When 2:00 PM - 3:00 PM May 28, 2020
Where Virtual
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PhD Defense: “Damage Evolution and Characterization of SiC/SiC Ceramic Matrix Composites using Micro-Computed Tomography Techniques”

Ashley Hilmas
Halloran Group

Ceramic matrix composites are of importance within the aerospace industry because of their unique high temperature capability and improved toughness when compared to traditional ceramics. However, because of their complicated microstructure it is important to better understand how damage evolves in these materials under mechanical loading. The three main types of damage in these materials are matrix cracking, fiber fragmentations, and debonding along the fiber/matrix interface. X-ray computed tomography can be utilized as a method to study these composite materials in order to better understand their mechanical properties. In this study, melt-infiltrated (MI) HiPerCompTM SiC/SiC ceramic matrix composites (CMCs) were characterized through the use of synchrotron x-ray tomography at the Advanced Light Source (ALS) at Lawrence Berkeley National Laboratory. Both unidirectional and cross-ply [0o/90o]s SiC/SiC CMC specimens were imaged under increasing tensile loading and damage progression such as matrix crack spacing and the openings of fiber fragmentations were quantified. The various types of damage such as matrix cracking and fiber fragmentations were correlated to each other based on their locations within the volume of the specimen and the damage observed at each stress increment was then compared to well-known mechanical models.

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