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Title: Homogeneous hydride formation path in α-Zr: Molecular dynamics simulations with the charge-optimized many-body potential

A formation path for homogeneous γ hydride formation in hcp α-Zr, from solid solution to the ζ and then the γ hydride, was demonstrated using molecular static calculations and molecular dynamic simulations with the charge-optimized many-body (COMB) potential. Hydrogen has limited solubility in α-Zr. Once the solubility limit is exceeded, the stability of solid solution gives way to that of coherent hydride phases such as the ζ hydride by planar precipitation of hydrogen. At finite temperatures, the ζ hydride goes through a partial hcp-fcc transformation via 1/3 <1¯100> slip on the basal plane, and transforms into a mixture of γ hydride and α-Zr. In the ζ hydride, slip on the basal plane is favored thermodynamically with negligible barrier, and is therefore feasible at finite temperatures without mechanical loading. The transformation process involves slips of three equivalent shear partials, in contrast to that proposed in the literature where only a single shear partial was involved. The adoption of multiple slip partials minimizes the macroscopic shape change of embedded hydride clusters and the shear strain accumulation in the matrix, and thus reduces the overall barrier needed for homogeneous γ hydride formation. In conclusion, this formation path requires finite temperatures for hydrogen diffusionmore » without mechanical loading. Therefore, it should be effective at the cladding operating conditions.« less
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Publication Date:
Report Number(s):
Journal ID: ISSN 1359-6454; PII: S1359645416302555
Grant/Contract Number:
AC07-05ID14517; 14-026
Accepted Manuscript
Journal Name:
Acta Materialia
Additional Journal Information:
Journal Volume: 111; Journal Issue: C; Journal ID: ISSN 1359-6454
Research Org:
Idaho National Lab. (INL), Idaho Falls, ID (United States)
Sponsoring Org:
Country of Publication:
United States
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS; 36 MATERIALS SCIENCE; zirconium; hydride; molecular dynamics
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1357668