Chapter 75. Confirmation of Unload/Reload Tensile Tests for Determining Constituent Properties and Performance in an Oxide-Oxide CFCC

Summary

Oxide fiber-reinforced / oxide matrix CFCCs have the potential of resisting the high-temperature degradation of these materials 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 lack of information on the in-situ properties and performance of the composite's constituents (i.e., fibers, interphase, matrix). Phenomenological and analytical evaluations of unload/reload tensile test results (i.e. hysteretic stress-strain response) were used to extract information on residual stress state, interfacial shear stress, and other constituent behaviour in an alumina (Nextel) fiber-reinforced / porous alumina matrix. Photostimulate luminescence and fiber push-out testing were used to confirm the phenomenological and analytical evaluations of residual stress state and interfacial shear stress.