Effects of Oxygen on the Density of States and Elastic Properties of Hafnium—First Principles Calculations

摘要

Due to its excellent comprehensive properties, Hf has been the preferred material for control rods in the nuclear reactors. There is a very strong influence of even small additions of oxygen element on the mechanical properties of Hf alloy. This work we report results of first-principles calculations of structure stability, density of states and elastic properties including the full set of second order elastic coefficients, bulk moduli and shear moduli, Young's moduli, and Poisson's ratio of Hf as a function of positions and concentration of oxygen atoms. Oxygen atom prefers to occupy octahedral and hexahedral interstitial sites due to the lower formation energy and less lattice distortion. Oxygen content has very weak influence on the density of states. The effects of oxygen content on the elastic parameters were estimated with the conclusion that approximately high oxygen addition decreased elastic and plastic properties.