Abnormal bonding ways in Zr50Cu50 metallic glass under high pressures

The atomic structures of Zr₅₀Cu₅₀ metallic glasses (MGs) under high pressures from 0 GPa to 150 GPa are investigated via molecular dynamics simulations. We found that as pressure and density increase, local structural parameters such as coordination number, five-fold symmetry and quasi-nearest atom reach maxima (or minima) at 60 GPa, rather than monotonous pressure dependence. Atomic structure analyses uncover unexpected shortening of Zr-Zr bonding of Zr₅₀Cu₅₀ MGs under high pressures, responsible for the change of atomic packing in Zr₅₀Cu₅₀ MGs from dense to loose while pressure increasing. Furthermore, composition segregation is observed at high pressures, resulted from the new finding that the Zr-Zr and Cu-Cu bonding are much easier to decrease than Zr-Cu under high pressures. The results help to understand the behaviors of metallic glasses under extreme conditions.