Layer orientation effects on the R-curve behavior of multilayered alumina–zirconia composites

The crack growth resistance (R-curve) behavior of multilayered alumina–zirconia composites was measured using a single-edge-V-notched-beam (SEVNB) testing method in which crack initiation and extension were observed via in situ optical microscopy. The influence of the relative layer orientation with respect to the crack-tip front through the composite on the resulting R-curves were measured and was found to have a pronounced influence on the measured crack growth resistance behavior. By increasing the layer offset, the specific influence of a given feature within the layered structure on the measured R-curve behavior was found to diminish.