FRACTURE-RESISTANCE CHARACTERISTICS OF A METAL-TOUGHENED CERAMIC

The fracture characteristics of an Al2O3/Al composite are examined. Measurements of resistance curves and work of rupture are compared with predictions of a micromechanical model, incorporating the effects of crack bridging by the Al reinforcements. The bridging traction law is assumed to follow linear softening behavior, characterized by a peak stress, sigma(c), and a critical stretch-to-failure, u(c). The values of simga(c) and u(c) inferred from such comparisons are found to be broadly consistent with independent measurements of stretch-to-failure, along with the measured flow characteristics of the Al reinforcement. The importance of large-scale bridging on the fracture resistance behavior of this class of composite is also demonstrated through both the experiments and the simulations.