on Titanium Aluminides – Poster Session P1 Axial-torsional thermo-mechanical fatigue of a near-gamma TiAl-alloy S. Brookes1*, H.-J. Kühn1, B. Skrotzki1, R. Sievert1, H. Klingelhöffer1

1BAM Federal Institute for Materials Research and Testing, Unter den Eichen 87, D-12205 Berlin, Germany *Now at: Rolls-Royce Mechanical Test Operations Centre GmbH, D-15827 Blankenfelde-Mahlow, Germany Abstract Structural components in aeronautical gas turbine engines typically experience large variations in temperatures and multiaxial states of stress under non-isothermal conditions. A future candidate to replace current superalloys is considered to be alloys of near-gamma Titanium Aluminides in particular those that contain a relatively high amount of Niobium. In our work, for the first time, we studied the effect of uniaxial, torsional and biaxial thermo-mechanical fatigue on a γ-TiAl alloy (Ti-45Al-5Nb-0.2B-0.2C) with duplex microstructure. The uniaxial, torsional and biaxial thermo-mechanical fatigue behavior of a γ-TiAl alloy have been examined between 400 and 800 °C and with strain amplitudes from 0.15 % to 0.7 %. The tests were conducted at both in-phase and out-of-phase. For the same lifetimes, uniaxial IP tests required the highest strain amplitudes, while OP test conditions were most damaging and needed the lowest strain amplitudes. The Mises equivalent mechanical strain amplitudes of pure torsional tests were found in between uniaxial in-phase and out-of-phase tests for the same lifetimes. The non-proportional multiaxial out-of-phase test showed a lower lifetime at the same equivalent mechanical strain amplitude compared to the other types of tests. The results obtained for the TiAl-alloy were compared to uniaxial TMF-tests on nickel base alloys IN 738 and Nimonic 90. P2 Protective Coatings for TiAl-alloys - Powder Production and Thermal

Spraying Florian Pyczak1, Jonathan Paul1, Frank Peter Schimansky1, Gerhard Wolf2, Nicole Mehrl2 and Martin Faulstich2

1Helmholtz-Zentrum Geesthacht, Max-Planck-Str. 1, D-21512 Geesthacht, Germany 2ATZ Entwicklungszentrum, An der Maxhütte 1, D-92237 Sulzbach-Rosenberg, Germany Abstract The service temperature up to which unprotected γ-TiAl alloys can be employed is restricted to about 700 °C due to oxidation. Thus coating systems for protection against oxidation are an interesting issue for this material. In addition γ-TiAl alloys suffer from a so called environmental embrittlement. If the material is exposed to high temperatures, even under reduced oxygen pressure, the low temperature ductility, which is already rather limited in γ-TiAl alloys, is lost. Unfortunately, protection measures against oxidation do not necessarily also avoid environmental embrittlement. To address these problems, coating systems based on the single γ-phase have been tested. These coating alloys are produced as alloy powder using electrode induction melting gas atomization (EIGA) technique. Despite of the fact that these single phase coating alloys are more brittle compared to common two phase TiAl alloys, powder production is nevertheless possible. Due to the pick-up of minor elements the aluminum content has to be increased further than expected from the binary Ti-Al phase

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diagram to ensure that only single γ-phase is present in the alloys. The coating process itself has been performed by thermal spraying (APS and HVOF techniques). Dense coatings with porosities << 1% were achieved using powder particle sizes up to 90 µm. It is shown that, in comparison to an uncoated Ti-48Al-2Cr-2Nb alloy, an aluminum content of 54 at-% already leads to a remarkably lower oxidation rate when exposed to air at 900 °C for over 500 h. P3 Linking microstructural and mechanical properties on different length

scales for near γ-TiAl alloys Klemens Kelm1, Mohammad Rizviul Kabir1, Liudmila Chernova1, Marion Bartsch1 and Nikolay Zotov2 1German Aerospace Center, Linder Höhe, D-51147 Köln, Germany 2Reserch Center Jülich, IEF 1, D-52425 Jülich, Germany Abstract TiAl-alloys exhibit complex microstructures, which involve in so called “lamellar” or “duplex” alloys as characteristic feature grain like lamellar colonies with lamellae consisting of α2-Ti3Al and γ-TiAl and, depending on composition, processing route, and thermal treatment possibly additional grain structures and phases. Mechanical properties are controlled by these microstructural features. However, it is sometimes difficult to link specific microstructures on micro- and nanometer level with macroscopic mechanical properties based on material physics knowledge. In this contribution we show for distinctive microstructures of a near γ-TiAl alloy how experimental methods on the nano- and micro scale are used to predict macroscopic mechanical properties by means of numerical modeling and simulation. Material for all investigations was taken from one single rod processed by arc melting, extruding, and forging. The nominal chemical composition of the material is Ti-45AL-5Nb-0.5B (at %). Eight samples used for further thermal treatment and mechanical tests on different length scales were cut from locations in the center of the rod, where the degree of deformation after forging is almost identical. The samples were annealed in argon at temperatures from 1230° up to 1300°C, each sample at a maximum temperature higher by 10°C. The thermal treatment resulted in distinctive microstructures with increasing size of lamellar colonies and decreasing thickness of the lamellae with increasing annealing temperature. The microstructures of the samples were characterized by means of scanning electron microscopy for quantitative data on colony and grain size of the different phases. Lamellae phase composition and thicknesses were determined by scanning transmission electron microscopy (STEM) in combination with high angle annular dark field (HAADF). This methodology allows – compared to conventional TEM - for fast analysis of large areas using automatic data extraction. Furthermore, the requirements for orientation adjustment and sample thickness are less strict. The microstructural information was used as geometric input for creating a fully linked 2 – scale numerical FEM model with periodic unit cells on the micro level, describing the lamellae geometry and orientation and a mesoscopic model, comprising the information on colony and grain size, orientation, and spatial distribution. The material properties of the different phases were taken as crystal plasticity data from literature data of single crystals or polysynthetically twinned (PST) crystals, respectively. From each sample three tensile test specimens were machined and tested at ambient temperature. On the same samples nanoindentation tests were performed, providing local

