The microstructure characterization of reduced activation F82H-ODS ferritic steel

For the reduced activation F82H-ODS ferritic steel developed as the advanced fusion blanket material, the structure control and phase formation mechanisms were investigated. The area fraction of the ferrite phase was reduced, when the specimens were annealed at 1250 °C for long enough time inducing oxide particle coarsening. The effect of oxide particles on α-γ transformation was investigated, and ferrite formation is ascribed to pinning of α-γ interfacial boundaries by the dispersed oxide particles. This ferrite is meta-stable, and designated as residual-ferrite.