Formation and deformation of metallic glasses: Atomistic theory

The free-volume theory has been successful in describing various structural and mechanical properties of metallic glasses, and continues to be used nearly half a century after it was created. However, the validity of the free-volume model at an atomistic level is questionable. We suggest that the apparent success of the free-volume model is that it represents the fictive temperature of the system well, rather than its microscopic reality. We propose an alternative approach based upon the exchange and fluctuation of atomic bonds, described in terms of the atomic level stresses. This approach enables much more quantitative description of the properties of metallic glasses, including glass transition, liquid fragility, glass formation and mechanical deformation.