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material properties on the scale of single grains and colonies. Both types of experiments – nanoindentation on micrometer level and tensile tests on millimeter level - were modeled and simulated for distinctive microstructures. The results of numerical calculations and mechanical experiments were consistent, demonstrating the successful linking of microstructural information on nano- and micrometer level with mechanical properties on micro- and millimeter level. P4 Thermodynamic assessment of the Ti-Al-Nb, Ti-Al-Cr, and Ti-Al-Mo

systems Mario Kriegel1, Damian M. Cupid2, Olga Fabrichnaya1, Hans J. Seifert2

1Technische Universität Bergakdemie Freiberg, Institut für Werkstoffwissenschaft, Gustav-Zeuner-Strasse 5, 09599, Freiberg, Germany 2Karlsruher Institut für Technologie (KIT), Institut für Angewandte Materialien - Angewandte Werkstoffphysik (IAM-AWP), Hermann-von-Helmholtz-Platz 1, Gebäude 681, 76344, Eggenstein-Leopoldshafen, Germany Abstract Two-phase alloys based on a microstructure of disconnected sigma Nb2Al precipitates within a gamma TiAl matrix are promising materials for gas turbine blades because of their expected creep resistance and fracture toughness properties. To optimize alloy microstructures, the respective alloys should solidify as single phase beta, and, on aging transform to the two phase microstructures. To extend the high temperature single phase beta field to optimal compositions, beta stabilizers such as Cr and Mo may be used. The CALculation of PHAse Diagrams (CALPHAD) method is a powerful tool that can be used to guide materials design through the application of computational thermodynamics to the calculation of phase diagrams in multi-component systems. Existing thermodynamic descriptions for the Ti-Al-Nb, Ti-Al-Cr and Ti-Al-Mo systems, however, could not reproduce recent experimentally determined phase equilibria. Therefore, CALPHAD based re-optimizations of the thermodynamic parameters of the phases in the multi-component system descriptions were performed. The re-optimized description for the Ti-Al-Nb system calculates the experimentally observed extension of the primary crystallization field of the beta phase, the existence of the single phase beta field at sub-solidus temperatures, and the solid state phase transformations and phase transformation temperatures of two experimentally investigated alloys. Calculations using the new description of the Ti-Al-Cr system are able to reproduce the ternary extension of the Laves phases based on TiCr2, the critically evaluated liquidus surface, and isothermal sections at 1073 K and 1273 K. The continuity of the ternary beta phase in the Ti-Al-Mo system to the Al-Mo binary could only be reproduced through re-optimization of the thermodynamic parameters for the Al-Mo binary sub-system. The new Al-Mo binary description calculates the congruent melting of the beta phase at 50 atomic % Al, and the new Ti-Al-Mo description is in excellent agreement with the extension of the single phase beta field to the Al-Mo binary and the invariant reaction between the beta, delta, Al8Mo3, and eta phases at 1540 K.

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P5 Thermomechanical fatigue behavior of the γ-TiAl based alloy TNB-V5 Markus Hoffmann1, Marcel Roth1, 2 and Horst Biermann1

1Institut für Werkstofftechnik, TU Bergakademie Freiberg, Gustav-Zeuner-Str. 5, D-09599 1Freiberg, Germany 2now at IAV GmbH, Kauffahrtei 25, 09120 Chemnitz, Germany Abstract The cyclic deformation behavior of the γ-TiAl based alloy TNB-V5 was investigated under isothermal and thermo-mechanical conditions for three microstructures (near-gamma, duplex, fully-lamellar). The temperature-strain cycles of the thermo-mechanical fatigue (TMF) tests were carried out at different temperature ranges from 400°C to 800°C and different phase relationships (In-Phase, Out-of-Phase, Clockwise-Diamond and Counter-Clockwise-Diamond). The influence of the phase relationships between strain and temperature on the cyclic deformation curves, stress-strain hysteresis loops and fatigue lives are discussed. Under all test conditions, the near-gamma and the duplex microstructures show nearly the same fatigue lives. Due to the large mean stresses during the TMF tests, the damage parameter PSWT, suggested by Smith, Watson and Topper, is suitable for fatigue live prediction. In the PSWT parameter the maximum tensile stress, the mechanical strain amplitude and the Young’s modulus are considered. The good applicability of this parameter is given at maximum temperatures above the ductile-to-brittle transition temperature at 700°C. For temperature ranges with a maximum temperature below 700°C the quality of the lifetime prediction is not acceptable, because of the completely brittle material behavior. To improve the high-temperature oxidation behavior of the γ-TiAl based alloys a NiCoCrAlY coating was deposited by high velocity oxy-fuel flame spray (HVOF). First results on the coating quality and its influence on the isothermal and thermo-mechanical fatigue life are presented and discussed. P6 Solidification behaviour of TiAl-based alloys Zuzana Gabalcová1, Juraj Lapin1

