One-step synthesis and consolidation of nanophase iron aluminide

The simultaneous synthesis and densification of nanophase iron aluminide is investigated. Elemental nanophase reactants produced by mechanical activation were reacted by field activation with the simultaneous application of uniaxial pressure. The process was demonstrated in this work by the synthesis of dense nanometric FeAl. Iron and aluminum powders were co-milled in a specially designed planetary mill to obtain nanometric reactants and to avoid formation of any product phases. These powders were then subjected to high AC currents (1250-1500 A) and pressures in the range of 70-106 MPa. Under these conditions, a reaction was initiated and completed within a short period of time (2.5-3.5 min). XRD and energy dispersive analyses showed the product to be Fe0.515Al0.485. The relative density of the product ranged from 98.7% to 99.7 %. The crystallite size of the "FeAl" intermetallic was determined by XRD line-broadening analysis using the Williamson-Hall method. The size ranged from 32 to 89 mn and showed a dependence on lattice direction.