MICROSTRUCTURES AND TENSILE PROPERTIES OF Fe-Cr-Al OXIDE DISPERSION STRENGTHENED FERRITIC ALLOYS FOR HIGH TEMPERATURE SERVICE COMPONENTS

In present study, Fe-22Cr-4.5Al oxide dispersion strengthened ferritic alloys were fabricated using a pre-alloyed powder with different minor alloying elements, and their microstructures and tensile properties were investigated to develop the advanced structural materials for high temperature service components. Planetary-typed mechanical alloying and uniaxial hot pressing processes were employed to fabricate the Fe-Cr-Al oxide dispersion strengthened ferritic alloys. Microstructural observation revealed that oxide dispersion strengthened ferritic alloys with Ti, Zr additions presented extremely fine micro-grains with a high number density of nano-scaled oxide particles which uniformly distributed in micro-grains and on the grain boundaries. These oxide particles were confirmed as a fine complex oxide, Y2Zr2O7. These favorable microstructures led to superior tensile properties than commercial ferritic stainless steel and oxide dispersion strengthened ferritic alloy with only Ti addition at elevated temperature.