Homogenization scheme for brittle intergranular decohesion in polycrystalline aggregates

•Grain boundary decohesion is included in a new transition rule for polycrystals.•Homogenized behaviour of a copper alloy under intergranular cracking is predicted.•A single tensile fracture test can be used to identify grain boundary parameters.

The overall fracture behaviour of polycrystalline aggregates is strongly conditioned by intergranular failure, as is the case in copper alloys subjected to dynamic embrittlement. The self-consistent scheme is extended to account for grain boundary decohesion using a nonlinear cohesive law. The effective tensile response up to failure is computed for a Cu–Ni–Si alloy based on the homogenization method. In particular, the proposed approach allows for identification of the grain boundary critical energy release rate from the macroscopic tensile curve.