Structural Origins for Enhanced Thermal Stability and Glass-Forming Ability of Co–B Metallic Glasses with Y and Nb Addition

The effects of Y and Nb addition on thermal stability, glass-forming ability (GFA), magnetic softness Co75B25 metallic glass (MG) were comprehensively investigated. experimental results indicated that the GFA, studied MGs increase in order < Co73Nb2B25 Co71.5Y3.5B25 Co69.5Y3.5Nb2B25. structural origins improved properties revealed by ab initio molecular dynamics (AIMD) simulations density functional theory (DFT) calculations. Results showed B-centered prism units are primary structure-forming four MGs, connect through vertex-, edge-, face-shared (VS, ES, FS) atoms, Co-centered tend to with Co/B-centered via intercross-shared (IS) atoms. not only plays role connecting atoms but also enhances both bond strengths fractions icosahedral-like increasing Co69.5Y3.5Nb2B25, which is conducive enhancement atomic packing density, viscosity, thereby improving stability GFA. In addition, improvement homogeneity leads enhanced softness.