Structure-phase transformations in the Be–Fe–Be layered system subjected to irradiation and thermal treatment Original Research Article

The methods of Mössbauer spectroscopy at 57Fe nuclei were used to study changes in structure-phase states of the Be–Fe–Be three-layer system subjected to isothermal annealing, irradiation with helium ions of energies up to 40 keV followed by a series of isochronous annealings. Upon the consequent isothermal annealings at 650 °С, the samples represented a layered system. Its bulk was represented by α-Fe(Be) solid solution and near-surface areas at both sides were mainly represented by FeBe2 intermetallic compound. Irradiation of the near-surface layers resulted in their local enrichment with beryllium atoms. The rate of enrichment depended on the dose, and the dose varied from 1×1021 up to 2×1022 ion/m2. Following consequent 2-hour long isochronous annealings at temperatures from 200 to 650 °С resulted in almost complete recovery of the local concentration of the components and the structure in the irradiated near-surface layers.