Published online by Cambridge University Press: 28 February 2011
Current understanding of R-curve behaviour and the strength-toughness relationship of transformation-toughened ZrO2-containing ceramics is reviewed. If the toughness increases with crack, extension along an R-curve, a maximum in strength versus toughness is observed, which is related to the crack instability criterion for R-curves. An analytical expression from a well-known “wake” theory of crack tip shielding due to McMeeking and Evans is used to compute R-curves and strength/toughness relations, which are compared with experiment.