Crystallization Kinetics of the Fe68Nb6B23Mo3 Glassy Ribbons Studied by Differential Scanning Calorimetry

Fe-based metallic glass has wide industrial application due to its unique mechanical behavior and magnetic properties. In the present work, the non-isothermal crystallization kinetics in Fe68Nb6B23Mo3 glassy alloys were investigated by differential scanning calorimeter (DSC). The results indicate that both the glass transformation and crystallization process display an obvious kinetic effect. The activation energy is calculated using Kissinger's method and Ozawar's method. The activation energy for T-g (glass transition temperatures), T-x (crystallization initiation temperatures) and T-p (crystallization peak temperatures) calculated from Kissinger equation, is 308 +/- 4, 342 +/- 5 and 310 +/- 7 kJ mol(-1), respectively. The activation energy for T-g, T-x and T-p calculated from Ozawa equation is 322 +/- 3, 356 +/- 5 and 325 +/- 7 kJ mol(-1), respectively. With the increase of the crystallization volume fraction x, the Avrami exponent n(x) first decreases and then increases. At the preliminary step, 0 < x < 0.25, 2.5 < n(x) < 4.0 stands for the growth from a small size with an increasing nucleation rate. When 0.25 < x < 0.71, n(x) decreases from 2.5 to 1.5, indicating that this stage is controlled by the growth of small particles with a decreasing nucleation rate.

Automated summary

The non-isothermal crystallization kinetics of Fe68Nb6B23Mo3 metallic glass was investigated using DSC and the activation energy was calculated. Both the glass transformation and crystallization process showed kinetic effects. The growth mode of nuclei changed with the increase of crystallization volume fraction.