Investigation of bulk metallic glass structure by means of electron irradiation

The sensitivity of radiation effects on structural features in metallic glasses (MG) provides a way of investigating the structure and structural defects of MG through the studies of accumulation and relaxation processes of radiation damages in the glasses. In particular, it is a way to verify the validity of models proposed for the MG structure. Currently, there are two theoretical structural models of MG, based on completely different concepts. On the one hand, the model of random closely packed spheres + free volume approach is based on the idea of “the ultimate disorder”. On the other hand, in the polycluster model the idea of altering and distorted short-range order is used. Each of the models implies fairly different kinds of primary radiation damages, relaxation kinetics, and other properties. We have studied the accumulation and recovery kinetics of radiation defects in ZrTiCuNiBe and ZrTiCuNiAl bulk metallic glasses irradiated with 2.5 MeV electrons at T ∼ 80 K. Electrical resistance measurements of the irradiated samples were performed. Dose dependences at ∼80 K and the recovery spectrum of irradiation-induced electrical resistance in the 85–300 K temperature range were obtained. The data suggest that the point defects are stable in the metallic glasses, and the defect mobility is a thermally activated process. The results obtained are evidently in accord with the polycluster model of the MG structure.