Publikationsrepositorium - Helmholtz-Zentrum Dresden-Rossendorf

Ferritic Fe14Cr based oxide dispersion strengthened (ODS) alloys are promising candidates for components of GEN IV reactors. Due to their high Cr content high corrosion resistance is provided and the austenite phase transformation is prevented. Matrix compositions containing Ti in combination with yttria as reinforcing constituent tend to the formation of complex Y-Ti oxides that are known for their small particle sizes. High creep resistance and yield strength as well as an improved resistance against radiation induced He embrittlement are expected improvements to be achieved by ODS.
The considered fabrication process consists of a mechanical alloying step and the subsequent consolidation. During these steps an evolution of the added yttria particles (≈30 nm) towards much smaller Ti-Y-O nanoclusters (2-5 nm) has been observed [ ; ]. However, the mechanisms of dissolution and especially the re-precipitation during the consolidation process are not well known yet.
In order to evaluate the influence of the processing parameters, powders of different compositions (0….0.6wt% Y2O3) are fabricated applying different milling times (20h; 30h). These powders are consolidated via spark plasma sintering (SPS). The sintered material has been characterized with respect to porosity, microstructure, spatial distribution of composition and Vickers hardness. Ongoing research is focussed on the characterization of the oxide particles at the nanometre scale.