Chemical and structural evolution of nano-oxides from mechanical alloying to consolidated ferritic oxide dispersion strengthened steel

Ferritic Oxides Dispersion Strengthened (ODS) steels are of great interest for nuclear fission and fusion power plants. The nano-oxides embedded into the matrix provide main contribution to ODS steel strength. Understanding precipitation mechanism is thus critical optimizing fabrication process, involving Mechanical Alloying (MA) Fe-14Cr, Y2O3 TiH2 powders. In this study, results from small-angle X-ray neutron scattering, atom probe tomography electron microscopy have been combined investigate evolution throughout whole consolidation thermal treatment until 1100 °C. After MA clusters observed, composed Y, O Ti. During heating these grow new ones nucleate, together with a sequential enrichment in Ti (from as-MA 700 °C) Y (between 900 °C). A small quantity Al also found between At °C be mainly Y2Ti2O7 subsequently progressively transform Y2TiO5 during isothermal holding. Nano-oxides display however an unchanged extremely low coarsening rate, demonstrating outstanding stability both at