First-principles investigation of the interaction between oxygen and alloy atoms in [formula omitted]-zirconium

Abstract

Zirconium alloys, being crucial materials in the nuclear industry, frequently encounter issues related to oxidative corrosion. Understanding the interaction between O atom and alloying atoms at the atomistic scale is helpful for optimizing Zr alloys with improved corrosion resistance. In the present study, a first-principles approach is used to understand the stability and diffusion properties of an O atom in α-Zr with different alloy atoms (Sn, Nb, Fe and Cr). Our findings reveal that the most stable position for oxygen is always the octahedral (Oct) site whether it coordinates with an alloy atom or not. Comparing to other alloy atoms, Fe tends to exclude interstitial O even at the long range and the interaction is stronger than others, while the long-range interaction of Nb is the weakest. All alloy atoms considered in this work can enhance interstitial O diffusion rate, and promote the anisotropy of O diffusion. This work also confirms that the kinetically resolved activation method is a reliable method to predict the O diffusion barrier in α-Zr.