Comparison of R-curves from single-edge V-notched-beam (SEVNB) and surface-crack-in-flexure (SCF) fracture-toughness test methods on multilayered alumina-zirconia composites

The single-edge V-notched-beam fracture testing method was used to measure the short-crack R-curve behavior of a 90-vol%-alumina-10-vol%-ceria-doped z irconia multilayered composite. The initiation and extension of short crack s from the V-notch tip were observed in situ via optical microscopy. Initia l crack lengths of 15-50 mu m were obtained repeatedly. The resulting R-cur ve was similar to the R-curve that was measured using the surface-crack-in- flexure testing method. The ability to control the position of the V-notch tip within a material permits study of the influence of specific microscopi c features on the fracture behavior.