Influence of packing density and viscosity on the growth of dynamic heterogeneity while cooling metallic melts

Abstract

One of the most intriguing aspects of glass-forming melts is the existence of specially separated regions whose dynamics can differ from each other by several orders of magnitude and is known as dynamic heterogeneity (DH). In this letter, we have studied the growth of DH in three glass-forming metallic melts with different glass-forming ability, packing density and viscosity. The results show that when the temperature approaches the melting point, the size of DH grows exponentially in good glass-forming melts but linearly in poor ones. Additionally, the growth of DH with packing density and viscosity in the binary melt shows similar behavior, but in the ternary melt no significant change in the growth of DH exists while the viscosity increased. Interestingly, at a packing density of approximately 0.531 ± 0.003, the growth of DH is much faster in the studied metallic melts. These results indicate that the packing density of glass-forming liquids is the dominant factor that governs the growth of DH in metallic melts.