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Interface pinning causes the hysteresis of the hydride transformation in binary metal hydrides
- Source :
- Physical Review Materials. 5
- Publication Year :
- 2021
- Publisher :
- American Physical Society (APS), 2021.
-
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.
- Subjects :
- Materials science
Physics and Astronomy (miscellaneous)
Hydride
Thermodynamics
02 engineering and technology
021001 nanoscience & nanotechnology
01 natural sciences
Nanocrystalline material
Condensed Matter::Materials Science
Hysteresis
Lattice constant
0103 physical sciences
Rectangular potential barrier
General Materials Science
Grain boundary
Solvus
010306 general physics
0210 nano-technology
Order of magnitude
Subjects
Details
- ISSN :
- 24759953
- Volume :
- 5
- Database :
- OpenAIRE
- Journal :
- Physical Review Materials
- Accession number :
- edsair.doi.dedup.....e73444367551d456fdadd459188dd7f1