Processing dense hetero-nanostructured metallic materials by spark plasma sintering

Fully dense hetero-nanostructured (i.e. containing intermixed nano and micrometric grains) metallic (FeAl) materials can be successfully produced by spark plasma sintering (SPS) when mechanically milled nanostructured powders are used. This is due to the large temperature differences generated during the SPS runs, which modify locally the recrystallization response of the heavily deformed structure during sintering. Y2O3 addition delays the onset of recrystallization and, thereby, produces microstructures containing more than 80% of sub-500 nm grains.