The effect of fast neutron damage on the deformation of Copper-Tin alloys

Abstract

The deformation behaviour of several copper-tin alloys was examined before and after irradiation with fast neutrons. It was found that the first measurable change in all of the alloys occurred at a dose between 10 16 and 10 17 n.v.t. and, although the initial flow stress of unirradiated alloys decreased with tin content, all of the alloys reached the same maximum flow stress at a saturation dose of approximately 3 × 10 19n.v.t. The dependence of the flow stress upon grain size was examined and it was found that the friction stress of irradiated alloys decreased linearly with strain and that the initial dislocation sources were heavily jogged. The jogged sources were eliminated by a few percent of strain. A simple theory for irradiation hardening, which predicts a complex relationship between stress and fast neutron dose and between stress and temperature, is proposed. The agreement of the experimental results with this theory is good.