Understanding void growth at grain boundaries

Void growth and coalescence during spall failure in shock-loaded materials are dependent on the microstructure and deformation of the material surrounding their nucleation sites. To understand the growth of voids under deformation, scientists have turned to 3D micromechanics modeling to ascertain the combined effects of microstructure and voids on mechanical properties. It is often observed that voids grow preferentially in certain regions of the microstructure, such as in certain grains and at grain boundaries. Yet, the role of these features on void growth is not well understood. In this presentation, we will use a large strain elastic-viscoplastic crystal plasticity model implementation in an FFT-based solver (LS-EVPFFT) to simulate void growth in relation to its surrounding material. The calculations are designed to elucidate the roles of crystallography, grain boundary inclination, and grain boundary misorientation on void growth at grain boundaries. In simulation, we consider an FCC metal as a model material but the approach can apply to metals of other crystal structures. The growth of these GB voids, focusing on both total growth and growth into each individual grain, are compared to the growth of intragranular voids in single crystals.