Abstract
Samples of polycrystalline zirconium were irradiated with fast neutrons (E>0.1 MeV) in Pakistan Research Reactor-1 at 423 K to fluences 1.22×10
20
, 4.87×10
20
and 9.70×10
20
n/m
2
. Mechanical properties such as yield stress (YS), ultimate tensile stress (UTS), percentage elongation, stress relaxation rate and hardness of the samples were measured before and after irradiation to analyze post-irradiation effects. The results indicate that neutron irradiation of polycrystalline zirconium does not produce any significant change in its mechanical properties. The YS, UTS and hardness slightly decrease, whereas the percentage elongation increases with an increase in the radiation fluence. Stress relaxation rate was found to be unaffected after irradiation. The post-irradiation microstructure of zirconium reveals that the surface of the material becomes rough by increasing the radiation fluence. X-ray diffraction analysis of the specimens indicates a decrease in the intensity of Bragg's reflection with an increase in the radiation fluence. The insignificant changes in the mechanical properties of zirconium after irradiation are attributed to low defects production in irradiated zirconium and subsequently their recombination due to irradiation temperature.