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

TL;DR

This study introduces entropy- and enthalpy-based parameters to quantify structural disorder and stability in supercooled metallic liquids, correlating these with glass-forming ability metrics like critical cooling rate and maximum diameter.

Contribution

It proposes new dimensionless parameters {}scl and {}scl that effectively relate structural disorder to glass-forming ability in metallic glasses.

Findings

{}scl correlates with critical cooling rate and maximum diameter.

{}scl also shows strong correlation with glass-forming ability.

Results offer new insights into the role of structural disorder in metallic glass formation.

Abstract

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 Rc and critical diameter Dmax 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 Rc and Dmax. 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 understandingof the glass-forming ability of metallic glasses.