1Institute of Materials and Machine Mechanics, Slovak Academy of Sciences, Račianska 75, 831 02 Bratislava 3, Slovak Republic Abstract The effect of solidifications parameters such as the growth rate V and temperature gradient in liquid at solid-liquid interface GL on primary and secondary dendrite arm spacings and columnar to equiaxed transition (CET) during directional solidification at steady and non-steady state conditions were studied in Ti-46Al-8Nb (at.%) and Ti-46Al-8Ta (at.%) alloys. The directional solidification was conducted under argon atmosphere in a Bridgman type apparatus using cylindrical moulds made of high-purity Y2O3. Columnar dendritic growth was studied at steady-state growth conditions using constant growth rates V ranging from 5.56x10-6 to 1.18x10-4 ms-1 and constant temperature gradients GL ranging from 0.8x103 to 8x103 Km-1. CET was studied at two different non-steady state growth conditions: (i) growth at a constant GL and continuous increase of an initial growth rate V1 to a final rate V2 and (ii) growth at a constant growth rate V and continuous decrease of an initial temperature gradient GL1 to a final gradient GL2. During directional solidification, the primary solidification phase is identified to be β phase with bcc crystal structure. Microstructural analysis of the mushy zones of Ti-46Al-8Nb (at.%) samples with oxygen content up to 2500 wtppm excluded a peritectic reaction during near equilibrium directional solidification. According to experimental study, the solidification path is determined to be L → L + β → β → β + α. Detailed analysis of quenched microstructures of

Page 38 / 52


Ti-46Al-8Ta (at.%) samples with oxygen content lower than 2000 wtppm revealed that the solidification starts with the β phase. The microstructural analysis of quenched mushy zone confirmed formation of α phase (Ti based solid solution with hcp crystal structure) by a peritectic reaction in the samples with oxygen content higher than 2000 wtppm. The solidification path was experimentally determined to be L→ L + β → β → β + α and L → L + β → β + α for the Ti-46Al-8Ta (at.%) samples with oxygen content lower and higher than 2000 wtppm, respectively. Primary dendrite arm spacing (PDAS) λ1 and secondary dendrite arm spacing (SDAS) λ2 increase with decreasing V and GL according to relationship 1

a -bLV Gλ −∝ and ( )2λ ∝

nLVG ,

respectively. The variation of PDAS with V and GL is in a good agreement with the theoretical models as well as with the experimental results reported for a TiAl-based alloy with α primary solidification phase. The CET diagram was determined experimentally for the studied alloy and compared with available data of other alloys. Critical values of solidification parameter (GL/V)crit for achieving CET in Ti-46Al-8Nb (at.%) alloy were calculated from critical values of local growth rates and local temperature gradients. Critical parameter (GL/V)crit for the growth of columnar grains is determined experimentally to be (GL/V)crit = (6.92 ± 0.31)x106 Ksm-2. Directional solidification at (GL/V) < (6.92 ± 0.31)x106 Ksm-2 leads to the growth of equiaxed grains. Directional solidification experiments of Ti-46Al-8Ta (at.%) alloy at non-steady state growth conditions showed formation of retained α, massive γM(TiAl) and feathery γ phases within the samples at all applied growth conditions. These solid state transformations avoided to determine an exact position and calculate critical local growth parameters of CET after directional solidification. P7 Beam welding and brazing of γ-titanium aluminide for linear and

circumferential joints Uwe Reisgen1, Simon Olschok1, Alexander Backhaus1

1ISF - Welding and Joining Institute, RWTH Aachen University, Pontstrasse 49, 52062 Aachen, Germany Abstract From the economic and also from the production point of view, the development of suitable joining techniques is a decisive factor for the industrial application of γ-titanium aluminide. The excellent properties of titanium aluminide with high niobium content of 5 - 8%, such as high specific strength, high temperature loads, creep resistance and also the resistance to oxidation shall be maintained in the joining point. Materials’ high brittleness and thus susceptibility to cracking are a challenge for welding with high cooling rates. The melting in the fusion zone is changing the material properties by segregation and diffusion. In order to avoid those problems, the process control is very important in joining. It is, for example, possible to approximate the microstructure in the joining zone to that of the base material via the application of a suitable, process-integrated beam deflection or via post- or pre-heating. In this publication, suitable joining strategies for the welding of modern γ-titanium aluminides (TNB V5) via electron or laser beam are presented. Different brazing materials are used for the beam-brazing of heat-treatable steels and ni-based alloys to titanium aluminides.

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P8 Environmental protection capability of different coating systems deposited on gamma titanium aluminides

