Atomistic simulation study of favored compositions of Ni-Nb-Al metallic glasses

This study investigates the formation process of Ni-Nb-Al metallic glasses. To this end, a long-range n -body potential was constructed for the Ni-Nb-Al ternary metal system, and applied to atomistic simulations. The simulations not only showed the physical origins of the amorphous phase formation, but also quantitatively predicted a hexagonal compositional region that energetically favors the glass formation. The energy difference between the solid solution and metallic glass, which generates the amorphization driving force (ADF), was suggested to indicate the glass-formation ability (GFA) of each alloy. Based on the computed ADFs, the Ni 55 Nb 25 Al 20 alloy exhibited the highest GFA among the Ni-Nb-Al members, implying that the glass formed by this amorphous alloy is more thermodynamically stable than other alloys in the system. In a Voronoi tessellation analysis, the knee point of the coordination-number distribution curve corresponded to the glass-formation region of the Ni-Nb-Al system.