Short-range order in undercooled and stable melts forming quasicrystals and approximants and its influence on nucleation

An icosahedral short-range order has been predicted to prevail in undercooled metallic melts. For melts of pure metals, this hypothesis was recently experimentally confirmed by diffraction experiments. This paper presents results of neutron scattering experiments on the short-range order of stable and undercooled liquids of alloys forming quasicrystals and polytetrahedral crystals. The studies indicate that an icosahedral topological short-range order prevails in all of the investigated melts. The influence of this icosahedral short-range order on the nucleation behaviour of solid phases from the undercooled liquid is discussed.