Characterization and mechanical behavior of mechanically milled and hot extruded oxide dispersion strengthened steel

Mechanically milled and hot extruded Fe-9Cr-0.13C-2W-0.4Ti-0.35Y2O3 Oxide Dispersion Strengthened (ODS) steel rods were characterized in the present study. It was observed that material flow at the periphery is different from that at the center as observed from the flow lines in the alloy. Detailed characterization revealed ferrite, fine martensite, M23C6 and a dispersant phase rich in Y, Ti, O, which is distributed throughout the microstructure. X-Ray Diffractograms identified the dispersant phase to be Y2Ti2O7 phase. ODS steel shows hardness of 282.5 HV5 and impact toughness of 88.9 J at room temperature. Tensile properties were evaluated at both room temperature and 600 °C. These were compared with commercially available 9% Cr steel and it was observed that present ODS steel possesses higher tensile properties in comparison with reported data on wrought and commercially available 9% Cr steels. Overall, it can be concluded that mechanically milled and hot extruded Fe-9Cr-0.13C-2W-0.4i-0.35Y2O3 ODS alloy is a potential candidate for high temperature turbine blading applications.