The effects of Ni or Nb additions on the relaxation behavior of Zr55Cu35Al10 metallic glass

Many questions raised in the field of metallic glasses (MGs) are inherently attributed to beta relaxation. Therefore, this study investigated the behavior of beta relaxation in the Zr55Cu35Al10 MG by differential scanning calorimetry (DSC) under different heating rates. Minor additions of Ni and Nb into the base alloy and pre-annealing process were also carried out to highlight the features of beta relaxation in the thermal curves. The results showed that the pre-annealing process led to the appearance of an endothermic peak under the glass transition temperature (T-g), which is a sign of reversible beta relaxation in the glassy structure. Moreover, the peak position of the endothermic event was at 0.78 T-g, 0.83 T-g, and 0.87 T-g for Zr55Cu35Al10, (Zr55Cu35Al10)(98)Ni-2, and (Zr55Cu35Al10)(98)Nb-2, respectively, which indicated the crucial role of minor addition on the evolution of beta relaxation. In addition, the pre-annealing process from 3 h to 48 h demonstrated that the endothermic peaks in the minor-added samples tended to shift to higher temperatures. Furthermore, structural characterization of MGs revealed various types of short-range and medium-range orders in the Ni- and Nb-added alloys, leading to a different relaxation behavior in the glassy structure.