Simulation of the effect of realistic surface textures on thermally induced topcoat stress fields by two-dimensional interface functions

Nordhorn, Christian; Mücke, Robert; Vaßen, Robert

doi:10.1016/j.surfcoat.2014.09.032

Cited by 12 publications

(6 citation statements)

References 19 publications

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“…In previous work done by Gupta et al, it was observed that a 3D profile could enable the possibility to capture a global field with better visualisation of the results while the 2D simulations provide limited information since the results can vary significantly depending on the location of the microstructure cross-section analysed even across a few micrometres [11]. Nordhorn et al performed analyses of realistic 3D and multiple 2D approximation models with parameters derived from surface roughness measurements [34]. It was observed that although the 2D models could accurately reflect TGO related features such as stress inversion, etc., they could not reflect the details of the stress distributions.…”

Section: D Domainmentioning

confidence: 99%

See 1 more Smart Citation

A diffusion-based oxide layer growth model using real interface roughness in thermal barrier coatings for lifetime assessment

Gupta

Eriksson

Sand

et al. 2015

Surface and Coatings Technology

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Section: D Domainmentioning

confidence: 99%

“…It was observed that although the 2D models could accurately reflect TGO related features such as stress inversion, etc., they could not reflect the details of the stress distributions. The 3D model was found to be too complex to be replaced by a single 2D approximating function [34].…”

Section: D Domainmentioning

confidence: 99%

A diffusion-based oxide layer growth model using real interface roughness in thermal barrier coatings for lifetime assessment

Gupta

Eriksson

Sand

et al. 2015

Surface and Coatings Technology

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“…The TGO introduces additional stresses in the TBC system due to its different material properties especially the low thermal expansion coefficient. This stress increases with higher TGO thickness and promotes crack propagation in the TGO and the top coat close to the TGO [7,18]. These cracks weaken the top coat-bond coat interface, or in a fracture mechanical approach reduce the critical energy release rate until the coating fails.…”

Section: Introductionmentioning

confidence: 99%

“…Compressive stress states hinder the cracks to link from peak to peak. Finally, the low thermal expansion coefficient of the TGO leads to tensile stresses at the valley of the bond coat, causing crack linking and finally failure of the coating [18,19,23].…”

Section: Introductionmentioning

confidence: 99%

Superior cyclic life of thermal barrier coatings with advanced bond coats on single-crystal superalloys

Vorkötter

Mack

Guillon

et al. 2019

Surface and Coatings Technology

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Advanced thermal barrier coatings are essential to further increase the efficiency of gas turbine engines. One limiting factor of the TBC lifetime is the temperature dependent formation of the thermally grown oxide (TGO) during thermal exposure resulting in critical stress levels at the top coat -bond coat interface. Oxide dispersion strengthened (ODS) bond coats demonstrated slower oxygen scale growth during thermal exposure in comparison to standard bond coats.In this study for the first time TBC samples on single-crystal substrates (comparable to CMSX4) with thin ODS Co-based flash coats on the same Co-based bond coat (Amdry 995) and a porous atmospherically plasma sprayed (APS) yttria stabilized zirconia (YSZ) topcoat were manufactured by thermal spray techniques and evaluated with respect to their thermal cyclic behavior. As the major performance test cyclic burner rigs, which can establish thermal conditions similar to those in gas turbines, were applied.TBC samples with the new material combination show superior performance compared to previous samples. Cross sections of the samples were analyzed by scanning electron and laser scanning microscopy. Lifetime data and failure mode of the samples are discussed with respect to material properties such as thermal expansion coefficients, microstructural changes and TGO growth.

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“…However, they are stopped at the valley locations, where there is compressive stress. Until a sufficiently thick TGO is formed during long-term operation, the resulting stress inversion leads to the extension of crack growth to the valley locations and ultimately to failure [21].…”

Section: Introductionmentioning

confidence: 99%

Effect of Low-CTE Oxide-Dispersion-Strengthened Bond Coats on Columnar-Structured YSZ Coatings

et al. 2022

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Thermal barrier coatings (TBCs) are commonly used to protect gas turbine components from high temperatures and oxidation. Such coatings consist of ceramic top coats and metallic bond coats. The mismatch in thermal expansion of the top coat, the bond coat and the component material is one main factor leading to the failure of the coating system. Columnar-structured top coats offer an enhanced tolerance to the strain during thermal cycling. On a flat bond coated surface, these TBCs reach higher thermal cycling performance. However, on rough surfaces, as used for thermal spray coatings, the performance of these thermal barrier coatings seems to be restricted or even stays below the performance of atmospheric-plasma-sprayed (APS) thermal barrier coatings. This low performance is linked to out-of-plane stresses at the interface between the top coat and the bond coat. In this study, a thin additional oxide-dispersion-strengthened (ODS) bond coat with high alumina content provides a reduced mismatch of the coefficient of thermal expansion (CTE) between the top coat and the bond coat. Columnar suspension plasma sprayed (SPS), yttria-stabilized zirconia (YSZ) TBCs were combined with low-CTE ODS bond coats. The behavior of these TBCs was characterized with respect to thermal cycling performance and degradation in a burner-rig facility. The comparison showed an up-to-four-fold increase in the performance of the new system.

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Simulation of the effect of realistic surface textures on thermally induced topcoat stress fields by two-dimensional interface functions

Cited by 12 publications

References 19 publications

A diffusion-based oxide layer growth model using real interface roughness in thermal barrier coatings for lifetime assessment

A diffusion-based oxide layer growth model using real interface roughness in thermal barrier coatings for lifetime assessment

Superior cyclic life of thermal barrier coatings with advanced bond coats on single-crystal superalloys

Effect of Low-CTE Oxide-Dispersion-Strengthened Bond Coats on Columnar-Structured YSZ Coatings

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