Micromechanical modeling of the elastic-viscoplastic deformation for considering voids and imperfect interfaces in sintered nano-silver under compression

The effects of voids and imperfect interfaces are key issues in the constitutive modeling of porous materials. In the current study, uniaxial compression experiments of short column specimens are performed to investigate the stress–strain relation of porous sintered nano-silver at different temperatures and loading rates. A micromechanical-based constitutive model is proposed to describe the mechanical behaviors of elastic-viscoplastic deformed polycrystalline materials with voids and imperfect interfaces. In the developed model, crystals with different orientations and voids are assumed to be embedded in the homogeneous equivalent medium (HEM). The behavior of single crystal is determined by a crystal plasticity model. A modified self-consistent model is proposed to describe the overall response of HEM by calculating the algorithmic tangent operator and affine strain increment of void and single crystals. The accuracy and rationality of the proposed model is validated by comparing the calculated results with a 3D crystal plasticity finite element (CPFE) model. Influences of the imperfect interface parameter and voids volume fraction on elastic and elastic-viscoplastic deformed media are investigated. The maximum allowable volume fraction of the void is analyzed. The model is applied to simulate the experimental data. The result shows that the proposed model can describe the elastic-viscoplastic deformation of sintered nano-silver with reasonable accuracy.