SIMULATING STRUCTURE AND PHYSICAL PROPERTIES OF COMPLEX METALLIC ALLOYS
An introduction is presented to numerical methods, by which the behaviour of complex metallic alloys can be simulated. We primarily consider the molecular dynamics (MD) technique as implemented in our software package IMD, where Newton's equations of motion are solved for all atoms in a solid. After a short discourse on integration algorithms, some possible types of interactions are addressed. Already simple model potentials, as for example the Lennard-Jones-Gauss potential, can give rise to complex structures, where the characteristic length scales of the order by far exceed the range of the pair interaction. Realistic interactions are modelled by highly parametrized effective potentials, like the EAM (Embedded Atom Method) potential. Our program potfit allows to fit the parameters such that data from experiment or from ab-initio calculations are well reproduced. Several applications of the methods are outlined, notably the simulation of aluminium diffusion in quasicrystalline d-Al-Ni-Co, the computation of the phonon dispersion via the dynamical structure factor of MgZn2, the propagation of cracks in NbCr2, and an order-disorder phase transition in CaCd6.
