Determination of mechanical behavior of U3Si2 nuclear fuel by microindentation method. (August 2017)

• Record Type: Journal Article
• Authors: Metzger, Kathryn E.; Knight, Travis W.; Roberts, Elwyn; Huang, Xinyu
• Is Part Of: Progress in nuclear energy. Volume 99(2017:Aug.)
• Page Start: 147
• Page End: 154
• Publication Date: 2017-08
• Subjects: Advanced nuclear fuel -- Uranium silicide -- Vickers microindentation -- Fracture toughness -- Hardness; Nuclear energy -- Periodicals; Nuclear engineering -- Periodicals; 333.7924
• DOI: 10.1016/j.pnucene.2017.05.007
• Languages: English
• ISSNs: 0149-1970

Abstract

Abstract: Purpose: U3 Si2 is under investigation as an accident tolerant fuel due to its advantageous thermo-physical properties, including; high uranium density, high thermal conductivity, and high melting temperature. However, mechanical data available for the fuel is limited. Vickers micro-indentation characterization was used to evaluate the mechanical properties of U3 Si2 specimens of varying microstructure in order to determine the effect of sintering conditions on mechanical behavior. Methods: A chemical etchant was applied in order to observe grain boundaries in the material. The microstructure surrounding the indentations was investigated using polarized light optical microscopy imaging, scanning electron microscopy imaging, and elemental analysis techniques. Results: All U3 Si2 samples cracked in a brittle manner with cracks adjacent to the indents. Cracks tend to propagate through grains rather than along grain boundaries. The Vickers hardness of the U3 Si2 samples was between 414 HV and 678 HV. High porosity in the sample was associated with a lower hardness. The toughness of the samples was roughly the same amongst all U3 Si2 samples, ∼1 MPa√m. Conclusions: The hardness and fracture toughness of U3 Si2 was found to be comparable to that of unirradiated UO2 . Given that UO2 has a history of good experience in the nuclear industry, U3 Si2 's comparable cracking behavior and mechanical properties speak favorably for its anticipated performance in reactor.