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In-situ synchrotron X-ray strain measurements in TBC systems during thermal mechanical cycling

Bartsch, Marion and Meid, Carla and Wischek, Janine and Karlsson, Anette M. and Knipe, Kevin and Manero, Albert and Raghavan, Seetha and Okasinski, John and Almer, Jonathan (2013) In-situ synchrotron X-ray strain measurements in TBC systems during thermal mechanical cycling. In: Proceedings of the 3rd Japanese - German international Workshop on Thermal Barrier Coatings (memory stick - contribution C5). Third Japanese-German TBC Workshop, 25.-27.Juni 2013, München, Deutschland.

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Abstract

Thermal barrier coatings (TBC) are applied on cooled gas turbine components. Between the heated and cooled surfaces a thermal gradient develops, resulting for constraint components in high multiaxial stresses, which may exceed stresses due to mechanical loading. In order to investigate the damage behaviour of TBC systems under close to reality conditions, thermal mechanical fatigue tests with controlled thermal gradients (TGMF-tests) were performed on coated tubular specimens. The specimen substrate was made from directionally solidified nickel base superalloy IN100 DS, and the coating system comprised a NiCoCrAlY bond coat and a ceramic top coat from partially stabilized zirconia. In TGMF testing specific damages occurred underneath the adherent ceramic top coat, evolving into fatigue cracks, which propagated primarily in the metallic bond coat parallel to the surface. To explain the initiation and evolution of these fatigue cracks, the thermo-mechanical response of the bond coat and the thermally grown oxide (TGO) between bond coat and ceramic top coat is examined and quantified through finite element analyses. The models include non-linear and time-dependent behaviour such as creep, TGO growth stress, and thermo-mechanical cyclic loading. The simulations suggest that stress redistribution due to creep can lead to tensile stresses in the TGO during TGMF testing that are large enough to initiate the cracks investigated. In order to get experimental data of the strain in the different layers of the coating system during TGMF-loading a test device has been assembled allowing in-situ strain measurements in the entire TBC system by means of synchrotron X-rays. Data analyses so far have shown that all layers could be identified, for all layers it is possible to measure strain qualitatively, and the TGO showed a texture. Goal of the ongoing work is the calculation of the full strain tensor in each layer for the entire thermal mechanical load cycle.

Item URL in elib:https://elib.dlr.de/83590/
Document Type:Conference or Workshop Item (Speech)
Title:In-situ synchrotron X-ray strain measurements in TBC systems during thermal mechanical cycling
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Bartsch, Marionmarion.bartsch (at) dlr.deUNSPECIFIED
Meid, CarlaDLR WF (ENM)UNSPECIFIED
Wischek, Janinejanine.wischek (at) dlr.deUNSPECIFIED
Karlsson, Anette M.Cleveland State University, Ohio, USAUNSPECIFIED
Knipe, KevinUniversity of Central Florida, Orlando, FL, USAUNSPECIFIED
Manero, AlbertUniversity of Central Florida, Orlando, FL, USAUNSPECIFIED
Raghavan, SeethaUniversity of Central Florida, Orlando, FL, USAUNSPECIFIED
Okasinski, JohnAdvanced Photon Source, Argonne National Laboratory, Argonne, IllinoisUNSPECIFIED
Almer, JonathanAdvanced Photon Source, Argonne National Laboratory, Argonne, IllinoisUNSPECIFIED
Date:27 June 2013
Journal or Publication Title:Proceedings of the 3rd Japanese - German international Workshop on Thermal Barrier Coatings (memory stick - contribution C5)
Refereed publication:No
Open Access:Yes
Gold Open Access:No
In SCOPUS:No
In ISI Web of Science:No
Status:Published
Keywords:Thermal Barrier Coating, TBC, thermal mechanical cycling, thermal gradient, TGMF, X-ray diffraction, in situ strain measurement, synchrotron radiation
Event Title:Third Japanese-German TBC Workshop
Event Location:München, Deutschland
Event Type:international Conference
Event Dates:25.-27.Juni 2013
Organizer:Technische Universität Darmstadt
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Aeronautics
HGF - Program Themes:Propulsion Systems (old)
DLR - Research area:Aeronautics
DLR - Program:L ER - Engine Research
DLR - Research theme (Project):L - Virtual Engine and Validation Methods (old)
Location: Köln-Porz
Institutes and Institutions:Institute of Materials Research > Experimental and Numerical Methods
Deposited By: Bartsch, Dr.-Ing. Marion
Deposited On:29 Aug 2013 11:27
Last Modified:31 Jul 2019 19:41

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