Ferrtic/martensitic and ODS steels were fabricated by the mechanical alloying process, and their microstructures and mechanical properties were investigated. The 9Cr-1W and 9Cr-1W-0.3Ti-0.35Y2O3 (in wt.%) steels were prepared by the same fabrication process such as mechanical alloying, hot isostatic pressing, and hot rolling processes. A microstructural observation of these steels indicated that the Ti and Y2O3 additions to 9Cr-1W steel were significantly effective to refine the grain size and form nano-sized Y-Ti-O oxide particles. As a result, the tensile strengths at room and elevated temperatures were considerably enhanced. Considerable improvement of the creep resistances at 700°C was also evaluated. It is thus concluded that 9Cr-1W ODS steel with Ti and Y2O3 additions would be very effective in improving the mechanical properties especially at elevated temperatures.

Ni-16Mo and ODS alloys were fabricated by the powder metallurgical processes, and their microstructures and tensile properties were investigated. Ni-16Mo-7Cr and Ni-16Mo-7Cr-0.3Ti-0.35Y₂O₃ (in wt.%) alloys were prepared by mechanical alloying, uniaxial hot pressing, and heat treatment processes. Microstructural observations of these alloys revealed that the Ti and Y₂O₃ additions to a Ni-16Mo alloy were significantly effective to refine the grain size and form nano-sized Y-Ti-O oxide particles. Consequently, the tensile strengths at room temperature and 700°C were considerably enhanced. This improvement of tensile properties can be mainly attributed to the formation of nano-sized oxide particles, as well as the refined grain size. It is thus concluded that Ni-16Mo alloy with Ti and Y₂O₃ additions would be very effective in improving the mechanical properties especially at elevated temperatures.