Microstructural evolution during high temperature dwell-fatigue of austenitic stainless steels. (February 2021)

• Record Type: Journal Article
• Authors: Wärner, Hugo; Xu, Jinghao; Chai, Guocai; Moverare, Johan; Calmunger, Mattias
• Is Part Of: International journal of fatigue. Volume 143(2021)
• Publication Date: 2021-02
• Subjects: Creep-fatigue interaction -- High temperature austenitic alloys -- High-resolution microscopy -- Dynamic recrystallization of crack tip plastic zone; Materials -- Fatigue -- Periodicals; Materials -- Fatigue; Periodicals; 620.1122
• DOI: 10.1016/j.ijfatigue.2020.105990
• Languages: English
• ISSNs: 0142-1123

Abstract

Highlights: Creep-fatigue interaction behaviour at 700 °C for Sanicro 25 and Esshete 1250. Microstructural evolution and dynamic recrystallization of crack tip plastic zone. High resolution imaging of dispersed precipitates interaction with dislocations. Abstract: Microstructural evolution related to the mechanical response from isothermal dwell-fatigue testing at 700 °C of two austenitic steels, Esshete 1250 and Sanicro 25, is reported. Coherent Cu-precipitates and incoherent Nb-carbides were found to impede dislocation motion, increase hardening and improving the high temperature properties of Sanicro 25. Sparsely placed intergranular Cr- and Nb-carbides made Esshete 1250 susceptible to creep damage and intergranular crack propagation, mainly from interaction of the carbides and fatigue induced slip bands. Dynamic recrystallization of the plastic zone at the crack tip appeared to affect crack propagation of Sanicro 25 by providing an energetically privileged path.