Title

Microstructural Evolution Of Durable Thermal Barrier Coatings With Hf And/Or Y Modified Cmsx-4™ Superalloy Substrates

Keywords

Compositional modification; Lifetime assessment; Microstructure; Parabolic growth rate constant; Rumpling; Thermal barrier coating; Thermally grown oxide

Abstract

Thermal cyclic lifetime and microstructural degradation of thermal barrier coatings (TBCs) with (Ni,Pt)Al bond coat and Hf- and/or Y-modified CSMX-4 superalloy substrates were examined. Thermal cyclic lifetime of TBCs was measured using a furnace thermal cycle test that consisted of 10-minute heat-up, 50-minute dwell at 1135°C, and 10-minute forced-air-quench. TBC lifetime was observed to improve from 600 cycles to over 3200 cycles with appropriate Hf- and/or Y-alloying of CMSX-4 superalloys. This significant improvement in TBC lifetime is the highest reported lifetime in literature with similar testing parameters. Cross-sectional microstructure of TBC specimens were examined by scanning electron microscopy (SEM) after the spallation failure, While undulation of TGO/bond coat interface (e.g., rumpling and racheting) was observed to be main damage mechanisms for TBCs on baseline CMSX-4, the same interface remained relatively flat for durable TBCs on Hf- and/or Y-modified CSMX-4. The parabolic growth constant of the TGO scale was slightly lower for TBCs with Hfand/or Y-modified CSMX-4.

Publication Date

1-1-2007

Publication Title

Materials Science Forum

Volume

539-543

Issue

PART 2

Number of Pages

1206-1211

Document Type

Article; Proceedings Paper

Personal Identifier

scopus

DOI Link

https://doi.org/10.4028/0-87849-428-6.1206

Socpus ID

38349045317 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/38349045317

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