Publication detail
Assessment of Extrinsic Crack Tip Shielding in Austenitic Steel near Fatigue Threshold
POKLUDA, J. KONDO, Y. SLÁMEČKA, K. ŠANDERA, P. HORNÍKOVÁ, J.
Czech title
Hodnocení vnějšího stínění špice trhliny v austenitické oceli v okolí prahové hodnoty
English title
Assessment of Extrinsic Crack Tip Shielding in Austenitic Steel near Fatigue Threshold
Type
journal article in Web of Science
Language
en
Original abstract
Asymmetric arrangements of stored crack-wake dislocations and low values of the size ratio SR, the plastic zone size / the characteristic microstructural distance, were found to be of basic importance for the shear misfit of crack flanks causing the roughness-induced crack closure in case of plain strain conditions. The crack wake dislocations produce also the plasticity induced crack closure as a result of a near-tip mismatch perpendicular to crack flanks. According to a recently published theoretical concept, an estimation of these extrinsic shielding effects in the threshold re-gion of fatigue crack propagation was made for austenitic steel of Japan provenience. Related fa-tigue experiments were based on a standard load shedding technique associated with monitoring of the crack closure level. The surface roughness was analysed by means of the optical chromatogra-phy that enables a 3D reconstruction of fracture morphology. Calculated and measured effective threshold values of about 2.2 MPa.m1/2 are practically identical. Total levels of the extrinsic tough-ening induced by the austenitic microstructure are rather low when compared to those identified in ferritic- and ferritic-austenitic steels.
Czech abstract
Asymmetric arrangements of stored crack-wake dislocations and low values of the size ratio SR, the plastic zone size / the characteristic microstructural distance, were found to be of basic importance for the shear misfit of crack flanks causing the roughness-induced crack closure in case of plain strain conditions. The crack wake dislocations produce also the plasticity induced crack closure as a result of a near-tip mismatch perpendicular to crack flanks. According to a recently published theoretical concept, an estimation of these extrinsic shielding effects in the threshold re-gion of fatigue crack propagation was made for austenitic steel of Japan provenience. Related fa-tigue experiments were based on a standard load shedding technique associated with monitoring of the crack closure level. The surface roughness was analysed by means of the optical chromatogra-phy that enables a 3D reconstruction of fracture morphology. Calculated and measured effective threshold values of about 2.2 MPa.m1/2 are practically identical. Total levels of the extrinsic tough-ening induced by the austenitic microstructure are rather low when compared to those identified in ferritic- and ferritic-austenitic steels.
English abstract
Asymmetric arrangements of stored crack-wake dislocations and low values of the size ratio SR, the plastic zone size / the characteristic microstructural distance, were found to be of basic importance for the shear misfit of crack flanks causing the roughness-induced crack closure in case of plain strain conditions. The crack wake dislocations produce also the plasticity induced crack closure as a result of a near-tip mismatch perpendicular to crack flanks. According to a recently published theoretical concept, an estimation of these extrinsic shielding effects in the threshold re-gion of fatigue crack propagation was made for austenitic steel of Japan provenience. Related fa-tigue experiments were based on a standard load shedding technique associated with monitoring of the crack closure level. The surface roughness was analysed by means of the optical chromatogra-phy that enables a 3D reconstruction of fracture morphology. Calculated and measured effective threshold values of about 2.2 MPa.m1/2 are practically identical. Total levels of the extrinsic tough-ening induced by the austenitic microstructure are rather low when compared to those identified in ferritic- and ferritic-austenitic steels.
Keywords in Czech
vnější stínění špice trhliny, austenitická ocel, prahová hodnota
Keywords in English
Assessment, Extrinsic Crack Tip Shielding, Austenitic Steel, Fatigue Threshold
RIV year
2008
Released
02.07.2008
ISSN
1013-9826
Journal
Key Engineering Materials
Volume
385-387
Number
1
Pages from–to
49–52
Pages count
4
BIBTEX
@article{BUT47422,
author="Jaroslav {Pokluda} and Yoshiyuki {Kondo} and Karel {Slámečka} and Pavel {Šandera} and Jana {Horníková},
title="Assessment of Extrinsic Crack Tip Shielding in Austenitic Steel near Fatigue Threshold",
journal="Key Engineering Materials",
year="2008",
volume="385-387",
number="1",
month="July",
pages="49--52",
issn="1013-9826"
}