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Interface fracture toughness in thermal barrier coatings by cross-sectional indentation
journal contribution
posted on 2023-06-08, 15:39 authored by Xin Wang, Chang WangChang Wang, Alan AtkinsonThe interface fracture toughness of thermal barrier coatings (TBCs) on high-pressure turbine blades manufactured by electron beam physical vapour deposition was measured by a cross-sectional indentation (CSI) method. Scanning electron microscopy and luminescence mapping were employed to reveal that coating delamination induced by CSI was predominantly along the thermally grown oxide–bond coat interface and the shape of the delaminated area was approximately semicircular. The critical energy release rate (Gc)for delamination was calculated based on a clamped circular plate model. Analysis of the stored energy release revealed that the residual stresses in the coating do not contribute to the total energy release rate provided that the delaminated area of the coating does not buckle. Therefore, for this method, detailed information of residual stresses is not necessary for the determination of interface fracture toughness. However, intercolumnar microfracture and shear displacement in the YSZ top coat can lead to significant overestimation of the interface fracture toughness in some situations. A method of specimen preparation is described to inhibit these effects. The interface fracture resistance of the TBCs was found to be 29 ± 9 J/m-2 after between 35 and 100 thermal cycles (from room temperature to 1150 °C with 1 h duration.
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Publication status
- Published
Journal
Acta MaterialiaISSN
1359-6454Publisher
ElsevierExternal DOI
Issue
17Volume
60Page range
6152-6163Department affiliated with
- Engineering and Design Publications
Full text available
- No
Peer reviewed?
- Yes
Legacy Posted Date
2013-09-11Usage metrics
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