Fracture and damage at interfaces of ceramic laminates

Interfacial fracture properties of three different layered ceramics, silicon nitride and boron nitride composite, zirconia and alumina composite, coarse and fine grained alumina composite, are investigated using Hertzian contact and indentation tests. Different to the weak interfaces required to enhance the long crack toughness of layered ceramics, STRONG layer interfaces are preferred for the current layered composites in order to suppress crack growth by using the elastic mismatch, residual stresses or special interface microstructures. Experimental results of indentation tests and Hertzian contact tests performed with the bonded-interface technique are discussed with respect to individual layer structure design.