Firstprinciples calculations of solute transport in zirconium: Vacancymediated diffusion with metastable states and interstitial diffusion
Abstract
Zirconium alloys are the most widely used nuclear fuel cladding materials for light water power reactors where irradiation damage causes solute redistribution, leading to degradation of alloy properties such as corrosion resistance. Designing radiationtolerant zirconium alloys requires a thorough understanding of the atomicscale transport behavior of the alloying elements in Zr. We perform density function theory calculations to investigate the diffusion of Sn, Cr, Fe, Be, Al, and Ni in the hexagonal closepacked (HCP) Zr matrix. We develop a methodology to accurately model the metastable vacancy states along the basal migration path, known to occur in group IV metals. We compute the vacancymediated solute diffusion coefficients and drag ratios using the kinetic Monte Carlo method and an analytic Green's function method—the agreement between the two validates our methodology. The computed diffusion coefficients of Sn and Al show good agreement with the experimental data and we expect these solutes to diffuse via the vacancymediated mechanism. We use a Green's function approach, parameterized with data from density functional theory calculations, to compute the interstitial diffusion coefficients of Cr, Fe, Be, and Ni in the HCP Zr lattice. The computed diffusion coefficients of Cr, Ni, and Be agree with the experimental measurements withinmore »
 Authors:

 Univ. of Illinois, UrbanaChampaign, IL (United States). Dept. of Materials Science and Engineering
 Univ. of New South Wales, Sydney, NSW (Australia). School of Mechanical and Manufacturing Engineering; Imperial College London, London (United Kingdom). Materials Dept.
 Publication Date:
 Research Org.:
 Lawrence Berkeley National LaboratoryNational Energy Research Scientific Computing Center (NERSC)
 Sponsoring Org.:
 USDOE
 OSTI Identifier:
 1530403
 Resource Type:
 Journal Article
 Journal Name:
 Physical Review Materials
 Additional Journal Information:
 Journal Volume: 3; Journal Issue: 3; Journal ID: ISSN 24759953
 Country of Publication:
 United States
 Language:
 English
Citation Formats
Jain, Abhinav C. P., Burr, Patrick A., and Trinkle, Dallas R. Firstprinciples calculations of solute transport in zirconium: Vacancymediated diffusion with metastable states and interstitial diffusion. United States: N. p., 2019.
Web. doi:10.1103/PhysRevMaterials.3.033402.
Jain, Abhinav C. P., Burr, Patrick A., & Trinkle, Dallas R. Firstprinciples calculations of solute transport in zirconium: Vacancymediated diffusion with metastable states and interstitial diffusion. United States. doi:10.1103/PhysRevMaterials.3.033402.
Jain, Abhinav C. P., Burr, Patrick A., and Trinkle, Dallas R. Fri .
"Firstprinciples calculations of solute transport in zirconium: Vacancymediated diffusion with metastable states and interstitial diffusion". United States. doi:10.1103/PhysRevMaterials.3.033402.
@article{osti_1530403,
title = {Firstprinciples calculations of solute transport in zirconium: Vacancymediated diffusion with metastable states and interstitial diffusion},
author = {Jain, Abhinav C. P. and Burr, Patrick A. and Trinkle, Dallas R.},
abstractNote = {Zirconium alloys are the most widely used nuclear fuel cladding materials for light water power reactors where irradiation damage causes solute redistribution, leading to degradation of alloy properties such as corrosion resistance. Designing radiationtolerant zirconium alloys requires a thorough understanding of the atomicscale transport behavior of the alloying elements in Zr. We perform density function theory calculations to investigate the diffusion of Sn, Cr, Fe, Be, Al, and Ni in the hexagonal closepacked (HCP) Zr matrix. We develop a methodology to accurately model the metastable vacancy states along the basal migration path, known to occur in group IV metals. We compute the vacancymediated solute diffusion coefficients and drag ratios using the kinetic Monte Carlo method and an analytic Green's function method—the agreement between the two validates our methodology. The computed diffusion coefficients of Sn and Al show good agreement with the experimental data and we expect these solutes to diffuse via the vacancymediated mechanism. We use a Green's function approach, parameterized with data from density functional theory calculations, to compute the interstitial diffusion coefficients of Cr, Fe, Be, and Ni in the HCP Zr lattice. The computed diffusion coefficients of Cr, Ni, and Be agree with the experimental measurements within one order of magnitude, while those of Fe are within two orders of magnitude of the experimental measurements. The drag ratios for Cr, Fe, Be, and Ni are positive up to 1235 K, which suggests that nonequilibrium vacancy fluxes could drag these solutes toward sinks such as dislocation loops and grain boundaries. We also compute the transport coefficients without including the metastable states, and using the eight and thirteenfrequency model. Our results show significant differences in drag ratio for the eight and thirteenfrequency model predictions compared with the Green's function methodology, but smaller errors in the solute diffusivity. Combining interstitial and vacancymediated diffusivities, we predict the unusual result that increased vacancy concentration slows down solute diffusivity, while a sufficiently high vacancy concentration can change the dominant mechanism to an accelerated vacancymediated diffusion.},
doi = {10.1103/PhysRevMaterials.3.033402},
journal = {Physical Review Materials},
issn = {24759953},
number = 3,
volume = 3,
place = {United States},
year = {2019},
month = {3}
}