FIGURE 17 A schematic illustrating the stress oxidation effect. Oxygen penetrates the material through the matrix cracks. Local oxidation interacts with the stress concentrations on the fibers to diminish their failure strength, causing the fibers to fail at the matrix crack. This process repeats, and the crack extends in a manner analogous to stress corrosion. SOURCE: Reprinted (modified) from Evans et al. (1997) , with permission from the American Ceramic Society.