Microstructure and Hardness Properties of Oxide Dispersion Strengthened Fe-18Cr Ferritic Steels Reinforced with Nano-Alumina

Oxide dispersion strengthening steel (ODS) is widely used in high-severity environments in supercritical water gasification (SCWG) due to its high-temperature corrosion resistance and fatigue strength. Nano-oxide can be used as reinforcement for ODS steel to enhance the mechanical properties by retarding dislocation at grain boundaries. This work aims to study the fabrication of Fe-18Cr ODS steels reinforced with 0.5-3.0 wt% nano-Al 2 O 3 contents. The microstructure of ODS steels before and after sintering processes was observed by an optical microscope, and the hardness test was conducted by a Micro-Vickers hardness tester. The results showed the mass gain increased by 49.18±10.75 mg cm -2 due to the formation of Fe 2 O 3 during the sintering process. The average porosity of ODS steels after sintering decreased by about 60% due to thermal contraction, resulting in their average densities increased by around 7 %. Moreover, the hardness of Fe-18Cr ODS steels increased up to 120 HV with the increase in nano-Al 2 O 3 percentage.