Fragility constitutes a major parameter of supercooled liquids. The phenomenological definition of this quantity is related to the rate of a change of the shear viscosity η at the glass transition temperature. Although a large number of correlations of the fragility with different properties of metallic glasses were reported, an adequate understanding of its physical nature is still lacking. Attempting to uncover this nature, we performed the calculation of the fragility within the framework of the interstitialcy theory (IT) combined with the elastic shoving model. We derived an analytical expression for the fragility, which shows its relation with the high-frequency shear modulus G in the supercooled liquid state. To verify this result, specially designed measurements of η and G were performed on seven Zr-, Cu- and Pd-based metallic glasses. It was found that the fragility calculated from shear modulus relaxation data is in excellent agreement with the fragility derived directly from shear viscosity measurements. We also calculated the heat capacity jump ΔC _sql at the glass transition and showed that it is related to the fragility and, consequently, to shear modulus relaxation. The ΔC _sql-value thus derived is in a good agreement with experimental data. It is concluded that the fragility and heat capacity jump in the supercooled liquid state can be determined by the evolution of the system of interstitial-type defects frozen-in from the melt upon glass production, as suggested by the IT. This connection is mediated by the high-frequency shear modulus.

脆性构成过冷液体的主要参数。该量的现象学定义与玻璃化转变温度下剪切粘度η的变化率有关。尽管报告了大量脆性与金属玻璃不同性质的相关性，但对其物理性质仍缺乏足够的了解。为了揭示这种性质，我们在间隙理论 (IT) 的框架内结合弹性推挤模型进行了脆性计算。我们推导出了脆性的解析表达式，该表达式显示了脆性与过冷液态下的高频剪切模量G 的关系。为了验证这一结果，专门设计的测量η和G在七种 Zr-、Cu- 和 Pd 基金属玻璃上进行。发现从剪切模量松弛数据计算的脆性与直接从剪切粘度测量得出的脆性非常一致。我们还计算了热容量跳跃Δ Ç _SQL在玻璃化转变，并表明它是有关的脆弱性，因此，向剪切模量松弛。该Δ Ç _SQL得出的-值与实验数据非常吻合。得出的结论是，如 IT 所建议的那样，过冷液态下的脆性和热容跳跃可由玻璃生产过程中从熔体中冻结的间隙型缺陷系统的演变来确定。这种连接是由高频剪切模量介导的。