Reinhold Braun1, Christoph Leyens1,2, Papken Eh. Hovsepian3, Arutiun P. Ehiasarian3, Maik Fröhlich4 1DLR – German Aerospace Center, Institute of Materials Research, D-51170 Köln, Germany 2Technische Universität Dresden, Institute of Materials Science, D-01062 Dresden, Germany 3Nanotechnology Centre for PVD Research, Sheffield Hallam University, Sheffield S1 1WB, United Kingdom 4University of Kiel, Institute of Experimental and Applied Physics, D-24098 Kiel, Germany Abstract Intermetallic alloys based on γ-TiAl are promising candidates for high temperature applications in automotive and aero engines. However, their oxidation resistance is insufficient at temperatures above 800°C. To increase the service temperature the use of protective coatings is a suitable method to improve the oxidation resistance of γ-TiAl components. Metallic and ceramic overlay coatings have been investigated. Thermal barrier coatings (TBCs), widely applied in aero-engines and land-based gas turbines, enable to reduce the surface temperature of components with internal cooling and can be used to enhance the durability of the component or to increase the gas temperature. The aims of this work were to study the oxidation protection capability of intermetallic Ti-Al based coatings and nitride thin films was well as the performance of TBC systems on γ-TiAl alloys using these oxidation resistant coatings as bond coats. The oxidation protective coatings were produced by unbalanced magnetron sputtering and high power impulse magnetron sputtering techniques. On pre-oxidised coated γ-TiAl samples, thermal barrier coatings of 7wt% yttria partially stabilized zirconia were deposited using electron-beam physical vapour deposition. The oxidation behaviour of the coated γ-TiAl alloy and the lifetime of the TBC systems were determined in the temperature range between 850 and 1000°C performing cyclic oxidation tests of 1h dwell time at high temperature in laboratory air. CrAlYN/CrN nanoscale multilayer coatings exhibited a slow oxidation rate at 850°C, providing effective oxidation protection to γ-TiAl for exposure time periods exceeding 2500 1-h cycles. The nitride films with an oxy-nitride overcoat also showed high oxidation resistance at 900°C. Intermetallic Ti-Al-Cr layers possessed high oxidation resistance at 900°C for up to 1000 1-h cycles. Their slow oxide growth rate was associated with the formation of a continuous alumina top scale established by the Ti(Cr,Al)2 Laves phase and the Z-phase (Ti5Al3O2). Small additions of Hf and Y enhanced the oxidation protection capacity of these coatings. Ti-Al-Cr-Y coatings demonstrated very good oxidation behaviour at 950°C, but degraded during prolonged exposure at 1000°C. Intermetallic Ti-Al-Cr-Zr layers produced by high power impulse magnetron sputtering exhibited excellent oxidation resistance at 1000°C. After 1000 1-h cycles of exposure, a protective alumina scale was still present on top of the coating. The concept of thermal barrier coatings was successfully applied on titanium aluminides. Lifetimes exceeding 1000 1-h cycles at 900°C were determined for the TBC system with CrAlYN/CrN bond coat. The TBC system consisting of Ti-Al-Cr-Y bond coat and YSZ topcoat survived 1000 1-h cycles at 950°C. The EB-PVD thermal barrier coating was well adherent to the alumina scale formed on the intermetallic layer. The latter TBC system failed when thermally cycled at 1000°C. Failure was associated with spallation of the thermally grown oxide scale. Thus, the lifetime of TBC systems on titanium aluminides significantly depends on the oxidation protection capacity of the bond coats used.

Page 40 / 52


List of attending organizations

□ Access e.V., Germany □ AGH University of Science and Technology, Poland □ AKRAPOVIČ d.d., Slovenia □ Alcoa Power & Propulsion, Howmet SAS □ ALD Vacuum Technologies GmbH, Germany □ All-Russian Institute of Aviation Materials, Russian Federation □ Arcam AB, Sweden □ ATI Wah Chang, USA □ AUDI AG, Germany □ Aviatech, Russian Federation □ Avio SpA, Italy □ AVIOPROP S.r.l., Italy □ BAM Bundesanstalt für Materialforschung und –prüfung, Germany □ Böhler Schmiedetechnik GmbH & Co KG, Austria □ Borg Warner Engineering GmbH, Germany □ Borg Warner Turbo Systems, United Kingdom □ Borg Warner Turbo Systems GmbH, Germany □ BorgWarner Turbo Systems, USA □ Brandenburg University of Technology, Germany □ Carleton University Mechanical and Aerospace Engineering, Canada □ CEMES-CNRS, France □ CENTRO SVILUPPO MATERIALI SPA, Italy □ Ceramic & Metallurgy Technologies, GE Global Research, USA □ China Iron and Steel Research Institute Group, China □ Continental Automotive GmbH, Germany □ Daido Castings Corp., Ltd., Japan □ DECHEMA e.V., Germany □ DLR - German Aerospace Center, Germany □ DTF Technology GmbH, Germany □ EADS Innovations Works, Germany □ Eurotechprom GmbH, Germany □ FEINGUSS BLANK GmbH, Germany □ Forschungszentrum Jülich GmbH, Germany □ Fundacion Tecnalia Research & Innovacion, Spain □ GE Aviation, USA □ German Aerospace Center, Institute of Materials Research, Germany □ GfE Fremat GmbH, Germany □ GfE Metalle und Materialien GmbH, Germany □ GfE Materials Technology, Inc., USA □ Graz University of Technology, Institute for Materials Science and Welding, Austria □ GSI mbH, NL SLV München, Germany □ Hanseatische Waren Handelsgesellschaft mbH & Co. KG, Germany □ Helmholtz Zentrum Geesthacht, Germany □ Helmholtz-Zentrum Dresden-Rossendorf e.V., Germany □ Hochschule Landshut, Germany □ HZDR, Institut für Ionenstrahlphysik und Materialforschung, Germany □ IHI Castings Co., Ltd. , Japan □ IHI Charging Systems International GmbH Germany □ IHI Corporation, Japan □ Institute for Metals Superplasticity Problems of Russian Academy of Sciences,

Russian Federation □ Institute of Materials and Machine Mechanics, Slovak Academy of Sciences

Slovakia

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□ Karlsruher Institut für Technologie, Germany □ Kyoto University, Japan □ Leibniz Institut für Festkörper und Werkstoffforschung, Germany □ Leistritz Turbinenkomponenten Remscheid GmbH, Germany □ Leistritz Turbomaschinen Technik GmbH, Germany □ Linn High Therm GmbH, Germany □ Luoyang Sunrui Ti Precision Casting Co., Ltd., China □ MAN Diesel & Turbo SE, Germany □ Max-Planck-Institut für Eisenforschung GmbH, Germany □ Montanuniversität Leoben, Department of Physical Metallurgy and Materials Testing,

