Measuring interphase recession by fiber push-in testing

A novel technique for measuring interphase recession in ceramic-matrix comp osites (CMCs) due to oxidation is described, The technique involves fiber p ush-in testing and analysis of the load-displacement curves. Fiber push-in tests were conducted on carbon-coated Hi-Nicalon SiC fibers in a CVI SiC ma trix, where the carbon interphase had recessed due to oxidation, Estimates of interphase recession distances from analysis of fiber push-in tests are in reasonable agreement with measurements made by optical microscopy, Besid es measuring the recession distance, the fiber push-in test can be used to investigate environmental effects on fiber bridging.