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

Abstract

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 Ni 4 W 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.