Modeling of initial crystallization in the alloys Al–10Ni and Al–5Ni–2.7Y at high undercoolings

Formation and growth of crystallization centers of aluminum in amorphous alloys Al–10Ni and Al–5Ni–2.7Y have been studied by a method of the molecular dynamics. Local radial pair distribution functions were calculated for studying of structure. Growth kinetics of the comparatively large aluminum crystals in the binary system is studied. Latencies of appearance of the first crystallization centre are found. The energies of interatomic interaction averaged locally and also in the bulk of the amorphous phase are determined. It is researched how the size of the crystallization centre influences its structure and the local interaction energy. Formation of icosahedrons and their lifetimes are in consideration.

Research highlights
► Lifetimes of icasahedron clusters are larger than the lifetimes of FCC-clusters.
► Nuclei are formed in areas which are free from impurities and icasahedron clusters.
► Thermodynamic motive for growth of small crystallization centers is negligible.
► Ripening of crystallization centers without growth takes place in the ternary system.