Recovery of yield stress in dilute Ni alloys after electron and neutron irradiations at low temperatures

Yield stress increase due to electron and neutron irradiations at low temperatures and the isochronal annealing behaviour after the irradiations have been studied by tensile tests in seven kinds of dilute Ni alloys and pure Ni. In the electron irradiation at 78 K, the yield stress increase was remarkably large in the alloys with an undersized solute, Si, and oversized ones with large atomic size misfit, such as Au and In. Two recovery stages II (78-300 K) and III (300-450 K) appeared in the isochronal curves after the irradiation. Stage II was not found in the alloys with oversized solutes of Au, In and Mn. On the contrary, the yield stress recovery in stage III increased with atomic size of the solutes in Ni, and the maximum recovery temperature shifted to higher temperatures. Little effect of solutes on the radiation-induced yield stress increase at 78 K and isochronal annealing behaviour from 78 to 723 K were observed in the case of neutron irradiation. (orig.)