Ni-Nb-Ta bulk metallic glasses designed by a cluster-plus-glue atom model

摘要

The formation of Ni-based ternary Ni-Nb-Ta bulk metallic glasses (BMGs) is explored in this work. Alloy compositions are designed by the cluster-plus-glue atom model based on a eutectic-related binary cluster Ni-Ni₆Nb₆, which is derived from the binary eutectic crystalline phase NiNb (Fe₇W₆ type). According to the cluster-plus-glue atom model, the well-known binary BMG-forming composition Ni₆₂Nb₃₈ can be described by a composition formula [Ni-Ni₆Nb₆]Ni₃ = Ni_62.5Nb_37.5. With an aim to further improve the glass-forming ability of the Ni-Nb alloy, Ta is selected as an alloying addition to partially replace Nb in the [Ni-Ni₆Nb₆]Ni₃ composition formula. The experimental results verified that BMGs with a critical size of 3 mm can be achieved at compositions [Ni-Ni₆Nb_6−xTa_x]Ni₃ (x = 0.9 ∼ 1.1). Thermal and mechanical properties of the obtained BMG alloys are also investigated.