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In-situ ESEM study of thermo-mechanical fatigue crack propagation

Jacobsson, Lars LU ; Persson, Christer LU and Melin, Solveig LU (2008) In Materials Science & Engineering: A 496(1-2). p.200-208
Abstract
An experimental procedure to determine crack propagation rates under thermo-mechanical loading is presented. The experiments were conducted in-situ within an environmental scanning electron microscope, and images of the crack tip region were taken throughout the load cycles. The mechanical load was provided by a load controlled electrically driven load stage. Thermal heating of the crack region was provided by means of resistance heating, and cooling by water flowing through the grips holding the specimen. In-phase experiments with the mechanical load following the temperature, as well as out-of-phase experiments with maximum mechanical load coinciding with minimum temperature, were conducted. Temperature cycles with a range from 300... (More)
An experimental procedure to determine crack propagation rates under thermo-mechanical loading is presented. The experiments were conducted in-situ within an environmental scanning electron microscope, and images of the crack tip region were taken throughout the load cycles. The mechanical load was provided by a load controlled electrically driven load stage. Thermal heating of the crack region was provided by means of resistance heating, and cooling by water flowing through the grips holding the specimen. In-phase experiments with the mechanical load following the temperature, as well as out-of-phase experiments with maximum mechanical load coinciding with minimum temperature, were conducted. Temperature cycles with a range from 300 degrees C to 550 degrees C, and from 300 degrees C to 630 degrees C with cycle times of 55 s and 75 s, respectively, were performed. Crack propagation rates as well as fracture surface morphologies were compared with corresponding results obtained under iso-thermal conditions at 550 degrees C and 630 degrees C. It was found that the temperature at which maximum mechanical load was applied was decisive for both the crack propagation rate and the fracture surface morphology, regardless of whether the temperature was cycled or kept constant. The study indicates that iso-thermal fatigue propagation data can be used to predict crack propagation rates provided that iso-thermal data are taken from the temperature at which the mechanical load peaks are known. (C) 2008 Elsevier B.V. All rights reserved. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Inconel 718, propagation, Crack, Thermo-mechanical fatigue, Scanning electron microscope
in
Materials Science & Engineering: A
volume
496
issue
1-2
pages
200 - 208
publisher
Elsevier
external identifiers
  • wos:000260639400024
  • scopus:51749112241
ISSN
1873-4936
DOI
10.1016/j.msea.2008.05.023
language
English
LU publication?
yes
id
cfecc39d-d97b-4439-9806-e61c95c5e3ca (old id 1283024)
date added to LUP
2009-02-10 12:57:12
date last changed
2017-02-19 03:24:35
@article{cfecc39d-d97b-4439-9806-e61c95c5e3ca,
  abstract     = {An experimental procedure to determine crack propagation rates under thermo-mechanical loading is presented. The experiments were conducted in-situ within an environmental scanning electron microscope, and images of the crack tip region were taken throughout the load cycles. The mechanical load was provided by a load controlled electrically driven load stage. Thermal heating of the crack region was provided by means of resistance heating, and cooling by water flowing through the grips holding the specimen. In-phase experiments with the mechanical load following the temperature, as well as out-of-phase experiments with maximum mechanical load coinciding with minimum temperature, were conducted. Temperature cycles with a range from 300 degrees C to 550 degrees C, and from 300 degrees C to 630 degrees C with cycle times of 55 s and 75 s, respectively, were performed. Crack propagation rates as well as fracture surface morphologies were compared with corresponding results obtained under iso-thermal conditions at 550 degrees C and 630 degrees C. It was found that the temperature at which maximum mechanical load was applied was decisive for both the crack propagation rate and the fracture surface morphology, regardless of whether the temperature was cycled or kept constant. The study indicates that iso-thermal fatigue propagation data can be used to predict crack propagation rates provided that iso-thermal data are taken from the temperature at which the mechanical load peaks are known. (C) 2008 Elsevier B.V. All rights reserved.},
  author       = {Jacobsson, Lars and Persson, Christer and Melin, Solveig},
  issn         = {1873-4936},
  keyword      = {Inconel 718,propagation,Crack,Thermo-mechanical fatigue,Scanning electron microscope},
  language     = {eng},
  number       = {1-2},
  pages        = {200--208},
  publisher    = {Elsevier},
  series       = {Materials Science & Engineering: A},
  title        = {In-situ ESEM study of thermo-mechanical fatigue crack propagation},
  url          = {http://dx.doi.org/10.1016/j.msea.2008.05.023},
  volume       = {496},
  year         = {2008},
}