SYMPOSIA PAPER Published: 01 January 2000

Use of Unload/Reload Methodologies to Investigate the Thermal Degradation of an Alumina Fiber-Reinforced Ceramic Matrix Composite


Oxide fiber-reinforced/oxide matrix continuous fiber-reinforced ceramic composites (CFCCs) have the potential of resisting high-temperature degradation in the increasingly aggressive environments of the emerging applications of this still-evolving class of materials. However, a major design and processing limitation of CFCCs is the lack of information on the in situ properties and performance of the composite constituents (i.e., fibers, interphase, and matrix). Monotonic and unload/reload tensile tests were conducted in ambient air on CFCC test specimens in the unexposed condition and after 10- and 100-h exposures at 600, 800, 1000 and 1200°C. Two methodologies were used for the evaluation of the unload/reload tensile test results to extract constitutive property data on the residual stress state, interfacial shear stress, interfacial debond resistance, and damage state of the composite. The phenomenological approach is based on the stiffness degradation of the composite with incremental load steps. The analytical approach is based on the shape of the unload/reload hysteresis loops.

Author Information

Campbell, CX
Siemens Westinghouse Power Corporation, Orlando, FL
Jenkins, MG
University of Washington, Seattle, WA
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Developed by Committee: C28
Pages: 118–133
DOI: 10.1520/STP15009S
ISBN-EB: 978-0-8031-5440-7
ISBN-13: 978-0-8031-2872-9