Kinetics of glass transition of La65Al20Co15 metallic glass

•The kinetics of glass transition of La65Al20Co15 metallic glass was investigated.•The heating rate dependence of the glass transition temperature was determined.•Evidence of variation of E with temperature was observed.•The variation of E with temperature was analyzed using isoconversional methods.•Multiple-step reactions involving relaxation process and mechanism were demonstrated.

The glass transition kinetics of melt-spun La65Al20Co15 amorphous alloy ribbons has been investigated using differential scanning calorimetry (DSC) technique with continuous heating of the sample at different heating rates. The dependence of the glass transition temperature (Tg) on the heating rate (β) has been determined by Lasocka’s relationship. The activation energy (E) of the glass transition has been obtained by employing Moynihan and Kissinger methods, respectively. It is found that the glass transition process cannot be described in terms of single activation energy. The variation of E with the extent of conversion (α) is further analyzed by using two iso-conversional methods. It is observed that the E of glass transition demonstrates a significant increase with the extent of conversion from amorphous to supercooled liquid phase of La65Al20Co15 metallic glass.