Hardening of ferritic alloys at 288 deg. C by electron irradiation

Tensile specimens of a commercially pure iron, an iron-copper alloy and two ferritic pressure vessel steels, were irradiated at 288 deg. C with 2.5 MeV electrons to doses of 2.82x1023 and 9.35x1023 e-/m2, corresponding to calculated atomic displacement doses of 9.53x10-4 and 3.16x10-3 dpa, respectively. Tensile tests at room temperature showed dose-dependent increases in yield stress and ultimate tensile stress and reductions in uniform elongation, compatible with literature data for A533B steel neutron-irradiated at 288 deg. C to similar displacement levels. No systematic effect of copper content was discerned in these electron irradiations, contrary to expectations based on neutron irradiations. For the limited dose range over which direct comparison can be made, it is concluded that the hardening efficiency of electron irradiations per unit dpa at 288 deg. C is similar to that for neutron irradiations