|About this Abstract
||Materials Science & Technology 2019
||Materials for Nuclear Applications
||Unveiling SiC/SiC CMC Cladding Failure Mechanisms and Hermetic Performance with In-situ 3D-Digital Image Correlation
||Clifton Bumgardner, Frederick M Heim, Xiaodong Li
|On-Site Speaker (Planned)
We unveil a custom four-point bend, hermeticity test rig for evaluation of the coupled mechanical and hermeticity performance of SiC/SiC CMC nuclear fuel claddings. This rig integrates in-situ digital image correlation, acoustic emission monitoring, and leak detection to develop an in-process understanding of crack initiation and propagation, leading to loss of hermeticity under load. These tests have illustrated that loss of hermeticity begins after the onset of matrix microcracking, indicating hermeticity is dependent on matrix properties. In-situ XCT expanding plug testing also elucidate fracture mechanisms and interactions between fracture and CMC microstructure, indicating a limited degree of matrix porosity may help arrest crack propagation and delay loss of hermeticity. These insights are expected to inform manufacturing of CMC claddings for optimal performance in reactor environments and will provide key inputs for fracture mechanics models under development for CMCs, including strain distribution along individual tows and local strain concentrations driving fracture.