On Modeling the Evolution of Radiation Damage in Silicon Carbide
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1043-T02-05
On Modeling the Evolution of Radiation Damage in Silicon Carbide William J. Weber Pacific Northwest National Laboratory Richland, Washington USA
© 2008 Materials Research Society Contributors Fei Gao, Ram Devanathan, Yanwen Zhang, Weilin Jiang, Haiyan Xiao, In-Tae Bae and Zhouwen Rong November 26, 2007 Symposium T, MRS Fall Meeting Work supported by the Office of Basic Energy Sciences, US DOE Office of Science U.S. DEPARTMENT OF ENERGY
Pacific Northwest National Laboratory
Motivation Silicon Carbide (SiC) is a high-temperature semiconductor that is a promising material for a variety of nuclear, advanced electronic, sensor and structural applications ¾ Low neutron activation and relatively radiation hard ¾ Fission product barrier in pebble nuclear fuels (e.g., TRISO fuel) ¾ Core material in some prismatic nuclear core designs
© 2008 Materials Research Society
¾ Structural composite materials in HTGR and Fusion systems
¾ High Temperature, High Current, High Frequency electronic devices ¾ Solid State Sensors in harsh environments ¾ Neutron Detectors ¾ High-Temperature Structural Composites for harsh environments ¾ Biocompatible and has medical applications Pacific Northwest National Laboratory
Objective Develop fundamental understanding of defects, defect interactions and radiation effects to provide underpinning science and predictive models for technological advances in nuclear materials Goal is to integrate experimental & multi-scale computational methods to develop fundamental understanding and models related to: Defect production and damage accumulation mechanisms ©¾2008 Materials Research Society ¾ Defect migration processes and kinetics ¾ Recrystallization and phase changes ¾ Properties of radiation damage states Provides framework for modeling dynamic processes associated with the evolution of radiation damage as a function of time, temperature and dose. Pacific Northwest National Laboratory
Research Approach Materials Studied: 3C, 4H, & 6H SiC Single Crystals (wafers & films) Experimental ¾ 50 keV He+, 550 keV C+, 360 keV Ar+, 1.1 MeV Al22+, 550 keV Si+, 2 MeV Au2+ ¾ ¾ ¾ ¾ ¾
In Situ RBS and NRA Ion-Channeling High-Resolution TEM Irradiation (150 to 870 K) Thermal Annealing (150 to 870 K) Electron-Beam Irradiations
© 2008 Materials Research Society Multi-Scale Theoretical & Computer Simulations ¾ Ab Initio Calculations & Ab Initio Molecular Dynamics Defect Energies, Migration Barriers, Refinement of Potentials, Low-Energy Radiation Damage Processes
¾ Molecular Dynamics Collision Processes, Defect Migration, Annealing Processes
¾ Kinetic Monte Carlo Simulations Upscaling to macroscopic & longer time regimes Pacific Northwest National Laboratory
MD Results: Displacement Energy Surface for 3C-SiC Displacement Energy (eV)
140
3C-SiC
Ed(Si)
120
Ed(C)
[122] [0 7 10]
100
[025]
80
[188] [233]
[012]
60
40 Materials Research Society © 2008 [144]
20
[133]
[015]
0 [001]
[133] [233]
[011]
[111] [111]
[011]
Crystallographic Direction ¾ Anisotropic; Easier to displace C; Sim
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