Isothermal Grain Growth Studies on Nanostructured 9Cr-1Mo and 9Cr-1W Ferritic Steels Containing Nano-sized Oxide Dispersoids

摘要

Analysis of isothermal grain growth kinetics of nano-crystalline Fe-9Cr-1Mo and Fe-9Cr-1W-based ferritic oxide dispersion strengthened alloys is reported. Fe-9Cr-1Mo-0.25Ti-0.5Y_2O_3 alloy exhibited ~900 and ~250 pct enhancement in grain-coarsening resistance at 1073 K (800 ℃) in comparison with Fe-9Cr-1Mo-0.5Y_2O_3 alloy and Fe-9Cr-1W-0.5Y_2O_3 alloy, respectively. Comparison of grain growth time exponents also revealed that addition of Ti and Y_2O_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).