Computer simulation of density and pressure variations in amorphous metals

Computer simulations are performed on amorphous one-component systems with an isotropic smooth pair interaction and periodic boundary conditions. It is found that after careful static relaxation vacancies, vacancy clusters, voids and slightly compressed regions of cylindrical and spherical symmetry, but not planar symmetry, are stable. The author concludes that these defects can exist at zero temperature in real amorphous systems since realistic (anisotropic, oscillating, three-body) interactions tend to increase the stability beyond that of the author's simple model. The effect of various potentials and of positive and negative pressure on the stability of defects is investigated. Methods for definition and sensitive detection of density and pressure variations are presented.