Molecular Dynamics Simulations of Metallic Nanoglasses
Sara Adibi Sedeh (NUS), Paulo BRANICIO (IHPC), Shailendra Joshi (National University of Singapore)
Materials for Extreme Environments: Multiscale Experiments and Simulations
Mon 4:20 - 5:40
Salomon 203
Metallic glasses exhibit high strength and high hardness, but severe lack of tensile ductility. In order to improve the plasticity a new type of metallic glass architecture referred to as nanoglass has been recently proposed. Nanoglasses are synthesized by consolidation of ultrafine metallic glass powder and its microstructure comprises bulk glassy regions connected by grain boundary like interfacial regions that possess distinct amorphous density and structure compared to the bulk regions. In this work, we use molecular dynamics simulations to investigate the mechanical behavior of 2D Cu64Zr36 films nanoglass architecture over a range of particle sizes. The architectures are generated using Voronoi tessellation that qualitatively mimics the real synthesis approach. Results show that films with nanoglass architectures transition from a localized deformation in the form of a single dominant shear band to a near homogeneous plastic deformation with decreasing particle size. This is because the interfacial regions act as preferred channels for plasticity causing an interconnected motif of shear bands that depends on the microstructural size. In comparison, the metallic glass films with conventional architecture fail catastrophically through localization due to formation of a single dominant shear band. Together with the transition to a near homogeneous deformation and concomitantly enhanced ductility, the nano-glass films exhibit a consistent decrease in the yield stress compared to its conventional counterpart.