Isothermal grain growth studies on nanostructured 9Cr-1Mo and 9Cr-1W ferritic steels containing nano-sized oxide dispersoids

Analysis of isothermal grain growth kinetics of nanocrystalline Fe-9Cr-1Mo and Fe-9Cr-1W-based ferritic oxide dispersion strengthened alloys is reported. Fe-9Cr-1Mo-0.25Ti-0.5Y2O3 alloy exhibited ∼900 and ∼250 pct enhancement in grain-coarsening resistance at 1073 K (800 °C) in comparison with Fe-9Cr-1Mo-0.5Y2O3 alloy and Fe-9Cr-1W-0.5Y2O3 alloy, respectively. Comparison of grain growth time exponents also revealed that addition of Ti and Y2O 3 to nanocrystalline Fe-9Cr alloy has significantly enhanced the grain growth resistance. This is attributed to the possible presence of Y-Ti-O-based nanoclusters (<5 nm). © 2014 The Minerals, Metals & Materials Society and ASM International.