Abstract
A fracture mechanics specimen shaped as a single-edge double-notched beam (SEDNB), was specially designed for evaluating the fracture properties of brittle ceramic materials. The notch-tip was sharpened to a radius <10μm in order to reduce the amount of elastic energy stored at its root prior to crack extension. Furthermore, a crack stabilizer, designed for the bending geometry, was employed. The use of this special stabilizer as well as a new machining technique developed for introducing the sharp notches made it possible the detectability of near-tip R-curve behavior, and to discern it from long-crack R-curve behavior. As an application of this technique, the R-curve behavior of Al2O3/ZrO2 (2.5Y-TZP) composites has been evaluated and the micromechanism responsible for such a behavior theoretically discussed.
