Reversible structural relaxation and crystallization of Zr62Al8Ni13Cu17 bulk metallic glass

The effect of pre-treatment above glass transition temperature (Tg) on the reversible structural relaxation in a Zr62Al8Ni13Cu17 bulk metallic glass at sub-Tg annealing has been investigated. It is found that the enthalpy relaxation can be well described by a stretched exponential function. A free-volume model can only qualitatively simulate the process of enthalpy recovery. Sub-Tg heat treatments after enthalpy recovery have almost no effect on the following crystallization, which can be accelerated when critical clusters are formed for a longer time annealing.