Size and structure evolution of yttria in ODS ferritic alloy powder during mechanical milling and subsequent annealing

► Y2O3 still remains in the milled powders. ► The combination between yttrium atoms and oxygen atoms isn't fractured by MM. ► Y2O3 exists in nanocrystalline after MM. ► Growth of nanocrystalline Y2O3 has occurred during subsequent annealing.