Correlation between fragility and glass-forming ability/plasticity in metallic glass-forming alloys

In the present study, the authors draw attention to the relationship among fragility index (m), glass-forming ability (GFA), and plasticity in various metallic glass-forming alloys (MGAs), and show that the m value is closely related to both characteristics. In particular, m can be formulated with ν (Poisson’s ratio): ν=−0.179+0.312logm, which means that high m as well as large ν values might be regarded as indicators of the MGAs ductility. As an example, it can be rationalized that the lowest m value (21.5 at 5K∕min) of Ca65Mg15Zn20 supports both outstanding GFA and extreme brittleness.