Glass Transition Kinetics of 2714A amorphous alloy

The present study is related to the kinetics of onset crystallization, T-x and peak crystallization T-p of cobalt based metallic glass 2714A (Co65Si15B14Fe4Ni2) using Differential Scanning Calorimetry (DSC). Non-isothermal measurements were performed at different heating rates (2, 4, 6, 8 and 10 K/min). The experimental results of the crystallization were studied by two most frequently used methods, i.e., Moynihan and Kissinger. The onset crystallization was also studied by VFT and Lasock's approaches in addition to the above two methods. The activation energy of crystallization E-c was found to be 622.86 and 638.28 kJ/mol and E-x the activation energy of onset crystallization to be 676.34 and 688.93 kJ/mol respectively. Here T-x is used as a substitution of T-g to calculate the fragility index m of the cobalt based metallic glass in the absence of T-g. The fragility index, m which is a measure of glass forming ability (GFA) is also calculated and the value falls between 20 and 60. This indicates the studied metallic glass is an intermediate strong glass.