Morphology and structure evolution of Y2O3 nanoparticles in ODS steel powders during mechanical alloying and annealing

(a) Morphology and (b) HRTEM images of Y2O3 after MA for 5 h. Y2O3 nanoparticles changed into flake polygons and rods from the nearly spherical shape after mechanical alloying (MA). The lattice structure of Y2O3 was damaged at the initial stage of MA, and amorphous areas appeared during this process.160