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Interface pinning causes the hysteresis of the hydride transformation in binary metal hydrides

Weadock, Nicholas J. and Voorhees, Peter W. and Fultz, Brent (2021) Interface pinning causes the hysteresis of the hydride transformation in binary metal hydrides. Physical Review Materials, 5 (1). Art. No. 013604. ISSN 2475-9953. https://resolver.caltech.edu/CaltechAUTHORS:20210128-095301970

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Abstract

Hydriding and dehydriding transitions in bulk and nanocrystalline binary metal hydrides were studied using the Pd-H model system by measuring pressure-composition isotherms with in situ x-ray diffractometry. Nanocrystalline Pd showed a smaller pressure hysteresis, solvus hysteresis, and hysteresis in lattice parameter, compared to bulk Pd. The time-dependence of pressure equilibration was measured after dosing with aliquots of hydrogen, giving equilibration times that were much faster in the single-phase regions than in the two-phase plateaus. In the broad two-phase plateaus, the pressure relaxations were exponential functions of time. An explanation of hysteresis is developed that is based on a dissipative potential barrier that impedes the motion of the interface due to interactions between lattice defects and the two-phase interface. The exponential pressure relaxations and hysteresis are consistent for this mechanism. For a simple model of the pinning potential, the potential barrier maximum is an order of magnitude less than typical grain boundary energies. These pinning effects are substantially different in the nanocrystalline Pd, suggesting differences in the hydriding mechanism.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1103/PhysRevMaterials.5.013604DOIArticle
ORCID:
AuthorORCID
Weadock, Nicholas J.0000-0002-1178-7641
Voorhees, Peter W.0000-0003-2769-392X
Fultz, Brent0000-0002-6364-8782
Additional Information:© 2021 American Physical Society. Received 10 September 2020; accepted 8 January 2021; published 28 January 2021. The authors acknowledge A. Moorthy for assistance with experimental data collection and helpful discussion. We gratefully acknowledge the critical support and infrastructure provided for this work by the Kavli Nanoscience Institute at Caltech. This work was supported by the National Science Foundation under Grant No. 1904714. P.W.V. is grateful for financial support received as a Moore Distinguished Scholar at Caltech. We gratefully acknowledge the critical support and infrastructure provided for this work by The Kavli Nanoscience Institute at Caltech.
Group:Kavli Nanoscience Institute
Funders:
Funding AgencyGrant Number
NSFDMR-1904714
Gordon and Betty Moore FoundationUNSPECIFIED
Kavli Nanoscience InstituteUNSPECIFIED
Issue or Number:1
Record Number:CaltechAUTHORS:20210128-095301970
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20210128-095301970
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:107783
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:28 Jan 2021 18:06
Last Modified:28 Jan 2021 18:06

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