Computational study of tensile deformation of a constrained nanoscale metallic glass

In this study a nanometer-sized metallic glass (nano-MG) Ti ₅₀Cu₅₀ was generated with constrained atoms at both ends and was extended until fracture under a tensile load by molecular dynamics simulation using the general embedded-atom model (GEAM) potential. Totally different mechanical behavior was observed in the nano-MG, such as strain hardening and necking, both of which have been discovered in a few real and simulated MGs and can be related to the generation of shear transformation zones (STZs). A dramatic drop in Young's modulus was found due to the surface effect. Such effect results from the large fraction of surface atoms which have a different surrounding configuration from bulk atoms. At fracture the nano-MG breaks by atomic separation as reported in metal nanowires. The fracture strain is as large as about 120%, indicating that nano-MGs are intrinsically ductile. © 2010 World Scientific Publishing Company.