Relationship between chemical and icosahedral local orderings in Al-Ni-Fe melts

Abstract

An X-ray diffraction study and simulation of the structure of ternary Al81.6Ni14.9Fe3.5, Al71.6Ni23Fe5.4, and Al61.1Ni31.1Fe7.3 melts by the reverse Monte Carlo method are conducted. An analysis of the structural models of melts is performed by the Voronoi-Delaunay partition. It is shown that the prepeak on the structure factor curves in the diffraction vector range of 13 nm−1 to 22 nm−1 is due to two factors: chemical ordering of atoms and non-crystalline close packing. The origin of the icosahedral short-range order in the melts as one of the variants of ordering of atoms in non-crystalline close packed clusters is discussed.