Crack behavior at bi-crystal interfaces: A mixed atomistic and continuum approach A. R. Pillai and R. E. Miller Materials Research Society Symposium Proceedings, 653, Z2.9.1-Z2.9.7 (2001). ABSTRACT Interfacial defects like grain boundaries and phase boundaries play an important role in the mechanical behaviour of engineering alloys. In this work the problem of a crack on a bi-crystal interface is studied at the at\omic scale, with the goal of elucidating the effects of varying interatomic interaction on crack behaviour and to assess the suitability of existing fracture criteria to the anisotropic bi-crystal case. Calculations are performed using the Quasicontinuum (QC) method. Using suitable approximations, some of the existing fracture criteria were used to predict ductile or brittle fracture and compared to the QC results.