Effects of MA environment on the mechanical and microstructural properties of ODS ferritic steels

The mechanical and microstructural properties of ODS ferritic steels mechanically alloyed (MA) in different atmospheres were investigated. Milling in the presence of nitrogen gas significantly reduced the particle size of the Fe–15.5Cr–2W–4Al–1Zr–0.35Y2O3 powder. After solidification of the MA powder, no bubble formation was found in the matrix of the steel mechanically alloyed in hydrogen atmosphere. A slight deterioration in the impact properties was attributed to the formation of large Zr(C,N) precipitates, as observed both in grains and on grain boundaries by TEM.