Název: Crack initiation in austenitic stainless steel sanicro 25 subjected to thermomechanical fatigue
Autoři: Petráš, Roman ; Škorík, Viktor ; Polák, Jaroslav
Typ dokumentu: Příspěvky z konference
Konference/Akce: MSMF8. International Conference on Materials Structure and Micromechanics of Fracture /8./, Brno (CZ), 20160627
Rok: 2017
Jazyk: eng
Abstrakt: Thermomechanical fatigue experiments were performed with austenitic stainless Sanicro 25 steel. Several amplitudes of mechanical strain in a wide temperature interval (250-700 °C) were applied to the specimens. Mechanical response was recorded and fatigue lives were obtained. Scanning electron microscopy combined with FIB technique was used to study the mechanism of crack initiation in in-phase and in out-of-phase thermomechanical cycling. Different mechanisms of the crack initiation were found in these two types of loading. During in-phase loading fatigue cracks start in grain boundaries by cracking of the oxide. Cracks grew preferentially along grain boundaries which resulted in rapid crack initiation and low fatigue life. In out-of-phase loading multiple cracks perpendicular to the stress axis developed only after sufficiently thick oxide layer was formed and cracked in low temperature loading half-cycle. The cracks in oxide allowed localized repeated oxidation and finally also cracking. The cracks grow transgranularly and result in longer fatigue life.
Klíčová slova: Damage mechanism; FIB cutting; Localized oxidation-cracking; Sanicro 25 steel; Thermomechanical fatigue
Číslo projektu: LQ1601 (CEP), GA13-23652S (CEP), LM2015069 (CEP)
Poskytovatel projektu: GA MŠk, GA ČR, GA MŠk
Zdrojový dokument: Materials Structure & Micromechanics of Fracture VIII, ISBN 978-3-03835-626-4, ISSN 1662-9779

Instituce: Ústav fyziky materiálů AV ČR (web)
Informace o dostupnosti dokumentu: Dokument je dostupný v příslušném ústavu Akademie věd ČR.
Původní záznam: http://hdl.handle.net/11104/0277273

Trvalý odkaz NUŠL: http://www.nusl.cz/ntk/nusl-373285


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