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Theory and Modeling of Atomic Arrangements in Metallic Glasses Zbigniew H. Stachurski Research School of Engineering, CECS, Australian National University, Canberra ACT 0200, Australia e: [email protected] Abstract The understanding of the atomic-scale structure of solids began with the concept of translational symmetry, and has to a large degree come about because of the methods of X-ray crystallography. Theory of crystallography provides a datum from which the ideal atomic arrangements (and defects) in real materials can be determined. By comparison, no such universal laws or rules are well known for the atomic structure in amorphous solids, and for this reason we advance and promote the theoretical concept of an ideal amorphous solid (IAS) as a partial solution to this enigma. It will be shown that the IAS model provides an unambiguous basis for the understanding of atomic arrangements in metallic glasses. Metallic glasses solidify as amorphous solids with random arrangement of atoms. This is evidenced by direct experimental techniques, such as HRTEM, XRD, Atomic Probe, EXAFS, Raman and other. As real materials, BMGs contain imperfections in their random atomic structure. In order to describe these imperfections a reference state must be defined first (i.e., the IAS), and appropriate measures must be used to quantify these. It will be shown that taking the IAS model as the reference state, imperfections can be defined and their effects evaluated. In particular, it will be shown how: IAS can be used in deformation and fracture mechanics; detailed elastic, anelastic and plastic deformation mechanisms can be defined and used to predict deformation (as with dislocation, twinning and point defects motions in crystalline materials) IAS can be used in shear band propagation and instability by identifying the local cluster compositional deviations and instabilities IAS can be used to predict magnetic, electric, thermal and chemical properties by means of the aggregate theory IAS can be used to analyze the developments of nano-crystallinity IAS can be used in molecular dynamic modeling as the starting cell, thus not requiring pre-processing to equilibrate the structure and therefore saving significant run-time IAS can be used in design of new BMGs