Oxide dispersion strengthened (ODS) steels are a class of advanced structural materials with a potential to be used at elevated temperatures. By introducing nano-scale oxide particles, the high temperature mechanical properties of ODS steels can be significantly improved compared to non-ODS counterparts. Although the application of the powder metallurgy route for ODS steels is well documented, this method is considered as a complex and costly fabrication technique. In the current project the feasibility of casting technology and subsequent internal oxidation, as an alternative method for the production of ODS steels, is under evaluation.
The internal oxidation of as-cast steels (Fe-16Cr-0.2Al and Fe-9Cr-0.2Al in wt.%) with presence of metal/oxide powder mixture, e.g. “Fe / FeO” and “V / VO” at 1000 °C inside quartz tube was investigated. The results with “Fe / FeO” buffer revealed the external oxidation of both alloys. In the experiments with “V / VO” buffer a single zone of internal oxidation was formed by the precipitation of discrete Al2O3 particles in an area beneath the surface. Further oxidation experiments with “V / VO” and “Cr / Cr2O3” buffers at 1300 °C inside alumina crucibles showed an enhanced depth of internally oxidized zone. The results from thermodynamic modelling are in a very good agreement with observations in the experiments. The obtained results are a promising step towards an alternative route of production for ODS steels.