FRACTURE AND CRACK PROPAGATION OF METALLIC BILAYERS USING QUASI-CONTINUUM SIMULATIONS

Abstract

The effects of the constituting material, initial crack length, and crystal orientation on the fracture and mechanics of bilayers with an interface crack under tension are studied using quasi-continuum simulations in terms of atomic trajectories, strain distribution, the stress-strain curve, and the crack growth-strain curve. The simulation results show that at the initial tension stage, the bilayers exhibit linear elasticity regardless of initial crack length and constituting material. With an increase in initial crack length at a layer interface, the yield stress, yield strain, and ultimate stress of the bilayers decrease. Bilayers with along er initial crack under tension have faster crack growth. Bilayers with a structural orientation of [020] versus [101̅] have lower mechanical strength compared to that of those with structural orientations of [100] versus [010] and [1̅10] versus [010]. The Ni/Ni bilayer has the highest yield stress and ultimate stress under tension.