The influence of niobium in irradiation strengthening of dilute Zr-Nb alloys

Abstract
The irradiation damage configuration and yield stress response obtained in the c.p.h. α’and α phases in a Zr-2·7% Nb alloy after fast neutron irradiation have been studied as a function of pre-irradiation solute distribution. Largest yield stress increments were obtained for specimens irradiated with the solute initially in metastable solution, pre-irradiation ageing treatments reducing the yield stress response. Electron microscope studies have shown that the irradiation damage configuration was also determined by the solute super-saturation in the alloy phases, maximum strengthening being associated with a population of defect clusters or loops of < 30 Å diameter. A mechanism for the defect stabilization effect is proposed.