Oxidation behavior and high-temperature tensile properties of Fe-9Cr-(Mo, Mo/Ni) alloys

Abstract Fe-9Cr, Fe-9Cr-1Mo and Fe-9Cr-0.5Mo-0.5Ni (wt%) alloys have been prepared for studying the effect of (Mo, Mo/Ni) on carbide precipitation, oxidation behavior and high-temperature tensile property of Fe-9Cr alloy. Rod-shaped Cr23C6 precipitates in Fe-9Cr alloy were refined and spheroidized by Mo addition, while Mo/Ni addition had no impact on Cr23C6 precipitates. Adding (Mo, Mo/Ni) to Fe-9Cr alloy reduced inward oxygen diffusion and the growth rate of an inner Cr-rich layer, thereby accelerating chromia formation and improving the oxidation resistance. High-temperature strength of Fe-9Cr alloy was also enhanced by alloying elements (Mo, Mo/Ni).