The mixture of the Ni, Fe and Mo elemental powders with the nominal composition of the Supermalloy was milled in a planetary mill under Ar atmosphere. Several milling times have been used ranging from 4 to 16 h. A heat treatment of 30 min, 1, 2 and 4 h at temperature of 350degreesC has been performed in vacuum in order to improve the alloying process and remove the internal stresses. The formation of the Fe-Ni-Mo alloys by mechanical alloying was evidenced by X-ray diffraction. The nanocrystalline Supermalloy powders have been obtained after 16 h milling and after 8 h milling followed by 4 h annealing. A typical grain size of 11 +/- 2 nm have been obtained after 16 h milling. The chemical homogeneity composition and the morphology of the powder particles have been studied by X-ray microanalysis and scanning electron microscopy respectively. (C) 2004 Kluwer Academic Publishers.