FeAl-B composites with nanocrystalline matrix produced by consolidation of mechanically alloyed powders

Mechanically alloyed composite powders with equiatomic Fe-Al stoichiometry and with the addition of 5, 10, 20 and 30 vol% of B were subjected to consolidation. For this purpose, hot-pressing at 800 degrees C under the pressure of 7.7 GPa for 180 s was applied. A reference FeAl sample was prepared using the same procedure as these from the composite powders. The produced bulk materials were investigated by X-ray diffraction, scanning electron microscopy and energy dispersive X-ray spectroscopy as well as characterised by hardness, density and open porosity measurements. For the compositions containing 5, 10 and 20% of B, it was possible to obtain composites with the nanocrystalline FeAl intermetallic matrix reinforced with homogenously distributed fine boron particles. For the material containing 30% of B, the boron particles were distributed in a two-phase matrix consisting of the dominant nanocrystalline FeAl intermetallic and minor amorphous phases. The density of the composite samples is in the range of 5.31 divided by 4.57 g/cm(3), which is lower than that of the FeAl reference sample, and decreases with the increase of B content. The hardness of the composite samples is in the range of 10.75 divided by 12.1 GPa, is higher than that of the intermetallic FeAl reference sample (9.84 GPa), and increases with the increase of B content. To the best of our knowledge, the FeAl-B composites with nanocrystalline intermetallic matrix were produced for the first time. (C) 2019 Elsevier B.V. All rights reserved.