Title

Effect Of Pre-Exposure On Crack Initiation Life Of A Directionally Solidified Ni-Base Superalloy

Keywords

Creep; Directionally solidified; Ni-base superalloy; Pre-exposure; Pre-strain

Abstract

Blades and vanes are just two of several industrial gas turbine (IGT) components often subjected to long periods of elevated temperature before, during, and after high stress operating conditions. In these systems, cyclic loading is induced by repeated start-ups, firings, and shut-down ramps. Combinations of complex thermal and mechanical service conditions in the presence of aggressive reactants facilitate crack initiation via oxide spike formation. In the current study, the effect of pre-exposure on the oxide spiking damage mechanism and crack initiation life is characterized for a representative directionally solidified (DS) Ni-base superalloy, e.g. DS GTD-111. Comparisons of unexposed and pre-exposed samples reveal that 100 h of either creep pre-strain and/or thermal pre-exposure strongly influences the dominant damage mechanism that leads to crack initiation under subsequent fatigue cycling. A mechanistic model for crack initiation is modified to capture the influence of pre-exposure on life. © 2008 Elsevier Ltd. All rights reserved.

Publication Date

2-1-2009

Publication Title

International Journal of Fatigue

Volume

31

Issue

2

Number of Pages

393-401

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1016/j.ijfatigue.2008.07.009

Socpus ID

55949117778 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/55949117778

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