Austria □ MTU Aero Engines GmbH, Germany □ NPP Technopark AT, Russian Federation □ OAO UMPO, Russian Federation □ Ohio Regents Eminent Scholar and Professor Department of Materials Science and

Engineering The Ohio State University, USA □ ONERA, France □ PCC Airfoils LLC, USA □ Politecnico di Milano, Italy □ Politecnico di Torino, Italy □ Pratt & Whitney, USA □ Robert Bosch GmbH, Germany □ Rolls-Royce Deutschland, Germany □ Rolls-Royce plc, United Kingdom □ RTI International Metals, Inc. , USA □ RWTH Aachen, IME Metallurgische Prozesstechnik und Metallrecycling, Germany □ RWTH Aachen University, ISF - Welding and Joining Institute, Germany □ Schweißtechnische Lehr- und Versuchsanstalt SLV München, NL der GSI mbH,

Germany □ Snecma (SAFRAN), France □ State Key Laboratory of Powder Metallurgy, Central South University, China □ TARAMM, France □ Technische Universität Dresden, Germany □ TITAL GmbH, Germany □ Tohoku University, Japan □ Tokyo Institute of Technology, Japan □ TU Bergakademie Freiberg, Germany □ Turbomeca (SAFRAN), France □ Universidad Carlos III de Madrid / IMDEA Materiales, Spain □ Universität Siegen, Germany □ University of Birmingham, United Kingdom □ University of Sheffield, United Kingdom □ Volkswagen AG, Germany

Page 42 / 52


List of participants Surname First

name Company City Country Phone No. e-mail

Achtermann Matthias GfE Metalle und Materialien GmbH

Nürnberg Germany +49 911 9315 239 matthias.achtermann@ gfe.com

Ackelid Ulf Arcam AB Molndal Sweden +46 736002048, +46 317103200

[email protected]

Aguilar Julio Access e.V. Aachen Germany +49 241 8098000 welcome@ access-technology.de

Alexeev Evgeny All-Russian Institute of Aviation Materials

Moscow Russian Federation

+7 499 261 86 77 [email protected]

Altmüller Stefan Leistritz Turbinenkomponenten Remscheid GmbH

Remscheid Germany +49 2191 6940 178

[email protected]

Appel Ludwig GSI mbH, NL SLV München

München Germany [email protected]

Arai Mikiya IHI Corporation Tokyo Japan +81 42 568 7859 [email protected] Arcobello-Varlese

Francesca CENTRO SVILUPPO MATERIALI SPA

Roma Italy +39 06 5055785 [email protected]

Backhaus Alexander ISF - Welding and Joining Institute, RWTH Aachen University

Aachen Germany +49 241 8097240 backhaus@ isf.rwth-aachen.de

Bakerin Sergey OAO UMPO Ufa Russian Federation

[email protected]

Bartosinski Marek IME Metallurgische Prozesstechnik und Metallrecycling RWTH Aachen

Aachen Germany +49 0241 8095196

marek.bartosinski@ metallurgie.rwth-aachen.de

Bartsch Marion DLR - German Aerospace Center

Köln Germany +49 2203 601 2436

[email protected]

Bauer-Partenheimer

Knut Leistritz Turbinenkomponenten Remscheid GmbH


[email protected]

Baumgärtner Dr.

Marianne Leistritz Turbomaschinen Technik GmbH

Nürnberg Germany [email protected]

Bednarek Dr. Sylwia AGH University of Science and Technology

Poland

Belaygue Philippe Turbomeca (SAFRAN )

Boudes France philippe.belaygue@ turbomeca.fr

Betz Ulrich ALD Vacuum Technologies GmbH

Hanau Germany +49 6181 307 3203

[email protected]

Bewlay Bernard Ceramic & Metallurgy Technologies, GE Global Research

Niskayuna, NY 12309 USA

USA

Biamino Sara Politecnico di Torino Torino Italy +39 110904712 [email protected]

Billhofer Hans Linn High Therm GmbH

Eschenfelden Germany

Bitzer Ingo Feinguss Blank GmbH

Riedlingen Germany +49 7371 182 124 ingo.bitzer@ feinguss-blank.de

Blank Werner Feinguss Blank GmbH

Riedlingen Germany +49 7371 182 120 werner.blank@ feinguss-blank.de

Bolz Sebastian BTU - Cottbus, Lehrstuhl Metallkunde und Werkstofftechnik

Cottbus Germany +49 355695105 sebastian.bolz@ tu-cottbus.de

Bortolotto Dr. Laurent DECHEMA e.V., Karl-Winnacker-Institut

Frankfurt am Main

Germany +49 69 7564 485 [email protected]

Braun Reinhold DLR - German Aerospace Center

Köln Germany +49 2203 6012457

[email protected]

Burghardt Dr. Andreas Robert Bosch GmbH Gerlingen Germany andreas.burghardt@ de.bosch.com

Page 43 / 52


Surname First name

Company City Country Phone No. e-mail

Caudrelier Jean-Francois

ONERA Chatillon cedex

France +33 1 46 73 45 55 jean-francois.caudrelier@ onera.fr

Chen Zhi Qiang Luoyang Sunrui Ti Precision Casting Co., Ltd

Luoyang, Henan

China [email protected]

