Defect production and segregation induced by collision cascades in U-10Zr alloy

Abstract

Swelling and constituent redistribution of uranium-zirconium (U-Zr) alloys under irradiation will hinder their further application as feasible nuclear fuels. It is necessary to explore the primary irradiation damage induced by collision cascades in U-Zr alloys due to its profound effect on subsequent swelling and constituent redistribution. Herein, we perform molecular dynamic simulations to investigate the irradiation characteristic in the collision cascade of U-10Zr (U with 10 wt% Zr). It is found that, compared with pure U, the addition of Zr can reduce the peak number and increase the surviving number of Frenkel pairs, which should be attributed to the huge atomic mass difference between U and Zr. In U-10Zr alloy, the formation of Zr interstitials is found to be suppressed by analyzing the solute interstitial production efficiency, which is caused by the higher formation energy of Zr interstitials than that of U interstitials in a U matrix. Our simulations also indicate that the solute separation phenomenon actually happens in the collision cascade of U-10Zr. In addition, secondary peaks appear in the curves of defect number, which is induced by the interaction between shock waves and periodic boundaries. The present simulation data and insights would be significant for understanding the irradiation damage behavior of U-Zr alloy in collision cascades.