Cohesive zone representation of interfacial fracture in aluminum-silicon bimaterials

Interfacial fracture in three aluminum-silicon bimaterials with different crystal orientations under tensile loading was investigated by molecular dynamics simulations. Interface crack propagates in a brittle manner regardless of crystal orientation. The overall distribution of normal stress and separation along the interface is consistent with conventional continuum fracture mechanics. Normal traction-separation curves were extracted from simulation results and compared with three cohesive zone models. Crystal orientation shows negligible effect on the trend of normal traction-separation curves. From the perspective of the trend of the normal traction-separation curves, the exponential cohesive zone model exhibits the closest match with simulation results. When it comes to fracture toughness, the bilinear cohesive zone model has the best agreement with simulation results.