Consistent partial structure factors for amorphous Ni0.33(ZryHf1-y)0.67 using x-ray and neutron diffraction.

Abstract

We have determined all three partial radial distribution functions for amorphous ${\mathrm{Ni}}_{0.33}$${\mathrm{Zr}}_{0.67}$. Two independent sets of (Faber-Ziman) partial structure factors were obtained, one from x-ray diffraction on seven alloys with Hf isomorphously substituted for Zr and the other from combined x-ray and neutron diffraction on ${\mathrm{Ni}}_{0.33}$${\mathrm{Zr}}_{0.67}$ and ${\mathrm{Ni}}_{0.33}$${\mathrm{Hf}}_{0.67}$. The results are in agreement to better than 4%. Our study confirmed the reliability of the isomorphous substitution method in evaluating the partial structure factors of amorphous Ni-Zr(Hf) alloys providing that the size difference between Hf and Zr is taken into account. As a result, we have derived the Ni-Ni correlations for this composition. The sensitivity of the neutron structure factor to the light Ni atoms has revealed evidence for a Ni-Zr-Ni correlation beyond the first-neighbor shell.