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Titel: Crack initiation and propagation during high-temperature fatigue of oxide dispersion-strengthened superalloys
Verfasser: Elzey, D. M.
Arzt, Eduard
Sprache: Englisch
Erscheinungsjahr: 1991
Quelle: Metallurgical transactions / A. - 22. 1991, 4, S. 837-851
SWD-Schlagwörter: Rissausbreitung
Materialermüdung
Hochtemperatur
Mechanische Eigenschaft
Nickellegierung
DDC-Sachgruppe: 620 Ingenieurwissenschaften und Maschinenbau
Dokumentart : Journalartikel
Kurzfassung: The mechanisms of crack initiation and propagation have been investigated in two oxide dispersion-strengthened (ODS) Ni-base superalloys under conditions of symmetric low-cycle fatigue (LCF) and creep-fatigue. The behavior of both ODS alloys is compared with that of conventional alloys of otherwise similar composition. While the improvement in fatigue resistance previously reported for ODS metals and alloys is confirmed by the present study for temperatures below about 0.6T m, the potential advantage of dispersion strengthening is not being exploited by the current generation of ODS superalloys at higher temperatures; crack initiation is found to occur prematurely due to the presence of recrystallization defects in the form of fine grains. The mechanism of crack initiation at fine grains is creep-type cavitation on boundaries transverse to the applied stress. Experimental results indicating the influence of temperature, loading frequency, and waveshape on the crack initiation rate are presented and discussed in detail. A qualitative correlation between waveshape and creep-fatigue life is suggested based on the macroscopic inelastic strain rate which is determined by the waveform and limits in turn the rate at which cavity growth can be accommodated.
Link zu diesem Datensatz: urn:nbn:de:bsz:291-scidok-20119
hdl:20.500.11880/24051
http://dx.doi.org/10.22028/D291-23995
SciDok-Publikation: 30-Jan-2009
Fakultät: Sonstige Einrichtungen
Fachrichtung: SE - INM Leibniz-Institut für Neue Materialien
Fakultät / Institution:INM
SE - Sonstige Einrichtungen

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