Enhancement of tensile properties due to microstructure optimization in ODS steels by zirconium addition

The effect of zirconium (Zr) addition on the microstructure and tensile properties of aluminum (Al) added ferritic ODS steel Fe-16Cr-3Al-1.5W-0.35Y2O3 (16Cr3Al ODS) was investigated. Experimental analysis indicated that the addition of Zr refined oxide particles by forming finer Y-Zr-O particles instead of Y-Al-O particles encouraged grain refinement obviously from the results of TEM. The mean size of oxide particles decreased from 9.8 ± 1.7 nm to 8.0 ± 0.9 nm and the mean inter-particle distance decreased from 14.6 ± 1.5 nm to 10.5 ± 0.7 nm when Zr was added. In addition, the 16Cr3Al ODS steel containing Zr showed preferable yield strength and ultimate tensile strength compared with the ODS steel without Zr at several test temperatures, indicating the enhancement of tensile properties by the addition of Zr due to the optimization of microstructure in ODS steel by Zr addition.