title: Key factors affecting mechanical behavior of metallic glass nanowires.
abstract: Both strengthening and weakening trends with decreasing diameter have been observed for metallic glass nanowires, sometimes even in the samples with the same chemical composition. How to reconcile the results has reminded a puzzle. Since the detailed stress state and microstructure of metallic glass nanowires may differ from each other significantly depending on preparation, to discover the intrinsic size effect it is necessary to study metallic glass nanowires fabricated differently. Here we show the complex size effects from one such class of metallic glass nanowires prepared by casting using molecular dynamics simulations. As compared with the nanowires of the same composition prepared by other methods, the cast nanowires deform nearly homogeneously with much lower strength but better ductility; and also show strengthening in tension but weakening in compression with decreasing wire diameter. The subtle size dependence is shown to be related to the key factors including internal and surface stress state, atomic structure variation, and presence of various gradients. The complex interplay of these factors at decreasing size leads to the different deformation behaviors.
authors.affiliation: Nanophotonics and Optoelectronics Research Center, Qian Xuesen laboratory of Space Technology, China Academy of Space Technology, Beijing, 100094, China.|School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States.
authors.forename: Qi
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083, China.
authors.forename: Qi-Kai
authors.initials: QK
authors.lastname: Li
authors.affiliation: School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States.|State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083, China.
authors.forename: Mo
authors.initials: M
authors.lastname: Li