Crystallization kinetics of a high-zirconium-based glassy alloy: A DSC study

The non-isothermal and isothermal crystallization kinetics of Zr_72.5Al₁₀Fe_17.5 glassy alloy was investigated using differential scanning calorimeter (DSC). Under non-isothermal heating condition, the primary phase in the initial crystallization is Zr₆Al₂Fe phase and the final crystallized products consist of Zr₆Al₂Fe, Zr₂Fe and a-Zr phases. The apparent activation energy for crystallization estimated using the Kissinger method is 342.1 ± 8.1 kJ/mol. The local activation energy decreased with the increase in the crystallization volume fraction during nonisothermal crystallization. Under isothermal heating condition, the average Avrami exponent of about 2.76 implies a mainly diffusion-controlled three-dimensional growth with an increasing nucleation rate. The local activation energy for isothermal crystallization shows a different variation trend from that for nonisothermal crystallization, indicating different nucleation-and-growth mechanisms for the two crystallizaiton conditions.