| About this Abstract |
| Meeting |
Materials Science & Technology 2020
|
| Symposium
|
Ceramic Matrix Composites
|
| Presentation Title |
Characterizing Environment-dependent Fracture Mechanisms of SiC-SiC CMCs via Novel Four-point Bend / Hermeticity Test Frame |
| Author(s) |
Clifton Bumgardner, Frederick Heim, David Roache, Xiaodong Li |
| On-Site Speaker (Planned) |
Clifton Bumgardner |
| Abstract Scope |
Using a novel four-point bend / hermeticity test frame, we investigate the coupled failure mechanisms and gas-tightness properties of SiC/SiC ceramic matrix composites (CMCs) exposed to high temperature environments up to 1400°C in oxidizing and inert environments. Multiple-perspective, three-dimensional digital image correlation quantified in-situ deformation and strain; the strain maps were refined to track individual crack growth. Internal CMC degradation was characterized via X-ray tomography while the environmental impact on the CMC was characterized via X-ray diffraction and energy-dispersive X-ray spectroscopy. Crack opening displacement was correlated directly with leak rate and acoustic activity, thus identifying critical thresholds for loss of gas tightness, through-thickness matrix cracking, and fiber pullout for CMCs exposed to different harsh environments. This testing identified distinct deformation thresholds leading to ultimate failure, which may be used to govern the safe use of SiC/SiC CMCs in aerospace and nuclear energy applications. |