Date of Award


Document Type


Degree Name

Master of Science


Department of Aeronautics and Astronautics

First Advisor

Marina B. Ruggles-Wrenn, PhD


The tension-tension fatigue behavior of two oxide-oxide ceramic matrix composites (CMCs) was investigated at 1200°C in laboratory air and steam. Both composites consist of a porous oxide matrix reinforced with laminated, woven mullite/alumina (NextelTM720) fibers. The first composite had an alumina matrix, while the second had an alumina-mullite matrix. First, we assessed the effects of incorporating mullite into the matrix material on fatigue performance by studying the tension-tension fatigue behavior of alumina-mullite matrix CMC. Second, we evaluated the effects of effusion holes on the alumina matrix CMC's fatigue performance. Specimens containing an array of 17 effusion holes of 0.5-mm diameter were tested in tension-tension fatigue. The fatigue run-out was set to 100,000 cycles. All specimens that achieved fatigue run-out were subjected to tension tests to failure in order to measure the retained tensile properties. Fracture surfaces of the tested specimens were examined, damage and failure mechanisms are discussed.

AFIT Designator


DTIC Accession Number