Crystallization behavior of preannealed bulk amorphous alloy Zr62Al8Ni13Cu17

Isochronal and isothermal heating methods by differential scanning calorimetry (DSC) were used to investigate the effects of sub-Tg relaxation on the subsequent crystallization of a Zr62Al8Ni13Cu17 bulk amorphous alloy. It was found that the activation energy by Kissinger's equation couldn't fit to describe the crystallization behavior of the samples after preannealing. Actually, pre-annealing decreased the incubation time by promoting the formation of critical clusters while increased the activation energy for the following growth. Avrami exponents for the as-quenched samples kept a constant of about 3.5∼3.9 but for the pre-annealed samples deviated from the linear Johnson–Mehl–Avrami (JMA) mode. The different nucleation and growth mechanism affected by structural relaxation was explored.