Fe-based oxide dispersion strengthened (ODS) powders were produced by high energy ball milling, fol- lowed by spark plasma sintering (SPS) for consolidation. The mixed powders of 84Fe-14Cr-2Y2O3 (wt%) were mechanically milled for 10 and 90 mins, and then consolidated at different temperatures (900~1100o C). Mechani- cally-Alloyed (MAed) particles were examined by means of cross-sectional images using scanning electron micros- copy (SEM). Both mechanical alloying and sintering behavior was investigated by X-ray diffraction (XRD) and high resolution transmission electron microscopy (HR-TEM). To confirm the thermal behavior of Y2O3, a replica method was applied after the SPS process. From the SEM observation, MAed powders milled for 10 min showed a lamella structure consisting of rich regions of Fe and Cr, while both regions were fully alloyed after 90 min. The results of sintering behavior clearly indicate that as the SPS temperature increased, micro-sized defects decreased and the den- sity of consolidated ODS alloys increased. TEM images revealed that precipitates smaller than 50 nm consisted of YCrO3.

The present work investigated the dispersion behavior of Y2O3 particles into AISI 316L SS manufactured using laser cladding technology. The starting particles were produced by high energy ball milling in 10 min for pre- alloying, which has a trapping effect and homogeneous dispersion of Y2O3 particles, followed by laser cladding using CO2 laser source. The phase and crystal structures of the cladded alloys were examined by XRD, and the cross section was characterized using SEM. The detailed microstructure was also studied through FE-TEM. The results clearly indi- cated that as the amount of Y2O3 increased, micro-sized defects consisted of coarse Y2O3 were increased. It was also revealed that homogeneously distributed spherical precipitates were amorphous silicon oxides containing yttrium. This study represents much to a new technology for the manufacture and maintenance of ODS alloys.