Abstract
The T91-oxide dispersion strengthening alloys were fabricated by directly adding Y2O3 at the micrometer scale using a casting method. The microstructural observation and energy dispersive spectral analysis revealed that complex oxide particles with diameters of 2–5 mm, which contained elemental Y, were produced because of the chemical reactions between the added Y2O3 particles and the matrix elements. Fractures appeared after tensile testing, and a substrate beneath the complex oxide particles was formed to generate equiaxial dimples centered on the oxide particles. Moreover, the mechanical properties of the T91-oxide dispersion strengthening steel containing 0·2% (wt-%) Y2O3 were superior to the T91-oxide dispersion strengthening containing 0·4% Y2O3, and differed greatly from that of common T91 steel.