Development of porosity in an oxide dispersion-strengthened ferritic alloy containing nanoscale oxide particles

The development of porosity at 1000 °C in an oxide dispersion-strengthened ferritic alloy containing nanoscale (∼2–4 nm) oxide particles is investigated. A comparison with an alloy fabricated by internal oxidation instead of mechanical alloying demonstrates that the porosity formation is associated with mechanical alloying of the alloy powder with Y2O3 in argon. The pores grow in spite of a submicron grain size suggesting that the grain boundaries are not effective paths for removing entrapped gas from the pores.