Studies on alloying process of a ferritic/martensitic oxide dispersion strengthened (ODS) steel prepared by mechanical alloying of elemental powders

Ferritic/martensitic oxide dispersion strengthened steel with a nominal composition of Fe-9Cr-2W-0.2Ti-0.12C-0.35Y(2)O(3) was produced by mechanical alloying in a high energy horizontal Simoloyer attritor. Powder samples were collected at intervals of 0.5, 1, 2, 3, 5, 7 and 10h and analysed by X-ray diffraction, scanning electron microscopy, energy-dispersive spectroscopy, transmission electron microscopy and differential thermal analysis. The alloying elements (Cr and W) got dissolved in the matrix in 7h milled powder. Crystallite size decreased rapidly with milling time up to 5h milling and reached a stable size of similar to 12 nm after 7h, whereas strain and lattice parameter were found to increase with milling time. The particle size increased up to 2h milling and then decreased with milling time. A fine and uniform particle size of similar to 25 nm was obtained after 7h milling. The alloying process and distribution of alloying elements/Y2O3 is studied in the present work.