Bulk FeAl nanostructured materials obtained by spray forming and spark plasma sintering

This paper examines the efficiency of two consolidation processing techniques high velocity oxy-fuel (HVOF) spray forming and spark plasma sintering (SPS) which allow to obtain bulk dense nanostructured materials. An oxide dispersion strengthened (ODS) Fe–40Al (at.%) based milled powder (with a nanostructure < 30 nm in size) was used as a precursor. The microstructures of the sintered end-products were characterized by transmission electron microscopy (TEM). The results indicated that, under the present processing conditions, the HVOF spray forming is more effective to retain nanograins (30–90 nm in size) within unmelted powder particles. However, the SPS processing shows its potential to fully densify the material while retaining ultrafine grains having sizes in the range 100–400 nm together with larger micrometer grains.