Influence of material anisotropy on void coalescence by necking for face-centered cubic single crystals

Abstract

This paper presents the coalescence of microvoids embedded in an anisotropic copper single crystal using a micromechanics approach. Crystal plasticity framework was used to account for the anisotropy arising from the orientation and slip. A full 3D representative volume element (RVE) with void was considered to circumvent spurious loading. The constant load path parameters were enforced on the RVE using multi-point constraints. Various loading conditions that lead to necking were studied. The key finding from the present study is the interplay of the load path parameters (triaxiality and Lode parameter), material anisotropy, and initial void volume fraction on the void coalescence. It is noticed that at high triaxiality, the ductile failure mechanism is dominated by the necking mechanism, and at medium to low triaxiality, the ductile failure mode is a combination of shearing and necking mechanisms. It was observed that non-homogenous crystallographic slip manifests the material anisotropic effects in void cell RVE across various crystallographic orientations. The crystal orientation [110] exhibited higher shearing than the orientation [100] and [111]. Further, material anisotropy significantly affected void morphology but not the void coalescence strains at high triaxial values.