NSUF 16-837: Localized mechanical property assessment of neutron irradiated SiC/SiC composites at elevated temperature
In this proposal we investigate the effects of irradiation on the individual components of a silicon carbide matrix silicon carbide fiber reinforced (SiC/SiC) composite using nanoindentation to perform indents in the matrix and fiber separately. In addition to evaluating the effects of neutron irradiation the indentation will be performed at elevated temperature, up to 700 ºC, to evaluate the change in mechanical properties of individual components at temperature. The samples that the experiments will be performed on are from General Atomics and were irradiated in the high flux isotope reactor to 4.5 dpa at a temperature of 716 ºC. The ability to measure the mechanical properties of the individual components in the as fabricated conditionafter irradiation at temperature would greatly assist in modeling efforts of SiC/SiC composite materials. The data collected with these experiments will contribute in the development of multi-scale models of the composite behavior. This would be valuable since SiC/SiC composites are being considered as an accident tolerant cladding for water reactors, structural materials in Gen IV gas fast reactors, and the next generation of nuclear power reactors [1,2].
The methods to be employed in this research are high temperature nanoindentation. The instruments used to perform the nanoindentation at temperature will be the MicroMaterials indenter system location UC Berkeley facility. The instruments has an attached high power microscope that allows the accurate positioning of indents on the samples. The microscope allows the ability to locate fully infiltrated fibers in the matrix and have a field of indents place over them. The ability to place a field of indents over the fully infiltrated fiber gives the ability to measure both the fiber and matrix properties at the same time. In addition to the nanoindentation, the SEM/FIB instrument will be used to manufacture TEM foils from the indents at different temperatures to evaluate the microstructure in the deformed region. This would also allow a comparison of how the fibers and the matrix deform. In addition it gives a comparison of microstructure of matrix and fiber before and after irradiation. In addition part of the microstructural investigation would be to assess the effect of the displacement damage on the excess carbon in the fibers.
Both the irradiated and control sample would need to be polished which would take a week. The indentation of both samples would take a month. The manufacture of the TEM foils from the indents using the SEM/FIB system would also take roughly a 2-3 month. This would make the expected period of performance for these experiments approximately 3-5 months depending on machine time plus there would be additional time to analyze the data produced. This work is expected to be performed between January and June in 2017.
References:
[1] Snead, L.L. et al., "Handbook of SiC properties for fuel performance modeling," J. Nucl. Mater. 371, 329–377 (2007).
[2] Katoh, Y. et al.," Continuous SiC fiber, CVI SiC matrix composites for nuclear applications: Properties and irradiation effects," J. Nucl. Mater. 448, 448–476 (2014).
Additional Info
| Field | Value |
|---|---|
| Abstract | In this proposal we investigate the effects of irradiation on the individual components of a silicon carbide matrix silicon carbide fiber reinforced (SiC/SiC) composite using nanoindentation to perform indents in the matrix and fiber separately. In addition to evaluating the effects of neutron irradiation the indentation will be performed at elevated temperature, up to 700 ºC, to evaluate the change in mechanical properties of individual components at temperature. The samples that the experiments will be performed on are from General Atomics and were irradiated in the high flux isotope reactor to 4.5 dpa at a temperature of 716 ºC. The ability to measure the mechanical properties of the individual components in the as fabricated conditionafter irradiation at temperature would greatly assist in modeling efforts of SiC/SiC composite materials. The data collected with these experiments will contribute in the development of multi-scale models of the composite behavior. This would be valuable since SiC/SiC composites are being considered as an accident tolerant cladding for water reactors, structural materials in Gen IV gas fast reactors, and the next generation of nuclear power reactors [1,2]. The methods to be employed in this research are high temperature nanoindentation. The instruments used to perform the nanoindentation at temperature will be the MicroMaterials indenter system location UC Berkeley facility. The instruments has an attached high power microscope that allows the accurate positioning of indents on the samples. The microscope allows the ability to locate fully infiltrated fibers in the matrix and have a field of indents place over them. The ability to place a field of indents over the fully infiltrated fiber gives the ability to measure both the fiber and matrix properties at the same time. In addition to the nanoindentation, the SEM/FIB instrument will be used to manufacture TEM foils from the indents at different temperatures to evaluate the microstructure in the deformed region. This would also allow a comparison of how the fibers and the matrix deform. In addition it gives a comparison of microstructure of matrix and fiber before and after irradiation. In addition part of the microstructural investigation would be to assess the effect of the displacement damage on the excess carbon in the fibers. Both the irradiated and control sample would need to be polished which would take a week. The indentation of both samples would take a month. The manufacture of the TEM foils from the indents using the SEM/FIB system would also take roughly a 2-3 month. This would make the expected period of performance for these experiments approximately 3-5 months depending on machine time plus there would be additional time to analyze the data produced. This work is expected to be performed between January and June in 2017. References: [1] Snead, L.L. et al., "Handbook of SiC properties for fuel performance modeling," J. Nucl. Mater. 371, 329–377 (2007). [2] Katoh, Y. et al.," Continuous SiC fiber, CVI SiC matrix composites for nuclear applications: Properties and irradiation effects," J. Nucl. Mater. 448, 448–476 (2014). |
| Award Announced Date | 2016-12-16T07:47:35.15 |
| Awarded Institution | None |
| Facility | None |
| Facility Tech Lead | Peter Hosemann |
| Irradiation Facility | None |
| PI | David Frazer |
| PI Email | [email protected] |
| Project Type | RTE |
| RTE Number | 837 |