Y2O3 Morphology in an Oxide Dispersion Strengthened FeAl Alloy Prepared by Mechanical Alloying

Abstract

ABSTRACTThe microstructure of an oxide dispersion strengthened FeAl (Zr,B) alloy, manufactured by mechanical alloying then extrusion, has been examined by HREM. Y2O3 is dispersed throughout the FeAl matrix as particles, ranging in size from 5nm upwards, which are effective in pinning the bulk dislocations. Although in the main the observed oxide particles are irregular in morphology, a significant minority of particles exhibit faceted surfaces. In particular, the facets of the Y2O3 particles are observed to coincide with {100}B2, {110}B2 and {112}B2 planes of the surrounding bulk FeAl matrix. In addition, HREM imaging reveals uncoupled 1/2<111>FeAl superpartial dislocations lying a few nanometres from some of the FeAl - Y2O3 interfaces.