Capturing The Competing Influence Of Thermal And Mechanical Loads On The Strain Of Turbine Blade Coatings Via High Energy X-Rays

Keywords

Synchrotron; Thermal barrier coatings; Thermal gradient mechanical load

Abstract

This paper presents findings of synchrotron diffraction measurements on tubular specimens with a thermal barrier coating (TBC) system applied by electron beam physical vapor deposition (EB-PVD), having a thermally grown oxide (TGO) layer due to aging in hot air. The diffraction measurements were in situ while applying a thermal cycle with high temperature holds at 1000 °C and varying internal air cooling mass flow and mechanical load. It was observed that, during high temperature holds at 1000 °C, the TGO strain approached zero if no mechanical load or internal cooling was applied. When applying a mechanical load, the TGO in-plane strain (e22) changed to tensile and the out of plane TGO strain (e11) became compressive. The addition of internal cooling induced a thermal gradient, yielding a competing effect, driving the e22 strain to compressive and e11 strain to tensile. Quantifying TGO strain variations in response to competing factors will provide a path to controlling the TGO strain, and further improving the lifetime assessment and durability design strategies for TBC systems.

Publication Date

1-1-2018

Publication Title

Coatings

Volume

8

Issue

9

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.3390/COATINGS8090320

Socpus ID

85069759701 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/85069759701

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