Radiation damage in a Ni64Zr36 glass

It seems that glass is not susceptible to radiation damage unless it contains the molecules being chemically disrupted. However, recent works have shown that metallic glasses can be structurally modified by irradiation with neutrons, heavy ions, fission fragments and electrons, and their various properties change significantly. There studies were carried out on both metal-metal glasses and the glasses containing metalloids. Some research suggested that the defects with atomic scale dimensions were produced, and it resulted in excess free volume. The aim of this research was to assess the radiation damage by four tests on (1) the release of heat before and during crystallization, (2) the change of crystallizing temperature determined by calorimetry, (3) the anomaly of free volume assessed by dilatometry, and (4) the change of diffusion coefficient due to irradiation. Two glasses, Ni64Zr36 and Ni33Zr67, were selected, and irradiation was made with fast neutrons. The experimental procedure and the results are reported. The irradiated samples showed very substantial preliminary heat release. A part of the irradiated glasses crystallized to form anomalous metastable species, and the remaining glasses crystallized into the normal form. Also partial relaxation took place. (Kako, I.)