NSUF 16-652: Wigner Energy of SiC Irradiated to High Levels of Swelling

Recently, through an FCRD sponsored research effort, single crystal alpha and beta SiC as well as faulted beta (CVD SiC) were irradiated over a range of fluences in the HFIR at ~ 80°C. The purpose of that study was to determine whether there was an intrinsic difference in swelling, such as anisotropy, between the SiC crystal types. Findings of that paper were recently published. Beyond the central finding of that paper, that there is no difference in swelling between the cubic and hexagonal crystal structures, the authors noted an extraordinary level of swelling (~7.8%) prior to amorphization, at which point the crystal underwent ~11.8% swelling. At the high 7.8% swelling level both X-ray and high resolution TEM indicated that the material was still fully crystalline. Given the swelling levels of the current samples are several times that of the Primak work it is very plausible that the stored energy release will exceed the specific heat. The focus of this proposal is to utilize the irradiated CVD SiC specimens at each fluence level of the previous work (0.02 to 20 dpa) and carry out scanning calorimetry to determine the stored energy release. Samples are currently in the LAMDA laboratory at the Oak Ridge National Laboratory. The specific designation of the samples are: PC-1-M1 (the 0.02 dpa), PC-2-M2, PC-3-M3, PC-4-M4, and PC-5-M5 samples. The procedure for carrying out the work will be the sectioning of the sample to procure an appropriate mass of irradiated SiC, to wash the sample in hydrofluoric acid, and to measure the energy release using the TA Instruments Q600 Simultaneous Differential Scanning Calorimeter and Thermogravimetris Analyzer. Scan will be from room temperature to 1500°C. In addition to the irradiated samples a non-irradiated control sample will be used. It is anticipated that the duration of the testing will be less than six months.

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필드	값
Abstract	Recently, through an FCRD sponsored research effort, single crystal alpha and beta SiC as well as faulted beta (CVD SiC) were irradiated over a range of fluences in the HFIR at ~ 80°C. The purpose of that study was to determine whether there was an intrinsic difference in swelling, such as anisotropy, between the SiC crystal types. Findings of that paper were recently published. Beyond the central finding of that paper, that there is no difference in swelling between the cubic and hexagonal crystal structures, the authors noted an extraordinary level of swelling (~7.8%) prior to amorphization, at which point the crystal underwent ~11.8% swelling. At the high 7.8% swelling level both X-ray and high resolution TEM indicated that the material was still fully crystalline. Given the swelling levels of the current samples are several times that of the Primak work it is very plausible that the stored energy release will exceed the specific heat. The focus of this proposal is to utilize the irradiated CVD SiC specimens at each fluence level of the previous work (0.02 to 20 dpa) and carry out scanning calorimetry to determine the stored energy release. Samples are currently in the LAMDA laboratory at the Oak Ridge National Laboratory. The specific designation of the samples are: PC-1-M1 (the 0.02 dpa), PC-2-M2, PC-3-M3, PC-4-M4, and PC-5-M5 samples. The procedure for carrying out the work will be the sectioning of the sample to procure an appropriate mass of irradiated SiC, to wash the sample in hydrofluoric acid, and to measure the energy release using the TA Instruments Q600 Simultaneous Differential Scanning Calorimeter and Thermogravimetris Analyzer. Scan will be from room temperature to 1500°C. In addition to the irradiated samples a non-irradiated control sample will be used. It is anticipated that the duration of the testing will be less than six months.
Award Announced Date	2016-04-11T00:00:00
Awarded Institution	None
Facility	None
Facility Tech Lead	Kory Linton
Irradiation Facility	None
PI	Lance Snead
PI Email	[email protected]
Project Type	RTE
RTE Number	652