Calculation of some metallic glass properties, based on the use of a Gaussian distribution for the nearest-neighbour distance

Abstract

Abstract A number of properties of metallic glasses are explained or reproduced in a semi-quantitative way, starting from a Gaussian distribution for the nearest-neighbour distances and an interatomic potential picture. The experimentally observed change of the mean atomic volume is explained in a natural way, by making use of an anharmonic contribution to the potential. The statistical distribution for the volume per atom and the coordination number is calculated, and it is shown that the results agree well with published simulation data. The mean atomic energy, crystallization energy and irreversible relaxation energy are expressed as a function of the dispersion for the Gaussian distribution σ, or of Δσ (the change of σ during annealing). A number of relations between relevant physical parameters are thereby derived, which are indeed confirmed by experiment within reasonable accuracy. Special attention is paid to enthalpy changes during reversible and irreversible structural changes, both described by a two-level state picture. Estimates are made of the statistical distribution of the relative energy difference between the initial and final level of the two-level states. Using these results, several trends in experimental data can be explained.