Moessbauer spectroscopy study of aging and fast neutron irradiation effects in a copper-rich Cu-Fe alloy

Mössbauer spectroscopy, supplemented by resistivity measurements, was used to follow the effects of thermal aging and fast neutron irradiation on precipitation processes in a Cu- 0.6 at % Fe alloy. The characterization of spectra of solution annealed and aged alloy samples provides background for interpretation of the complex effects occurring in irradiated alloys. Both irradiation-induced aging and dissolution effects were observed as a function of pre-irradiation heat treatment. In as-quenched alloys, fast neutrons cause the formation of very small Fe clusters (< 12 atoms). In aged alloys, fast neutron induced displacement spikes disperse Fe atoms existing in clusters and precipitates. The dissolution effect is dependent upon the stage of aging or initial Fe cluster size.