Short-to-medium range structure and glass-forming ability in metallic glasses

Jingli Ren

Henan Academy of Big Data, Zhengzhou University, Zhengzhou 450052, China

EXTENDED ABSTRACT: Metallic glasses (MGs) with many superior mechanical and physical properties and thus have attracted tremendous research interest across the general field of condensed matter physics and materials science. These excellent properties are closely related to the structural characteristics of short-range order and long-range disorder. However, it is a though work to explore the stacking of short-range to long-range structure. Therefore, understanding the underlying physics as well as charactering the order degree of structural units in a quantitative manner is the most challenge issues in glass physics and material science. Moreover, exploring suitable experimental conditions that MGs are easy to form according to atomic structure is conducive to the application. This study investigates the atomistic models, changes of structural units with scale, and glass forming ability in response to variant compositions and cooling rates. The structural units are obtained by molecular dynamics and hierarchical clustering. In the clustering model, a nesting relationship from small-scale units to large-scale units, i.e., from short-range order to medium range order, is observed during the hierarchical clustering. Moreover, the orderly evolution of structural units is characterized by the skewness and fractal dimension. The skewness increases but the fractal dimension decreases with increasing the scale size, which indicates that the order degree is descending. Interestingly, the result about the packing efficiency of structural units suggests that an exorbitant cooling rate will inhibit glass-forming ability.