STIFFNESS OF GRAIN-BRIDGING ELEMENTS IN A MONOLITHIC ALUMINA

The postfracture tensile (PFT) technique isolates the crack wake to ch aracterize the mechanical behavior of the grain-bridging elements as a function of crack-opening displacement, Incorporating the PFT stiffne sses into a Hooke's law-based model provides insight to the nature of the active bridging mechanism, The conventional model, which presumes to extract prismatic grains from sockets in the mating fracture face, is not consistent with the low wake stiffnesses presented here, In con junction with fractographic evidence, such low wake stiffnesses sugges t the strong influence from other, more compliant, mechanisms such as grain rotation, asperity loading, and ligament bending.