Mechanosynthesis of intermetallic Fe100-xAlx obtained by reduction of Al/Fe2O3 composite

AlxFe100-x alloy has been obtained through mechanical alloying of Al + Fe2O 3 under an argon atmosphere. The resulting phase has a composition dose to Al30Fe70 with disordered body-centred cubic structure and cell parameter a = 2.892(4) Angstrom. The magnetic properties studied by Mossbauer and magne tization measurements are consistent with an x similar to 30 composition. A nnealing at 983 K produces only minor changes in the magnetic properties. A possible mechanism for formation of AlxFe100-x is suggested, consisting of (a) initial grain downsizing to nanometric scale and (b) subsequent decompo sition of alpha -Fe2O3 producing metallic iron that is dissolved into the A l matrix. In contrast, no new phases were produced in a twin experiment on ball-milled Fe + Al2O3, carried out under identical milling conditions.