Structural comparison of M–W (M = Fe, Ni) alloys produced by electrodeposition and mechanical alloying

Ductile amorphous and nanocrystalline M–W (M = Fe, Ni) alloys were produced by electrodeposition. The structural studies of these alloys were carried out by using extended X-ray absorption fine structure (EXAFS) and small angle X-ray scattering (SAXS) methods. The crystal structure of the electrodeposited Ni–W alloy was similar to that of Ni4W phase. The nearest Ni–Ni distance was determined to be 2.49 Å, Ni–W distance was determined to be 2.50 Å. The average crystal-grain size of the as electrodeposited Ni–W alloy was estimated to be about 2.5 nm from Guinier plot of SAXS spectra. The electrodeposited Fe-21.6 at.% W alloy has short range order, but not any medium range order around Fe and W atoms, it possesses amorphous structure. The nearest Fe–Fe and Fe–W distances in the alloy were determined to be 2.42 and 2.53 Å, respectively. The structures of mechanically alloyed (MA) M–W (M = Fe, Ni) alloys are similar to that of the as electrodeposited M–W (M = Fe, Ni) alloys. But these alloys include a small amount of undissolved pure Fe, Ni and W, also.