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

摘要

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. percent) 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.