R-curve behavior in alumina–zirconia composites with repeating graded layers

The single-edge-V-notched-beam testing geometry was used to measure the crack growth resistance (R-curve) behavior of multilayer graded alumina–zirconia composites for crack extensions parallel to the graded direction. Fracture mechanics weight function analysis was applied to explain the R-curve behavior of a compositional and grain-size graded microstructure. The results were then used to differentiate the influence of residual stress from other closure stresses, attributed to crack bridging, on the measured R-curve behavior.