Toughening of layered ceramic composites with residual surface compression: effects of layer thickness

摘要

Shielding of edge cracks in multilayer single-edge-notch-bend (SENB) specimens, with alternating layers designed to produce residual compression and balancing tension, was calculated by the method of weight function. Investigation of the effects of the relative thickness of the layers and of the number of layers revealed that the maximum crack shielding and the maximum apparent fracture toughness were achieved in three-layer composites with the thickness of the compression layer constituting one-half ot the specimen height with an edge crack extending to the first interface. These theoretical predictions were confirmed with measurements of apparent fracture toughness in the range. 28-32 Mpa√m, on three-layer SENB specimens of alumina-zirconia composites.