Intermediate-range order in amorphous metal alloys

Amorphous metal alloys sometimes contain order beyond that of a simple glass. The paracrystalline model for such a metallic glass is described and its predictions compared with published data. These data were obtained by the recently developed technique of fluctuation electron microscopy (FEM), which is also described. The paracrystalline model results compare well with data from a sample that, from its diffraction pattern, was clearly polycrystalline, although with very small crystallites. The model predicts only small FEM signals from samples that appear to be amorphous by their diffraction patterns.