A multiscale phenomenological constitutive model for strain rate dependent tensile ductility in nanocrystalline metals

•A variational multiscale constitutive model that accounts for strain rate dependent ductility during intergranular failure in nanocrystalline fcc metals.•Model’s ability to predict the damage and fracture has been depicted through experimental validations.

A variational multiscale constitutive model that accounts for strain rate dependent ductility of nanocrystalline materials during intergranular failure has been presented. The presented model is an extension of the previous work [1], in which a nanocrystalline material is modelled as two-phase with grain interior being modelled using crystal plasticity theory while grain boundary affected zone using porous plasticity model which accounts for ductile damage due to void growth and coalescence. The model capability of capturing the strain rate dependent deformation and failure has been demonstrated through validations against uniaxial test data taken from literature. The validated results show a good agreement between experimental and simulated response.