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 σ_scl, which characterizes structural disordering and stability of the supercooled liquid state upon heating. A very good correlation of σ_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 η_scl based on the excess enthalpy of glass and showed that η_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.