Effects of plasticity on the crack propagation resistance of a metal/ceramic interface

Abstract

Fracture experiments have been conducted on a gold/sapphire interface. The interface is found to fail by interface separation in a nominally “brittle” manner with a critical strain energy release rate, G c ≈ 50 Jm −2, substantially larger than the work of adhesion, W ad ≈ 0.5 Jm −2. Evidence of plastic deformation on the gold fracture surface, such as blunting steps and slip steps, suggest that plastic dissipation is the primary contribution to the measured G c . Calculations suggest that the majority effect occurs in the plastic zone through the crack wake. The interface is also found to be susceptible to slow crack growth.