Investigation on different oxides as candidates for nano-sized ODS particles in reduced-activation ferritic (RAF) steels

Abstract

Future generation reactor concepts are based on materials that can stand higher temperatures and higher neutron doses in corrosive environments. Oxide dispersion strengthened steels with chromium contents ranging from 9 to 14wt.% – produced by mechanical alloying – are typical candidate materials for future structural materials in fission and fusion power plants.Y2O3 has proven to be a good candidate for addition to ferritic steels during mechanical alloying to form nano-sized dispersion oxide particles during compacting of the material. These oxide particles have many positive effects on the material such as improved high-temperature properties and higher corrosion resistance. However, there is potential for improvements by choosing different oxides.In this present work, four different oxides (MgO, La2O3, Ce2O3 and ZrO2) are selected by looking at their thermal stabilities and Gibbs free enthalpies of various chemical compositions. These oxides are mixed and mechanically alloyed with ferritic steel powder (Fe13Cr1W0.3Ti) and compared to a reference material produced with Y2O3 (Fe13Cr1W0.3Ti+Y2O3). The materials were characterized in terms of their mechanical properties and detailed microstructural investigations by transmission electron microscopy and electron backscatter diffraction.All further results of the mechanical testing and microstructural characterizations are analyzed, compared, and discussed in this paper.