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-Ni_6Nb_6, which is derived from the binary eutectic crystalline phase NiNb (Fe_7W_6 type). According to the cluster-plus-glue atom model, the well-known binary BMG-forming composition Ni_(62)Nb_(38) can be described by a composition formula [Ni-Ni_6Nb_6]Ni_3 = Ni_(62.5)Nb_(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-Ni)6Nb)6]Ni)3 composition formula. The experimental results verified that BMGs with a critical size of 3 mm can be achieved at compositions [Ni-Ni)6Nb_(6-x)Ta_x]Ni_3 (x = 0.9 ~ 1.1). Thermal and mechanical properties of the obtained BMG alloys are also investigated.