Microstructural Evolution of an Oxide Dispersion Strengthened Steel Produced by Spark Plasma Sintering

The present work investigates the microstructural evolution of an oxide dispersion strengthened (ODS) steel alloy due to annealing. The ODS powder with composition (wt%): Fe – 19.7Cr – 0.4Y – 0.5Ti, was produced by a gas atomization process in an argon atmosphere containing 1000 ppm O2 and was further consolidated by spark plasma sintering (SPS). Samples were subjected to heat treatments at various temperatures in vacuum in order to obtain a microstructure similar to that found in commercially produced ODS alloys. Microstructural characterization was performed using an analytical transmission and scanning electron microscopy. A dispersion of nanometer-size oxide particles throughout the grain structure is observed suggesting an increased material resistance to creep