Cyclic instability of martensite laths in reduced activation ferritic/martensitic steels

WITHDRAWN: Dislocation-based constitutive modeling of martensitic/ferritic steels at elevated temperatures. Part II: Cyclic behavior without hold time effects

“…Transmission electron microscopic (TEM) analyses have enabled researchers to attribute lath/subgrain coarsening in the martensitic/ferritic microstructure as the primary reason for cyclic softening in this class of steels (Chilukuru et al, 2009;Dubey et al, 2005;Fournier et al, 2006). The degree of microstructural coarsening has been shown to correlate with the applied inelastic strain per cycle (Fournier et al, 2009a) and is enabled by annihilation of dislocations introduced during martensitic transformation (Armas et al, 2004), coarsening of precipitates (Jones, 1983;Kim and Weertman, 1988) and changes in effective applied stress due to surface oxide film formation (Ebi and McEvily, 1984). Analysis of the stress-strain hysteresis loops has revealed that this cyclic softening effect is primarily due to a gradual decrease in the long-range internal stresses or backstresses (Fournier et al, 2006).…”

Low cycle fatigue of Eurofer 97

“…Up to now, published data on the fatigue properties of Eurofer 97 and the corresponding microstructures are scarce (see for instance Refs. [1,2]). The first part of the work is an investigation of the room temperature low cycle fatigue properties, under air.…”

In situ fatigue of the Eurofer 97 steel

“…Nevertheless, the increased stress level found in the in-beam specimens is not a direct indication of irradiation hardening. To assess the irradiation hardening, the curves have been compared as in a previous study [9] for Eurofer 97, on a log-log scale, to the curves of specimens tested at T def (see Fig. 2).…”