Abstract
The ductile-to-brittle transition (DBT) behavior of two similar Fe-Cr-Al oxide dispersion strengthened (ODS) stainless steels was analyzed following the Cottrell–Petch model. Both alloys were manufactured by mechanical alloying (MA) but by different forming routes. One was manufactured as hot rolled tube, and the other in the form of hot extruded bar. The two hot forming routes considered do not significantly influence the microstructure, but cause differences in the texture and the distribution of oxide particles. These have little influence on tensile properties; however, the DBT temperature and the upper shelf energy (USE) are significantly affected because of delamination orientation with regard to the notch plane. Whereas in hot rolled material the delaminations are parallel to the rolling surface, in the hot extruded material, they are randomly oriented because the material is transversally isotropic.
Highlights
Oxide dispersion strengthened (ODS) ferritic stainless steels are considered to be the most promising structural materials for several types of nuclear reactors, including future fusion reactors, because they combine an acceptable creep rupture strength, excellent swelling resistance, and high corrosion resistance in supercritical pressurized water [1,2,3,4]
PM2000 alloy—in which the fracture advances in the “crack divider” mode—the delaminations cause a decrease in both the ductile-to-brittle transition temperature (DBTT) and upper shelf (USE) with respect to those of monolithic material [15]
For LS-notched specimens—in which the fracture advances in the “crack arrester” mode—the delaminations cause a decrease in the DBTT and an increase in the USE, a convergence of the USE was noted at high temperatures [15]
Summary
Oxide dispersion strengthened (ODS) ferritic stainless steels are considered to be the most promising structural materials for several types of nuclear reactors, including future fusion reactors, because they combine an acceptable creep rupture strength, excellent swelling resistance, and high corrosion resistance in supercritical pressurized water [1,2,3,4]. These materials are usually produced by the mechanical alloying (MA) of yttria nano-particles and elementary powders of Fe, Cr, Al, and Ti elements [5]. This work compares and analyzes the ductile-to-brittle transition (DBT) behavior of two commercial ODS ferritic stainless steels of similar composition manufactured by two different MA routes, including hot extrusion and hot rolling
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
