Computer Simulation of Amorphous Ni–Nb Alloys from Diffraction Data

Abstract

Diffraction data are used to develop 300-K models of the amorphous Ni62Nb38 and Ni44Nb56 alloys using a “hybridization” algorithm, in which the force functions for each atomic pair are linear combinations of those generating the structure of the alloy at 0 and 300 K. These force functions are found using the Schommers algorithm at 300 K and the “coordination number comparison algorithm” (proposed in this work) at 0 K. The pair correlation functions thus found agree well with the diffraction data. The calculated vibrational densities of states for the Ni and Nb atoms in the amorphous alloys studied are in reasonable agreement with inelastic neutron scattering data. The calculated heat capacity of Ni62Nb38 agrees well with experiment, while that of Ni44Nb56 is lower than the reported values.