Chernova Liudmila German Aerospace Center, Institute of Materials Research

Köln Germany +49 2203 601 2823

[email protected]

Clayton Tony Borg Warner Turbo Systems

Bradford United Kingdom

+44 7736337084 [email protected]

Clemens Helmut Montanuniversität Leoben Department of Physical Metallurgy and Materials Testing,

Loeben Austria +43 38424024200 helmut.clemens@ unileoben.ac.at

Couret Alain CEMES-CNRS Toulouse Cedex

France +33 5 62 25 78 71 [email protected]

Cramer Dr. Heidi Schweißtechnische Lehr- und Versuchsanstalt SLV München, NL der GSI mbH

München Germany +49 89 12680264 [email protected]

Crist Ernest M. RTI International Metals

Niles, OH USA +1 330 544 7767 [email protected]

Cudel Christian BorgWarner Turbo Systems WorldWide Headquarters GmbH

Kirchheim-bolanden

Germany +49 6352 403 2148

[email protected]

Cupid Dr. Damian Karlsruher Institut für Technologie

Eggenstein-Leopoldshofen

Germany [email protected]

Dardenne Laurent TARAMM LABEGE France + 33 5 61 39 96 56

tarammmethodes@ wanadoo.fr

Das Gopal Pratt & Whitney East Hartford USA [email protected]

Decker David M. BorgWarner Turbo Systems

Arden, North Carolina

USA +1 828 654 2554 [email protected]

Dietrich Madeleine Forschungszentrum Jülich GmbH

Jülich Germany +49 2461 61 2622 [email protected]

Dixon Mark Rolls-Royce plc Derby United Kingdom

+44 1332 241273 [email protected]

Duda Cynthia IHI Charging Systems International GmbH

Heidelberg Germany +49 6221 3096 245

[email protected]

El-Chaikh Ali Universität Siegen Siegen Germany el-chaikh@ ifwt.mb.uni-siegen.de

Eßlinger Dr. Jörg MTU München München Germany [email protected] Filippini Dr. Mauro Politecnico di Milano Milano Italy +39 02 2399 8220 [email protected]

Foltz IV John W. ATI Wah Chang Albany, OR USA +1 541 926 4211 [email protected]

Fraser Hamish L.

Ohio Regents Eminent Scholar and Department of Materials Science and Engineering The Ohio State University

Columbus, OH 43210

USA [email protected]; fraser@ matsceng.ohio-state.edu

Friedle Dr. Simone DECHEMA e.V. Frankfurt am Main

Germany +49 69 7564-637 [email protected]

Friedrich Prof.

Bernd RWTH Aachen, IME Metallurgische Prozesstechnik und Metallrecycling

Aachen Germany +49 241 8095850 [email protected]

Gabalcová Zuzana Institute of Materials and Machine Mechanics, Slovak Academy of Sciences

Bratislava Slovakia +421 2 49268289 [email protected]

Page 44 / 52


Surname First name


Gabrisch Heike Helmholtz Zentrum Geesthacht

Geesthacht Germany +49 4152 872540 [email protected]

Gaiani Silvia AKRAPOVIČ d.d. Ivančna Gorica

Slovenia +38 641921672 [email protected]

Gebel Dr. Thoralf DTF Technology GmbH

Dresden Germany +49 351 5636234 [email protected]

Gebhard Susanne Rolls-Royce Deutschland

Blankenfelde-Mahlow

Germany +49 33708 6 1626 Susanne.Gebhard@ rolls-royce.com

Gennaro Paolo AVIOPROP S.r.l. San Pietro Mosezzo

Italy +39 0321 437520 paolo.gennaro@ avioprop.com

Giunta Salvatore Avio S.p.A. Rivalta Italy +39 011 00 82947 [email protected]

Güther Dr. Volker GfE Metalle und Materialien GmbH

Nürnberg Germany +49 911 9315 446 [email protected]

Habel Dr. Ulrike MTU Aero Engines GmbH


Halici Dilek Graz University of Technology, Institute for Materials Science and Welding

Graz Austria +433168737182 [email protected]

Haupt Dr. Frank GfE Fremat GmbH Freiberg Germany +49 3731 375430 [email protected] Hempel Robert Hanseatische Waren

Handelsgesellschaft mbH & Co. KG

Bremen Germany +49 421 16227 15 [email protected]

Henker Oliver AUDI AG Ingolstadt Germany +49 841 89 36059 [email protected] Heutling Dr. Falko MTU Aero Engines

GmbH München Germany [email protected]

Hillmeier Michael MTU Aero Engines München Germany +49 89 1489 8611 [email protected] Hoffmann Markus TU Bergakademie

Freiberg Freiberg Germany +49 3731 392428 Markus.Hoffmann@

iwt.tu-freiberg.de Honda Hiroshi IHI Castings Co., Ltd. Tokyo Japan +81 42 500 8394 [email protected] Hu Dawei University of

Birmingham Birmingham United

Kingdom +44 1214147840 [email protected]

Huang Aijun Rolls-Royce plc Derby, DE24 8BJ

United Kingdom


Imayev Valery Institute for Metals Superplasticity Problems of Russian Academy of Sciences

Ufa Russian Federation


Janschek Peter Leistritz Turbinenkomponenten Remscheid GmbH


[email protected]

Jarczyk Georg ALD Vacuum Technologies GmbH

Hanau Germany +49 6181 307 3541

[email protected]

