Trapping of interstitial defects: filling the gap between the experimental measurements and DFT calculations

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	Trapping of interstitial defects: filling the gap between the experimental measurements and DFT calculations
	L. G. Zhu; H. Wang; Q. M. Hu; G. J. Ackland; R. Yang
	2013
发表期刊	Journal of Physics-Condensed Matter
ISSN	0953-8984
卷号	25 期号:43
摘要	We show that any impurity will slow the diffusion of oxygen in Nb. Using a first-principles plane-wave pseudopotential method and the supercell model, we calculated the interaction energies between substitutional atoms (SA) (X = Ti, V, Ta, Zr, and Hf) and interstitial oxygen in a Nb matrix. All impurities act as traps for oxygen: undersized SA (Ti and V) have strongest binding at the nearest octahedral interstice, while for oversized SA (Zr and Hf), the strongest trapping site is the second-nearest octahedral interstice. We evaluated the diffusion coefficients of O in the Nb-X alloys using kinetic Monte Carlo (KMC) modeling based in the transition state theory, using our calculated oxygen migration energies. From this, the effective (average) X-O interaction energies were extracted using the Oriani model (Oriani 1970 Acta Metall. 18 147-57). The effective X-O interaction energies are close to the strongest interaction energies between X and O obtained from the direct supercell calculations. The phenomenological effective diffusion barrier obtained from the KMC modeling is close to the energy difference between the most stable configuration and the highest saddle point along the diffusion path. Both results demonstrate that the weaker trapping site has negligible influence on the diffusion of O.
部门归属	[zhu, linggang ; wang, hao ; hu, qing-miao ; yang, rui] chinese acad sci, shenyang natl lab mat sci, inst met res, shenyang 110016, peoples r china. [ackland, graeme j.] univ edinburgh, sch phys & astron, supa, edinburgh eh9 3jz, midlothian, scotland. ; zhu, lg (reprint author), chinese acad sci, shenyang natl lab mat sci, inst met res, shenyang 110016, peoples r china. ; qmhu@imr.ac.cn
关键词	Solid-solutions Diffusion Oxygen Niobium Hydrogen Alloys Metals Energy Oxidation Titanium
URL	查看原文
语种	英语
文献类型	期刊论文
条目标识符	http://ir.imr.ac.cn/handle/321006/71745
专题	中国科学院金属研究所
推荐引用方式 GB/T 7714	L. G. Zhu,H. Wang,Q. M. Hu,et al. Trapping of interstitial defects: filling the gap between the experimental measurements and DFT calculations[J]. Journal of Physics-Condensed Matter,2013,25(43).
APA	L. G. Zhu,H. Wang,Q. M. Hu,G. J. Ackland,&R. Yang.(2013).Trapping of interstitial defects: filling the gap between the experimental measurements and DFT calculations.Journal of Physics-Condensed Matter,25(43).
MLA	L. G. Zhu,et al."Trapping of interstitial defects: filling the gap between the experimental measurements and DFT calculations".Journal of Physics-Condensed Matter 25.43(2013).