Crystal plasticity-based micromechanical finite element modelling of ductile void growth for an aluminium alloy under multiaxial loading conditions

This work proposes a crystal plasticity-based micromechanical finite element model to account for the inelastic crystallographic slip in an aluminium alloy and its effect on the development of micro-voids. Three-dimensional unit cell with periodic boundary conditions is used to represent the porous single crystal, which is subject to multiaxial external loads with constant stress triaxiality. The effects of stress triaxiality and crystallographic orientation on the ductile failure response for the porous single crystal are then quantified. Through the Taylor–Reuss mean field homogenisation, the stress–strain responses for porous polycrystal under multiaxial stress states are also investigated and compared with the conventional modelling results. The present work indicates that void coalescence strain at single crystal level strongly depends on the crystallographic orientation, particularly when stress triaxiality is low, and the overall stress–strain response of porous polycrystal can be affected by the crystallographic slip-based micro-void growth and polycrystallinity of the material.