Relationship of structural disorder and stability of supercooled liquid state with glass-forming ability of metallic glasses

We performed calorimetric studies of 26 metallic glasses and calculated the excess entropy and excess enthalpy with respect to their counterpart crystals. On this basis, we introduced a dimensionless entropy-based parameter ${\sigma }_{scl}$, which characterizes structural disordering and stability of the supercooled liquid state upon heating. A very good correlation of ${\sigma }_{scl}$ with literature data on the critical cooling rate $R_c$ and critical diameter $D_{max}$ of metallic glasses is shown. We also introduced another dimensionless parameter ${\eta }_{scl}$ based on the excess enthalpy of glass and showed that ${\eta }_{scl}$ provides equally good correlation with $R_c$ and $D_{max}$. Possible relationship of structural disordering and glass-forming ability in the supercooled liquid range with the defect structure of glass is discussed. The obtained results provide a new window for the understanding of the glass-forming ability of metallic glasses.