MADALINA STANCIULESCU, MARIOARA ABRUDEANU, CATALIN DUCU, ADRIANA GABRIELA PLAIASU CHEMICAL REDISTRIBUTION AND MICROSTRUCTURAL EVOLUTION OF ODS FE-CR POWDERS DURING MECHANICAL ALLOYING The oxide dispersion strengthened ferritic steel powders with chemical composition of Fe-14Cr-3W-0.3Y2O3 were mechanically alloyed from elemental powders in a planetary ball mill. Microstructural and chemical changes at different milling times were investigated by electron microscopy (SEM-EDS) and X-ray diffraction analysis (XRD). It was observed that morphology and structure of powders have experienced many stages during milling, and a quantitative mechanism was proposed. The initiation and evolution of the alloy formation started somewhere around 32 h of mechanical alloying (MA). According to microscopy and XRD analysis, in the first MA stages, milling chiefly has resulted in severe plastic deformation and grain refinement of powders, while in the later stages, alloying was progressed. It seems that 32 hours of milling are necessary to initiate the alloying process of Fe with Cr, but 78 h are not sufficient for completely dissolving W into á-Fe matrix retarding the Fe-Cr-W solid solution formation.