Energetically deposited cluster assembly of metallic glasses

Metallic glasses, prepared by rapid quenching and ball milling, have been studied extensively for decades. Nevertheless, they are not as well understood as crystalline materials in terms of structure and lo-cal atomic packing. The assembly of amorphous nanoclusters by energetic deposition has recently been shown as an alternative route to synthesize amorphous films. Furthermore, the local atomic structures of these cluster-assembled films were found to be different from that of the rapidly quenched metallic glass of the same composition. However, the underlying mechanisms, which result in these novel struc-tures of the cluster-assembled films are hitherto unknown. An atomistic molecular dynamics study of the formation of Cu50Zr50 cluster-assembled metallic glass films is presented. Two amorphous phases are identified: one in the cores of the clusters, and the other in the continuous network of interfaces formed amongst the clusters. These two phases are chemically distinct from one other and also different from the rapidly quenched metallic glasses. An increased short-range order is observed in the interfaces, while the cores occupy lower energy states. The present results further demonstrate that the amorphous short -and medium-range orders of cluster-assembled glasses not only differ from rapidly quenched glass of the same macroscopic composition, but can be tailored by the variation of the deposition energy.(c) 2022 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.