Jurisevic Bostjan AKRAPOVIČ d.d. Ivančna Gorica

Slovenia +38 640 243 099 bostjan.jurisevic@ akrapovic.si

Kabir Mohammad Rizviul

German Aerospace Center

Köln Germany +49 22036012481 mohammad-rizviul.kabir@ dlr.de

Kättlitz Oliver Access e.V. Aachen Germany +49 241-1689022 welcome@ access-technology.de

Kelm Klemens German Aerospace Center, Institute of Materials Research

Köln Germany +49 2203 601 4608

[email protected]

Khayrullina Aygul NPP Technopark AT Ufa Russian Federation

[email protected]

Kishida Kyosuke Kyoto University Kyoto Japan +81 75 753 5461 kyosuke-kishida@ mtl.kyoto-u.ac.jp

Klose Joachim GfE Fremat GmbH Freiberg Germany +49 3731 375584 [email protected] Kolitsch Prof. Andreas HZDR, Institut für

Ionenstrahlphysik und Materialforschung

Dresden Germany [email protected]

Kortschak Josef Böhler Schmiedetechnik GmbH & Co KG

Kapfenberg Austria +43 664 8364920 josef.kortschak@ bohler-forging.com

Page 45 / 52


Surname First name


Kourtis Lampros University of Sheffield Sheffield United Kingdom

+44 7895588036 [email protected]

Koyanagi Yoshihiko Daido Castings Corp., Ltd.

Gifu Japan +81 573 68 6951 [email protected]

Kriegel Marion TU Bergakademie Freiberg

Freiberg Germany +49 3731 392899 mario.kriegel@ iww.tu-freiberg.de

Kubushiro Keiji IHI Corporation Yokohama Japan +81 45 759 2806 [email protected] Kucheryaev Victor All-Russian Institute

of Aviation Materials Moscow Russian

Federation +7 499 261 86 77 [email protected]

Kuss Dominik Borg Warner Turbo Systems GmbH

Kirchheim-bolanden

Germany [email protected]

Lagos Miguel Angel

Fundacion Tecnalia Research & Innovacion

Bizkaia Spain +34 902760000 [email protected]

Lapin Juraj Institute of Materials and Machine Mechanics, Slovak Academy of Sciences

Bratislava Slovakia +421 2 49268290 [email protected]

Lindemann Janny Brandenburg University of Technology

Cottbus Germany +49 355 692821 [email protected]

Liu Yong State Key Laboratory of Powder Metallurgy, Central South University

Changsha, Hunan

China +86 731 88836939

[email protected]

Löber Guido GfE Metalle und Materialien GmbH

Nürnberg Germany +49 911 9315 287 guido.lö[email protected]

Löber Lukas Leibniz Institut für Festkörper und Werkstoffforschung

Dresden Germany +49 351 4659503 [email protected]

Lorenz Uwe Helmholtz-Zentrum Geesthacht

Geesthacht Germany +49 4152 872512 [email protected]

Loretto Michael Henry

University of Birmingham

United Kingdom

+44 121 414 5214 [email protected]

Lukaszek-Solek Dr.

Aneta AGH University of Science and Technology

Poland

Marcillaud Céline Snecma (SAFRAN) Colombes France [email protected] Maruyama Kouichi Tohoku University Sendai Japan +81 22 795 7324 maruyama@

material.tohoku.ac.jp

Masset Dr. Patrick J. TU Bergakademie Freiberg

Freiberg Germany +49 3731 39 4810 Patrick.Masset@ vtc.tu-freiberg.de

May Cameron GfE Materials Technology, Inc.

Wayne, PA 19087

USA +1 610 293 5811 [email protected]

Mayer Svea Montanuniversitaet Leoben Department of Physical Metallurgy and Materials Testing,

Loeben Austria +43 3842 402 4210

svea.mayer@ unileoben.ac.at

McQuay Paul PCC Airfoils LLC Portland, OR USA +1 503 459 9171 pmcquay@ pccstructurals.com

Medved Jurij AKRAPOVIČ d.d. Ivančna Gorica

Slovenia +386 1 78 78 405 [email protected]

Merenda Timo Continental Automotive GmbH

Regensburg Germany timo.merenda@ continental-corporation.com

Münch Günter Continental Grünstadt Germany guenter.muench@ continental-corporation.com

Muñoz Moreno

Rocío Universidad Carlos III de Madrid / IMDEA Materiales

Leganés (Madrid)

Spain +34 658574822 [email protected]

Neumann Beatries MAN Diesel & Turbo SE

Augsburg Germany [email protected]

Nicolai Hans-Peter

Tital GmbH Bestwig Germany +49 2904 981 125 [email protected]

Page 46 / 52


Surname First name


Niessen Nadine DLR - German Aerospace Center

Köln Germany +49 2203 601 3942

[email protected]

Nochovnaya Nadezda All-Russian Institute of Aviation Materials

Moscow Russian Federation

+7 499 261 86 77 [email protected]

Oehring Dr. Michael Helmholtz-Zentrum Geesthacht

Geesthacht Germany [email protected]

Palm Martin Max-Planck-Institut für Eisenforschung GmbH

Düsseldorf Germany +49 211 6792 226 [email protected]

Palm Frank EADS Innovations Works

München Germany +49 89 607 29782 [email protected]

Paul Jonathan Helmholtz Zentrum Geesthacht

Geesthacht Germany +49 4152872511 [email protected]

Pavlinich Sergey OAO UMPO Ufa Russian Federation

[email protected]

Perrut Mikael ONERA Chatilon cedex

France +33 1 46 73 4057 [email protected]

Petrov Oleg Eurotechprom GmbH Hamburg Germany [email protected]

Poletti Maria Cecilia

Graz University of Technology, Institute for Materials Science and Welding

Graz Austria +43 3168 737182 [email protected]

Pötzsch Anke GfE Fremat GmbH Freiberg Germany +49 3731 375 418 [email protected]

Preli Dr. Francis R.

