Solute Interactions with Point Detects In HVEM Irradiated Zirconium Alloys

Abstract

Samples of Zr, Zr-0.5sn, Zr-0.5Fe, Zr-0.5cr, ZrO.5Ni, Zr-2.5Nb, Zircaloy-2 and the Excel Alloy have been electron irradiated at high temperatures, >675 K, with lMeV electrons to high fluences >2 dpa. The nature of the clustered point defects has been assessed and it has been shown that the oversized solute, Sn, significantly traps vacancies, and the undersized solute, Nb, significantly traps self-interstitial atoms, SIAs. In addition it has been proposed that the small, undersized solutes such as Fe, Cr and Ni in Zr undergo a replacement process with the SIAs, which decreases the mobility of the vacancies, enhancing recombination. It is thought that Ni has little influence on point defect behaviour in Zr due to its low solubility. The interstitial solute, oxygen, is argued to enhance the clustering of vacancies.