First Principle Calculations Of Electronic Structure For Zr-Nb

Zr alloy has been widely used in the nuclear industry because of its excellent corrosion resistance,oxidation resistance,low thermal neutron absorption cross-sectional area,and high mechanical properties.Nb has good thermal conductivity,high melting point and strong corrosion resistance and other characteristics,is a very important alloying elements,Nb as zirconium alloy alloying elements,zirconium alloy can produce a small amount of harmful impurities to a certain clearance effect,improve the corrosion resistance of zirconium alloy,and can reduce the amount of hydrogen absorption of zirconium alloy,so Nb is very suitable for nuclear reactor alloy material.To add to the zirconium alloys of different concentrations of Nb and placeholder,study the effect of the corrosion mechanism,and research and development of new type Zr-Nb alloy,simulation results of new zirconium niobium alloy material performance on microscopic and deep understanding on all areas of wide application and popularization has great contribution and significance of reference.In this paper,we use the VSAP software package based on the first principle of density functional theory to calculate the binding energy and electronic structure of different unit cell sizes of Zr and Nb.Then,the Zr-Nb binary alloy The crystal structure and the electronic structure of Zr and Nb crystals were calculated.The main conclusions are as follows:(1)Before calculating the crystal structure and electronic structure of Zr-Nb binary alloy at different concentrations and occupies of Nb,2×2×2 supercells and3×3 ×3 supercells of Zr crystal were calculated,respectively,and Nb crystal of the unit cells and 2×2×2 supercell lattice constant and binding energy,the calculated results in line with the experimental value is very good.The metal density of Zr and Nb was verified by using the calculated results.(2)The stability of Zr-Nb alloy: The lattice constant of Zr-Nb alloy tends to decrease with the increase of Nb content.The Zr14Nb2-(3),Zr13Nb3-(1),Zr12Nb4-(3),Zr52Nb2-(2),Zr51Nb3-(4),Zr50Nb4-(5)are the most stable,the Nb element in Zr-Nb alloy tends to aggregate distribution;Zr-Nb alloy electronic structure: the Zr-Nb alloy conduction band,valence band and Fermi level at the electronic structure is mainly from the Zr d-track and Nb d-track electrons at the same time;corrosion resistance of the strongest configuration Zr14Nb2-(3),Zr13Nb3-(3),Zr12Nb4-(1),Zr52Nb2-(2),Zr51Nb3-(4)and Zr50Nb4-(7).(3)When Nb impurity is doped into Zr crystal,the two atoms are attracted to each other,indicating that Nb impurities in Zr crystals tend to accumulate.When Zr impurity is doped into Nb crystal,two atoms show the attraction for each other,which increases first and then decreases as the distance increases,and the difference in the interaction is not obvious from the magnitude of the interaction energy.