Publication detail

Effect of Underload Cycles on Oxide-Induced Crack Closure Development in Cr-Mo Low-Alloy Steel

POKORNÝ, P. VOJTEK, T. JAMBOR, M. NÁHLÍK, L. HUTAŘ, P.

Original Title

Effect of Underload Cycles on Oxide-Induced Crack Closure Development in Cr-Mo Low-Alloy Steel

Type

journal article in Web of Science

Language

English

Original Abstract

Underload cycles with small load amplitudes below the fatigue crack growth threshold are dominantly considered as insignificant cycles without any influence on fatigue lifespan of engineering structural components. However, this paper shows that in some cases these underload cycles can retard the consequent crack propagation quite significantly. This phenomenon is a consequence of oxide-induced crack closure development during cyclic loading below the threshold. The experimentally described effect of fatigue crack growth retardation was supported by measurement of the width and the thickness of the oxide debris layer using the EDS technique and localized FIB cuts, respectively. Both the retardation effect and the amount of oxide debris were larger for higher number and larger amplitudes of the applied underload cycles. Crack closure measurement revealed a gradual increase of the closure level during underload cycling. Specimens tested in low air humidity, as well as specimens left with the crack open for the same time as that needed for application of the underload cycles, revealed no retardation effect. The results can improve our understanding of environmental effects on fatigue crack propagation and understanding the differences between the results of laboratory testing and the fatigue lives of components in service.

Keywords

underload cycles; crack closure; threshold; fatigue crack growth; oxidation; EA4T steel

Authors

POKORNÝ, P.; VOJTEK, T.; JAMBOR, M.; NÁHLÍK, L.; HUTAŘ, P.

Released

1. 5. 2021

Publisher

MDPI

Location

BASEL

ISBN

1996-1944

Periodical

Materials

Year of study

14

Number

10

State

Swiss Confederation

Pages from

1

Pages to

22

Pages count

22

URL

https://www.mdpi.com/1996-1944/14/10/2530

Full text in the Digital Library

http://hdl.handle.net/11012/202975

BibTex

@article{BUT172960,
  author="Pavel {Pokorný} and Tomáš {Vojtek} and Michal {Jambor} and Luboš {Náhlík} and Pavel {Hutař}",
  title="Effect of Underload Cycles on Oxide-Induced Crack Closure Development in Cr-Mo Low-Alloy Steel",
  journal="Materials",
  year="2021",
  volume="14",
  number="10",
  pages="1--22",
  doi="10.3390/ma14102530",
  issn="1996-1944",
  url="https://www.mdpi.com/1996-1944/14/10/2530"
}