GKSS Forschungszentrum, Tuesday, 16-Mar-2010 06:26:45 CET
http://www.gkss.de/program/materials_systems/ti_al/index.html.de

TiAl alloys for Applications in High-Temperature Technologies

Impellers for superchargers from titanium aluminides are at the same time extremely light, corrosion resistant and of high-strength (picture ACCESS e.V., Aachen)Impellers for superchargers from titanium aluminides are at the same time extremely light, corrosion resistant and of high-strength (picture ACCESS e.V., Aachen)

In the area of light-weight materials for elevated temperatures intermetallic γ-titanium aluminides are aimed to replace conventionally used alloys. New aluminide alloys (designated as TNB) offer outstanding thermo-physical properties which make them superior on a density related basis to the currently used nickel-based superalloys up to temperatures of 750-800°C. Industry requires extensive metallurgical research in the field of commercial TiAl based products for a quantitative, physically-based understanding of the microstructure-properties relationship, which can be applied to controlling and optimising the manufacturing and performance of the components.

In Germany TiAl technology has made fast progress towards commercialisation over the last two years. Current developments are focused on the production of components for the aero-engine and automotive industry. Examples for commercial component developments are turbine blades, valves and turbocharger impellers. Metallurgical research in this field is mainly driven by the requirements of industry for a quantitative, physically-based understanding, which can be applied to control and optimise the component performance. Integration of the processing parameters into compositional and microstructural design is needed, not only to maximize the utility of the material, but also to provide the framework for production control.

Compressor rotor blades for an aero engine (Rolls-Royce Germany Ltd.) from a TiAl alloy patented by GKSS, which was manufactured in a public funded project by extrusion, forging and electro-chemical milling (partners: Rolls-Royce Deutschland Ltd & Co KG, Leistritz Turbinenkomponenten Remscheid GmbH, GfE Metalle und Materialien GmbH, Leistritz Turbomaschinen Technik GmbH)Compressor rotor blades for an aero engine (Rolls-Royce Germany Ltd.) from a TiAl alloy patented by GKSS, which was manufactured in a public funded project by extrusion, forging and electro-chemical milling (partners: Rolls-Royce Deutschland Ltd & Co KG, Leistritz Turbinenkomponenten Remscheid GmbH, GfE Metalle und Materialien GmbH, Leistritz Turbomaschinen Technik GmbH)

GKSS is involved in most of these activities in providing alloy compositions and constitutions, which are tailored for different processing routes, including casting, powder and hot-working technologies. In the next few years production scale-up and component certification play an important role and include a number of interconnected activities with industry partners. Material performance will be assessed by thorough defect analysis including non-destructive inspection procedures. Rig testing of selected components will be performed in order to demonstrate their cyclic and overspeed capability. It is important to emphasize that the tests must be conducted on material taken from full-scale production hardware. Much concern with limited ductility and fracture toughness imposes significant restrictions on acceptable technologies.In this context, early recognition of the key risks to implementation must be identified, and appropriate mitigation strategies devised.

Contact

Dr. Michael Oehring

Telefon: +49 (4152) 87-2672

Telefax: +49 (4152) 87-2534

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