ISSN 1061-3862, International Journal of Self-Propagating High-Temperature Synthesis, 2009, Vol. 18, No. 2, pp. 125–132. © Allerton Press, Inc., 2009. 125 INTRODUCTION As is known [1–3], the size of SHS-produced grains/crystallites can be minimized in one of the fol- lowing two ways. One is the use of fine starting pow- ders or the reagents that undergo atomization within the combustion wave while the second is optimization of cooling conditions to suppress the growth of product particles. In practice, this is achieved by using (a) dif- ferent methods of preliminary activation, (b) reduced combustion temperatures, (c) accelerated cooling of reaction products, (d) isolation of product particles with gaseous of solid byproduct/diluent, etc. The advantages of mechanically activated SHS (MASHS) as a method for synthesis of nanomaterials have been demonstrated in [4–8]. the mechanocompos- ites formed at the stage of mechanoactivation (MA) were found to decrease the combustion temperature and increase the burning velocity [9–25], thus enabling the formation of nanostructured products. MASHS was successfully used to produce nanocrystalline FeAl [11, 13, 15], NbAl 3 [12], MoSi 2 [18, 26], TiC [24], Mg 2 Ni [27], Ni 3 Al, NiTi [7, 28] and also composite TiB 2 –Cu, TiB 2 –TiNi, TiB 2 –TiAl 3 , and TiB 2 –TiB–Ni 3 Al nanopo- wders [29, 30]. SHS reaction initiated in mechanoacti- vated (2 + x)Al + 3NiO mixtures below the melting point of reagents was found to yield a product disper- sion-strengthened with ultrafine inclusions of Al 3 Ni and Al 2 O 3 [31]. Meanwhile, some aspects of MA as per fabrication of nanostructured SHS products still remain unclear. For instance, it was suggested [13] to conduct MA of Fe–Al mixtures in order to prepare laminated Fe–Al nanolayers without marked chemical interaction between the reagents. In this case, formation of unde- sirable by-products during MA could be avoided by regulating the amount of energy stored during MA. At the same time, it is believed [6] that the formation of some amount of resultant product during MA may have a positive effect: these particles will act as crystalliza- tion seeds during subsequent SHS process, along with some decrease in combustion temperature. The data of modeling for the reaction of Nb with C have shown that some amount of such centers can be expected to dimin- ish the size of product grains and accelerate combus- tion. According to [32–34], the use of nanocomposites formed during MA as precursors of SHS results in for- mation of intermetallide/oxide nanocomposites that retain the morphology of precursor particles. In this work, we explored the MASHS of composite nanopowders in Fe + Al + Fe 2 O 3 and Fe + Al + Cr 2 O 3 mixtures. EXPERIMENTAL In experiments aimed at preparation of Fe–40 at % Al intermetallide, we used the following two green mixtures: 60.9 wt % Fe + 26.6 wt % Al + 12.5 wt % Fe 2 O 3 (mix 1) 65.9 wt % Fe + 26 wt % Al + 8.1 wt % Cr 2 O 3 (mix 2). Respective overall reaction schemes can be repre- sented in the form: Fe + Al + Fe 2 O 3 FeAl + Al 2 O 3 , (1) Fe + Al + Cr 2 O 3 FeAl(Cr) + Al 2 O 3 . (2) The blends were mechanoactivated in an AGO-2 planetary ball mill (250 cm 3 , ball diameter 5 mm, balls weight 200 g, sample weight 10 g, 1000 rpm, under Ar) [32]. After MA, the blends were compacted (under a load of 4–6 t) into pellets 17 mm in diameter and about 25 mm high. Combustion under Ar was initiated with an electrically heated tungsten coil [33]. Combustion Mechanoactivated SHS of FeAl-Based Nanocomposite Powders T. L. Talako a , T. F. Grigor’eva a , A. I. Letsko a , A. P. Barinova a , P. A. Vitiaz a , and N. Z. Lyakhov b a Powder Metallurgy Institute, ul. Platonova 41, Minsk, 220005 Belarus b Institute of Solid State Chemistry and Mechanochemistry, ul. Kutateladze 18, Novosibirsk, 630128 Russia e-mail: talako@tut.by Received March 9, 2009 Abstract—FeAl-based nanocomposite powders were prepared by mechanically activated SHS (MASHS) using Fe + Al + Fe 2 O 3 and Fe + Al + Cr 2 O 3 powder mixtures as starting materials. In both the cases, the syn- thesized powders were found to inherit the structural morphology of mechanocomposites (precursors) formed in the course of mechanical activation. Key words: mechanoactivated SHS (MASHS), composite nanopowders, iron monoaluminide DOI: 10.3103/S1061386209020101