Research progress on the correlation between liquid fragile-to-strong transition and flow units in amorphous alloys
Abstract
<p indent="0mm">Amorphous alloys are an advanced class of metal materials obtained by rapid cooling of alloy liquids, which maintains the liquid-disordered structure by inhibiting crystallization. Based on the concept of liquid fragility proposed by Angell, during the cooling, the dynamic behavior of the alloy liquids generally undergoes a transition from fragile to strong, i.e., fragile-to-strong (F-S) transition. Flow units, a liquid-like structure that is “frozen” in the amorphous state during rapid cooling, can be used as dynamic defects to characterize the heterogeneous essential features of amorphous alloys. Due to the heritability of liquid-solid transition, the dynamic behavior of liquid has an important influence on the dynamic defects in the amorphous state, and can even be regarded as its liquid origin. This paper summarizes the recent research progress on the correlation between liquid F-S transition and the flow units in the amorphous state. The dynamic heredity relation between the activated atoms that induce F-S transition found in molecular dynamics simulations and flow unit is introduced. The correlation between the strength of F-S transition and the features of the flow units is analyzed with the help of the dynamic relaxation coupling degree. This not only helps to deepen the understanding of the intrinsic correlation between liquid and amorphous states, but also provides guidance for the material design of amorphous alloys from the perspective of liquid regulation.</p>
