Pressure effects on the dynamics and glass formation of Cu-Ag eutectic melt

Abstract

The effects of pressure on the dynamic property and glass transition of Cu54.2Ag45.8 eutectic melt were systematically studied by extensive molecular dynamics simulations. It is shown that an increasing external pressure can slow down the dynamics of the melt and enhances the dynamic heterogeneity. As the pressure increases, the dynamic crossover temperature and glass transition temperature monotonously increase. Application of an external pressure to the melt is conducive to formation of <0, 3, 6, 4> and <0, 3, 6, 3> polyhedrons in the metallic glass, but unfavorable for formation of <0, 0, 12, 0> clusters. The increase of pressure results in an inverse structure-energy relationship in the relaxed glass, i.e., the potential energy increases with increasing atomic packing density, because the relaxation of local structure into the low-energy configuration is restricted. Finally, the effects of temperature and pressure on the microstructure evolution during glass formation were compared.