The study of microstructural defects and mechanical properties in proton-irradiated Zr-1.0%Nb-1.0%Sn-0.1%Fe

We had earlier analysed point defects in irradiated Zr-1.0%Nb-1.0% Sn-0.1%F e samples by positron annihilation lifetime spectroscopy (PALS). The studie s revealed the generation of irradiation induced di- and tri-vacancy cluste rs. In the present work, we have carried out X-ray diffraction line profile analysis (XRDLPA) and studies of mechanical properties like ultimate tensi le strength (UTS), yield strength (YS) and percentage elongation (%E) on th e same irradiated samples at different doses. XRDLPA reveals that order of dislocation density remains almost unchanged up to the experimental limit o f irradiation dose. Attempts have also been made to correlate the changes i n mechanical properties with irradiation-induced defects. YS of the alloy i ncreases with irradiation due to locking, or pinning of dislocations with v acancy clusters. However, there is an anomaly in YS at a dose of 5 x 10(20) protons/m(2) which has been explained in the light of interaction of vacan cies with solute atoms. Percentage elongation on the other hand, shows a mo notonic fall with increasing dose. (C) 2001 Elsevier Science B.V. All right s reserved.