Concentration dependence of partial vibrational spectra in Ni-Nb and Cu-Zrmetallic glasses

The neutron inelastic scattering of the Ni44Nb56 and Cu33Zr67 metallic glas ses with isotope substitution for Cu and Ni were measured. The results are compared to earlier data for Ni62Nb38 and Cu64Zr36 (Ni and Cu isotopic subs titution). Availability of two samples with different isotope content for e ach system has enabled partial vibrational densities of states to be obtain ed for both materials. The ratios of average force constants, B-Ni/B-Nb and B-Cu/B-Zr, and mean-square atomic displacements, [u(2)], for Ni, Nb, Cu an d Zr atoms are estimated. The interatomic interaction of the Ni and Cu atom s with respect to all neighbours is less than that of the Nb and Zr atoms. With decrease of the content of Ni and Cu atoms the differences of the aver age force constants in each system decline. (C) 1999 Elsevier Science B.V. All rights reserved.