Non-isothermal crystallization behavior of U-based amorphous alloy

The non-isothermal crystallization behavior of uranium-based amorphous alloy U64Co28.5Al7.5 was investigated by using differential scanning calorimetry. Its kinetic fragility parameter, overall crystallization activation energy and Kauzmann temperature were determined to be 28, 234 kJ/mol and 580 K, respectively. The evolution of the crystallization activation energy with the volume fraction crystallized, which was established by both the Kissinger and Ozawa methods independently, suggests a typical three-staged process for the crystallization. As reflected by the change of the local Avrami exponent with the fraction crystallized, nucleation dominates the whole process that can be illustrated phenomenologically with the percolation model. This work is helpful for understanding the formation and thermal stability of U-based amorphous alloys, and also for the development of new materials of this kind.