Influence of the milling conditions on the microstructure and mechanical properties of Oxide Dispersion Strengthened Steels
Résumé
Oxide dispersion strengthened (ODS) steels are promising materials as fuel claddings for future nuclear reactors. Indeed, they exhibit a good swelling resistance under irradiation thanks to their metallic body-centered cubic matrix FeCrW [1]. Beside, their titanium and yttrium nano-oxides dispersion increases their mechanical properties at high temperature [2] and under irradiation [1]. The usual way to produce an ODS material is a high energy milling of powders FeCrWTi and Y2O3 followed by thermo-mechanical treatments. Nevertheless, the process seems to be rather hard to control since the huge variations of mechanical properties observed in the literature.Previously, a new elaboration route inspired of reactive ball milling was developed on a very small milling device (FeCrW+YFe3+Fe2Ti+Fe2O3) where the crucial role of the milling parameters was highlighted [3, 4]. Two powders revealed different after milling remained different despite any post-milling heat treatment [4]. The goal of the actual study is to elaborate hot extruded ODS steels with the new method and determine the influence of milling parameters on the microstructure and the mechanical properties. This study proves the efficiency of the new procedure at large scale to elaborate ODS steels and highlights the role of carbon and nitrogen on the mechanical properties.[1]R.L. Klueh et al., Journal of Nuclear Materials. 341 (2005) 103.[2]T.R. Allen et al., Journal of Nuclear Materials. 375 (2008) 26.[3]M. Brocq et al. , Journal of Nuclear Materials. 409 (2011) 80.[4]M. Laurent-Brocq et al., Acta Mater. 60 (2012) 7150.