Interactions between interstitial oxygen and substitutional niobium atoms in Ti–Nb–O BCC alloys: First-principles calculations

Chenguang Liu,Chenxi Liu,Zongqing Ma,Yongchang Liu,Huijun Li,Chong Li,Liming Yu

doi:10.1063/1.5125713

Abstract

In this paper, the interactions between interstitial oxygen atoms and substitutional atoms in Ti–Nb–O alloys were investigated by first-principles calculations based on the density functional theory. The binding energies and formation energies of oxygen atoms sited were calculated in various interstices with different geometries, element species, and atomic arrangements. The calculation results showed that there was a strong repulsive binding energy between the interstitial oxygen and the substitutional niobium atoms. On this basis, the energetically favored sites and the distribution of interstitial oxygen atoms in Ti–Nb–O alloys were discussed and demonstrated by an electron energy loss spectroscopy method. Furthermore, the diffusion activation energies of interstitial oxygen atoms based on the formation energy results were presented, and the diffusion behaviors of interstitial oxygen atoms in Ti–Nb–O alloys were also discussed.

Highlights

The interaction of interstitial atoms with substitutional atoms is indispensable information for understanding many basic physical performances and applications of solid solutions
The main purpose of this paper is to clarify the behaviors of interstitial oxygen atoms interacting with substitutional atoms in ternary Ti–Nb–O alloys in detail through calculating binding energies, formation energies, and diffusion activation energies by firstprinciples calculations based on density functional theory (DFT)
Different configurations δu-v can be distinguished by the number and arrangement of substitutional sites (u is the number of substitutional atoms from 0 to 6, and v represents the different configurations of substitutional atoms)

Summary

Introduction

The interaction of interstitial atoms with substitutional atoms is indispensable information for understanding many basic physical performances and applications of solid solutions. A typical example is the development of the so-called Snoek-type high-damping ternary alloys (such as Ti–Nb–O,1 Nb–V–O,2 etc.) That is why these alloys usually exhibit high-damping performance. It is essential to investigate the basic physical properties of interstitial atoms, including their interactions with substitutional atoms, their energy situations, and their diffusion activation energies in these alloy systems

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Results

Conclusion