Effect of powder preparation parameters on the oxide dispersion strengthening of ferritic steels

Oxide dispersion strengthened ferritic steels Fe-13Cr-2Mo-1W with different oxide additions, especially TiO₂, have been prepared by mechanical mixing of pure metal powders with oxides, isostatic compaction, sintering and swaging. The effects of the powder preparation history, the oxide content and the original oxide particle dimensions, on the mechanical properties at 700° C have been studied. It turns out that a first strengthening effect is due to the “presence” of oxides. This effect is increased by optimization of mixing and milling scheme of the powders, which improves the “distribution” of the oxide. An additional beneficial effect is obtained by decreasing the original oxide powder dimensions.