Investigation of the relationship between mechanical properties and microstructure in a Fe-9%Cr ODS steel
Abstract
Ferritic-martensitic Oxide Dispersion Strengthened (ODS) steels are potential
materials for fuel pin cladding in Sodium Fast Reactor (SFR) and their optimization is essential
for future industrial applications. In this paper, a feasibility study concerning the obtaining of
specimens into a quenched-dilatometer is presented. The ODS steel investigated contains 9%Cr
and exhibits a phase transformation between ferrite and austenite around 880°C. The purpose was
the generation of model microstructures and the evaluation of their tensile properties. The
specimens were machined from a cladding tube and underwent highly controlled heat treatments
into the dilatometer. Then, tensile tests were performed on the model microstructures. Thereafter,
macroscopic residual stresses relaxation during the heat treatment was evaluated.
Results show that a martensitic structure seems to be the most optimized state for the tensile
properties even if a reasonable fraction of ferrite does not appear to be compromising. Moreover,
macroscopic residual stresses within the tube linearly decrease upon increasing temperature. The
dilatometer has turned out to be an efficient method to perform analytic treatments and generate
microstructures. However, in this investigation, experimental phenomena such as decarburization
remain an important source of limitation and need to be controlled.
Origin : Files produced by the author(s)
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