Fatigue behavior of a freestanding Pt-aluminide (PtAl) bond coat at ambient temperature

Kumawat, MK and Sarkar, R and Jayaram, V and Alam, MZ (2021) Fatigue behavior of a freestanding Pt-aluminide (PtAl) bond coat at ambient temperature. In: Surface and Coatings Technology, 427 .

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Abstract

The intermetallic B2-NiAl based diffusion Pt-aluminide (PtAl) bond coat is applied on aero-engine components. The coating is prone to brittle fracture, which necessitates the evaluation of its fatigue behavior. In the present study, micro-fatigue testing is conducted on freestanding 70 μm thick PtAl coating at ambient temperature. The fatigue life is as low as 30,000 cycles and exceeds 106 cycles above and below the endurance limit of 248 MPa. High dislocation density, dislocation cells, and dislocation-dislocation/dislocation-precipitate interactions induce strain hardening in the coating. Micro-voids initiate by de-cohesion of precipitate/B2-matrix interface in the heavily precipitated interdiffusion zone of the coating. The intergranular propagation of micro-cracks, developed by micro-void coalescence, causes failure. © 2021 Elsevier B.V.

Item Type:	Journal Article
Publication:	Surface and Coatings Technology
Publisher:	Elsevier B.V.
Additional Information:	The copyright for this article belongs to Elsevier B.V.
Keywords:	Aircraft engines; Aluminum alloys; Binary alloys; Fatigue testing; Intermetallics; Nickel alloys; Nickel coatings; Platinum alloys; Strain hardening; Superalloys; Textures; Thermal barrier coatings; Thermal fatigue; Titanium alloys, Aero-engine components; Aluminides; Bond coats; Fatigue behaviour; Freestanding pt-aluminide bond coat; Micro voids; Nickel aluminide intermetallics; Small scale; Small scale testing; Thermal barrier coating, Temperature
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	28 Nov 2021 09:33
Last Modified:	28 Nov 2021 09:33
URI:	http://eprints.iisc.ac.in/id/eprint/70404

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