Pratt & Whitney East Hardford USA +1 860-565-2158 [email protected]

Pyczak Florian Helmholtz-Zentrum Geesthacht

Geesthacht Germany +49 4152-87-2545 [email protected]

Rablbauer Dr. Ralf Volkswagen AG Wolfsburg Germany +49 152 01660112

ralf.rablbauer@ volkswagen.de

Reinsch Dr. Bernd Robert Bosch GmbH Gerlingen Germany bernd.reinsch@ de.bosch.com

Rérolle Romain Alcoa Power & Propulsion, Howmet SAS

Nanterre Cedex

France +33 1 41 91 12 32 [email protected]

Rothe Christiane GfE Fremat GmbH Freiberg Germany +49 3731 375 0 [email protected] Saage Holger Hochschule Landshut Landshut Germany +49 178 6237042 holger.saage@

fh-landshut.de Saari Henry Carleton University

Mechanical and Aerospace Engineering

Ottawa, Ontario

Canada +1 613 520 5684 [email protected]

Sabbadini Silvia Avio SpA Italy +39 011 0082862 silvia.sabbadini@ aviogroup.com

Schack Philipp TITAL GmbH Bestwig Germany [email protected]

Schall Gerald Borg Warner Engineering GmbH

Kirchheim-bolanden

Germany

Scherrer Frank Borg Warner Engineering GmbH

Kirchheim bolanden

Germany

Schloffer Martin Montanuniversität Leoben Department of Physical Metallurgy and Materials Testing

Loeben Austria +43 3842 402 4213

martin.schloffer@ unileoben.ac.at

Schmölzer Thomas Montanuniversität Leoben Department of Physical Metallurgy and Materials Testing

Loeben Austria +43 38424024267 thomas.schmoelzer@ unileoben.ac.at

Schödel Reinhard MAN Diesel & Turbo SE

Augsburg Germany [email protected]

Schütze Prof. Michael Dechema e.V. Frankfurt am Main


Page 47 / 52


Surname First name


Schwaighofer Emanuel Montanuniversität Leoben Department of Physical Metallurgy and Materials Testing,

Loeben Austria +43 3842 4024204

emanuel.schwaighofer@ unileoben.ac.at

Sehring Bjoern ALD Vacuum Technologies GmbH

Hanau Germany +49 6181 3073341

[email protected]

Seserko Pavel ALD Vacuum Technologies GmbH

Hanau Germany +49 6181 307 3227

[email protected]

Skrotzki Dr. Birgit BAM Bundesanstalt für Materialforschung und –prüfung

Berlin Germany +49 30 81041520 [email protected]

Smarsly Dr. Wilfried MTU Aero Engines GmbH


Sperenkova Svetlana Aviatech Ufa Russian Federation

sperenkova@ eurotechprom.com

Spiess Peter IME Metallurgische Prozesstechnik und Metallrecycling

Aachen Germany +49 241 80 95193 pspiess@ ime-aachen.de

Stockinger Martin Böhler Schmiedetechnik GmbH & Co KG

Kapfenberg Austria + 43 3862207166 martin.stockinger@ bohler-forging.com

Stöcker Christian Tital GmbH Bestwig Germany Stoyanov Todor Access e.V. Aachen Germany +49 241 8098000 welcome@

access-technology.de

Straubel Ariane Technische Universität Dresden

Dresden Germany +49 35146337519 ariane.straubel@ tu-dresden.de

Strelbitski Jürgen Borg Warner Engineering GmbH

Kirchheim-bolanden

Germany +49 6352 403 2674

fscherrer@ borgwarner.com.de

Takeyama Masao Tokyo Institute of Technology

Tokyo Japan +81 3 5734 3138 [email protected]

Third Noah PCC Airfoils Portland, OR USA +1 503 353 1006 [email protected]

Thomas Martin Continental Automotive GmbH

Regensburg Germany martin.thomas@ continental-corporation.com

Thomas Marc ONERA Châtillon France +33 1 46 73 44 75 [email protected]

Voigt Dr. Patrick Dinslaken Germany [email protected]

Wallis Dr. Ernst GfE Metalle und Materialien GmbH

Nürnberg Germany +49 911 9315 400 [email protected]

Wang Li Helmholtz Zentrum Geesthacht

Geesthacht Germany +49 4152-87-2540 [email protected]

Wege Robert MTU Aero Engines München Germany +49 89 1489 4390 [email protected]

Weimer Michael GE Aviation Cincinnati, OH USA [email protected]

Windsheimer Hans Linn High Therm GmbH


Yankov Dr. Rossen Helmholtz-Zentrum Dresden-Rossendorf e.V.

Dresden Germany +49 351 260 2531 [email protected]

Yegorov Anton Aviatech Ufa Russian Federation

[email protected]

Yu Kuang-O (Oscar)

RTI International Metals, Inc.

Niles OH USA +1 330 544 7657 [email protected]

Zhang Ji China Iron and Steel Research Institute Group

Beijing China +86 10 62182203 [email protected]

Zhou Hong Qiang

Luoyang Sunrui Ti Precision Casting Co., Ltd.

Luoyang, Henan

China +86 379 67256072

[email protected] [email protected]

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Notes

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