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Advanced Analysis Tools To Predict Failure Mechanisms In TBC Coated& Uncoated Single Crystal Superalloys

Objective



The increasingly severe and complex mechanical and thermal loading conditions which gas turbine blades are being subjected to often lead to fatigue cracks initiating in regions where cyclic plasticity highly localizes, due to mechanical and thermal cyclic stressing. Moreover, creep damage is observed due to high temperatures dwell times, which also generate oxidation damaging processes. The complexity of such processes is further underlined by the interaction between cyclic plasticity damage and creep damage. Current and future engine developments rely on thermal barrier coatings (TBC) applied on some strategic places of components to raise turbine inlet temperatures and hence increase thermodynamic efficiency. Substrate damage, oxidation and TBC degradation can however significantly reduce component life time.
The aim of this basis research proposal is to develop tools for life assessment of single crystal superalloys components. Two distinct aspects will be considered for damage analysis:
fatigue damage of uncoated single crystal;
degradation of the thermal barrier coating (TBC) itself.

The two aspects will be studied in parallel, as they involve completely different damage mechanisms. The study will provide the physical basis to model the damage by taking into account the role of the various interactions with the microstructure. Micromechanical and macroscopical models will be developed.

The specific objectives of the work programme are to develop: a basic understanding of the dominant high temperature degradation and damage mechanisms in coated and uncoated monocrystalline Ni base superalloy components used in gas turbine applications,
the development of mechanical models at both the mesoscopic and macroscopic levels, together with computational tools for life assessments,
the validation of the life assessment method on the basis of structure analyses.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

Office National d'Etudes et de Recherches A?rospatiales
Address
29 Avenue De La Division Leclerc
92322 Châtillon
France

Participants (6)

ALSTOM POWER UK LTD.
United Kingdom
Address
Lichfield Road
ST17 4LN Stafford
ASSOCIATION POUR LA RECHERCHE ET LE DEVELOPPEMENT DES METHODES ET PROCESSUS INDUSTRIELS
France
Address
Enceinte Snecma Evry-corbeil 032
91003 Evry
Bundesanstalt für Materialforschung und Materialprüfung
Germany
Address
87,Unter Den Eichen
12205 Berlin
IMPERIAL COLLEGE OF SCIENCE, TECHNOLOGY AND MEDICINE
United Kingdom
Address
Exhibition Road
SW7 2BX London
Siemens AG
Germany
Address
35,Wiesenstraße 35
45466 Mülheim An Der Ruhr
Volvo Aero Corporation AB
Sweden
Address

461 81 Trollhättan