The Influence of Powder Milling on Properties of SPS Compacted FeAl

The Fe-28 at.% Al alloy was studied in this article. The aim was to describe the influence of gas atomized powder pre-milling before SPS (Spark Plasma Sintering) sintering on the structure and properties of the bulk materials. The initial powder was milled for 0.5, 1, and 8 h. It was proven that 1 h milling leads to the change in size and morphology of the particles, B2→A2 phase transformation, and to the contamination with the material from a milling vessel. Powder materials were compacted by the SPS process at 900, 1000, and 1100 °C. The differences between the bulk materials were tested by LM, SEM, and TEM microscopy, XRD, and neutron diffraction methods. It was proven that, although the structures of initial powder (B2) and milled powder (A2) were different, both provide after-sintering material with the same structure (D0(3)) with similar structural parameters. Higher hardness and improved ductility of the material sintered from the milled powder are likely caused by the change in chemical composition during the milling process.