Investigation of precipitate in an austenitic ODS steel containing a carbon-rich process control agent

Highlights: • Yttrium stays in metallic state during mechanical alloying. • Process control agent has an influence on the formation of precipitates. • Titanium was found in two different phases after annealing. • Big CrTiCO clusters were found after annealing. • Small YTiO were observed in annealed powder. - Abstract: Austenitic oxide dispersion strengthened (ODS) steels are one of the candidates as a structural material for high-temperature applications in future power plants. To guarantee the necessary high production yield, the production process was improved in terms of reproducibility and scalability, by adding a process control agent (PCA) during the milling process. Due to this addition and the inherent change of the production process, the produced powder was thoroughly investigated using transmission electron microscopy and X-ray absorption spectroscopy methods to reveal the formation of chromium-rich carbides adjunct to titanium. Hence, less titanium was available to form the preferred complex nano-oxides the addition of carbon to the system influences the formation of precipitates severely in terms of their amount and size. The mechanical alloying process itself was unaffected by the addition of a PCA, and mixing and alloying of used elements still occurs.