Nano-scale oxide dispersoids by internal oxidation of Fe-Ti-Y intermetallics

摘要

The processing of high-temperature alloys containing nano-scale oxide dispersoids usually involves mechanical alloying, but dispersoid formation by internal oxidation is also an option. In this work, the internal oxidation of the intermetallics Fe_(17)Y_2 and Fe_(11)YTi was studied. Internal oxidation resulted in small (～20nm) oxide particles in an iron solid solution matrix. Oxides such as Y_2O_3, YFeO_3, Y_2Ti_2O_7, and Fe_2TiO_4 were observed. Hardness values as high as those of the original intermetallics were observed. However, the oxide particles coarsened quickly during annealing at 1000 ℃. In order to reduce the coarsening rates, oxides more similar to those in mechanically alloyed steels need to be synthesized.