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In-situ SEM study of fatigue crack growth behaviour in IN718

Andersson, Henrik LU and Persson, Christer LU (2004) In International Journal of Fatigue 26(3). p.211-219
Abstract
Fatigue crack growth experiments on Inconel 718 have been performed in a scanning electron microscope at room temperature. The investigated cracks were approximately 1-3 mm long and the samples used were thin 10 mm wide plates. The crack opening stress was found to vary significantly, even in the Paris region, for a constant stress ratio. Crack growth was predominantly found to be either growth on slip planes in a shearing mode, or linking after formation of microcracks ahead of the main crack, which do not require detectable crack opening. A rough crack surface indicates that at room temperature roughness induced crack closure is significant even in the midst of the Paris region, at higher stress intensity factor levels than anticipated.... (More)
Fatigue crack growth experiments on Inconel 718 have been performed in a scanning electron microscope at room temperature. The investigated cracks were approximately 1-3 mm long and the samples used were thin 10 mm wide plates. The crack opening stress was found to vary significantly, even in the Paris region, for a constant stress ratio. Crack growth was predominantly found to be either growth on slip planes in a shearing mode, or linking after formation of microcracks ahead of the main crack, which do not require detectable crack opening. A rough crack surface indicates that at room temperature roughness induced crack closure is significant even in the midst of the Paris region, at higher stress intensity factor levels than anticipated. A post experimental examination of the fracture surfaces revealed that a striation forming mechanism was not active at short cracks, but as crack length increased, the occurrence of striations increased in the interior of the specimen. No striations were found in the grains at the specimen surface. As multiple crack growth mechanisms are active, fatigue crack rate predictions need to take all different mechanisms into account to improve accuracy. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
regime, Paris, SEM, in-situ fatigue experiment, IN718, crack closure, fatigue, slip bands
in
International Journal of Fatigue
volume
26
issue
3
pages
211 - 219
publisher
Elsevier
external identifiers
  • wos:000188375900002
  • scopus:0345375305
ISSN
1879-3452
DOI
10.1016/S0142-1123(03)00172-5
language
English
LU publication?
yes
id
be9e353f-7945-4cb6-ad70-7565d302a61a (old id 289052)
date added to LUP
2007-10-16 12:41:30
date last changed
2017-12-10 03:42:07
@article{be9e353f-7945-4cb6-ad70-7565d302a61a,
  abstract     = {Fatigue crack growth experiments on Inconel 718 have been performed in a scanning electron microscope at room temperature. The investigated cracks were approximately 1-3 mm long and the samples used were thin 10 mm wide plates. The crack opening stress was found to vary significantly, even in the Paris region, for a constant stress ratio. Crack growth was predominantly found to be either growth on slip planes in a shearing mode, or linking after formation of microcracks ahead of the main crack, which do not require detectable crack opening. A rough crack surface indicates that at room temperature roughness induced crack closure is significant even in the midst of the Paris region, at higher stress intensity factor levels than anticipated. A post experimental examination of the fracture surfaces revealed that a striation forming mechanism was not active at short cracks, but as crack length increased, the occurrence of striations increased in the interior of the specimen. No striations were found in the grains at the specimen surface. As multiple crack growth mechanisms are active, fatigue crack rate predictions need to take all different mechanisms into account to improve accuracy.},
  author       = {Andersson, Henrik and Persson, Christer},
  issn         = {1879-3452},
  keyword      = {regime,Paris,SEM,in-situ fatigue experiment,IN718,crack closure,fatigue,slip bands},
  language     = {eng},
  number       = {3},
  pages        = {211--219},
  publisher    = {Elsevier},
  series       = {International Journal of Fatigue},
  title        = {In-situ SEM study of fatigue crack growth behaviour in IN718},
  url          = {http://dx.doi.org/10.1016/S0142-1123(03)00172-5},
  volume       = {26},
  year         = {2004},
}