Phase transformations in nanocrystalline mechanically alloyed Ni-Mo powders

The mechanical alloying process of Ni-20 at.% Mo powder mixture led to the formation of fcc Ni(Mo) solid solution, characterized by lattice parameter of 0.3612 nm, crystallite size 30 nm and lattice strain 0.8% The synthesis in argon of Ni-43 at.% Mo alloy, both under high and low energy conditions, resulted in the formation of two-phase structure. amorphous + nanocrystalline Mo. The presence of oxygen during milling in air and with addition of ethanol, reduced the structure refinement and formation of Ni(Mo) solid solution. Moreover, the amorphous structure was not observed in this case. (C) 1999 Acta Metallurgica Inc.