Testing thermal gradient driving force for grain boundary migration using molecular dynamics simulations
- Idaho National Lab. (INL), Idaho Falls, ID (United States)
Strong thermal gradients in low-thermal-conductivity ceramics may drive extended defects, such as grain boundaries and voids, to migrate in preferential directions. In this work, molecular dynamics simulations are conducted to study thermal gradient driven grain boundary migration and to verify a previously proposed thermal gradient driving force equation, using uranium dioxide as a model system. It is found that a thermal gradient drives grain boundaries to migrate up the gradient and the migration velocity increases under a constant gradient owing to the increase in mobility with temperature. Different grain boundaries migrate at very different rates due to their different intrinsic mobilities. The extracted mobilities from the thermal gradient driven simulations are compared with those calculated from two other well-established methods and good agreement between the three different methods is found, demonstrating that the theoretical equation of the thermal gradient driving force is valid, although a correction of one input parameter should be made. The discrepancy in the grain boundary mobilities between modeling and experiments is also discussed.
- Research Organization:
- Energy Frontier Research Centers (EFRC) (United States). Center for Materials Science of Nuclear Fuel (CMSNF); Idaho National Laboratory (INL), Idaho Falls, ID (United States)
- Sponsoring Organization:
- USDOE Office of Nuclear Energy (NE)
- DOE Contract Number:
- AC07-05ID14517
- OSTI ID:
- 1177645
- Report Number(s):
- INL/JOU-14-32912; TRN: US1500184
- Journal Information:
- Acta Materialia, Vol. 85, Issue C; ISSN 1359-6454
- Publisher:
- Elsevier
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CRYSTAL DEFECTS
VELOCITY
VOIDS
GRAIN BOUNDARIES
MOLECULAR DYNAMICS METHOD
TEMPERATURE GRADIENTS
COMPUTERIZED SIMULATION
URANIUM DIOXIDE
MOBILITY
COMPARATIVE EVALUATIONS
EQUATIONS
TESTING
CERAMICS
CORRECTIONS
COMPUTER MODELING OF GRAIN BOUNDARTY MIGRATION IN U
GRAIN BOUNDARY MIGRATION
THERMAL GRADIENT DRIVING FORCE
MOLECULAR DYNAMICS
OXIDES