Process-structure-mechanical property relationships in Cu-Zr nanoglass: Insights from molecular dynamics

Abstract

Nanoglasses (NGs) as a novel type of amorphous material with tunable microstructure have paved the way for engineering the structure of amorphous materials with tailored performance. Central to this effort is modifying microstructural features (through altering processing routes), which is made possible by a comprehensive understanding of process-structure-properties relationships. Research on NGs has frequently limited its scope to specific processing parameters or focused solely on identifying trends. This study provides a comprehensive investigation of the process-structure-mechanical property relationships in Cu-Zr NGs by employing molecular dynamics simulations. It focuses on how main process parameters like temperature, glass quenching rate, core grain size, and composition affect NGs' structural characteristics and mechanical behavior. The findings indicate that process parameters such as temperature, glass quenching rate, and composition substantially affect atomic volume profiles and the formation of Voronoi clusters. Conversely, grain size specifically influences the volume fractions of the constituent phases. Analysis of NGs’ mechanical responses under diverse processing parameters reveals that generally, any process parameters that induce excess free volume along with loosely-packed clusters result in lower ultimate strength and a softer elastic response. Additionally, the post-ultimate tensile strength behavior and degree of homogeneous plasticity in NGs are primarily influenced by the grain size. Moreover, investigation of deformation mechanisms reveals three phases: the nucleation of shear-activated atoms, the activation of shear transformation zones, and the shear localization. The findings lay the groundwork for the material design of NGs with enhanced mechanical performance through controlling processing conditions, offering practical applications in harsh environments.