Dynamics of Atomic Volume in CuZr Metallic Glasses

Typically, researchers attempt to identify specific microstructures to explain the dynamic behavior and physical properties of metallic glasses. However, the complex compositions and intricate structures of these materials make this approach particularly challenging. By treating atomic free volume as a tangible physical entity akin to an atom, and by investigating its temperature dependence and spatiotemporal evolution, we can gain new insights that may better elucidate these issues. In this study, we conducted a detailed comparison of the atomic excess volume in CuZr and CuZrAl metallic glass systems. Our findings indicate that CuZrAl has a higher thermal expansion coefficient. Although the spatial distribution of excess volume shows similar patterns in both systems, the CuZrAl system demonstrates greater uniformity. Furthermore, through calculating the volume relaxation function, we found that the volume relaxation process in CuZrAl is much slower than in CuZr, leading to a higher dynamics crossover temperature in the liquid state, which enhances its glass-forming ability (GFA).Our results offer fresh perspectives on understanding the GFA of metallic glasses.