A CPFEM based 3D Model for Polycrystalline Plasticity with Diffused Grain Boundaries

Understanding the relationship between the microstructure of polycrystalline materials and their macroscopic properties is critical for developing and improving them for advanced applications. In polycrystalline aggregates, the combination of computational homogenization and crystal plasticity has shown promise in simulating the effective properties and capturing such correlations. Our study uses a similar framework to model polycrystals with FCC and BCC crystal structures. The goal is to investigate the plastic deformation behavior of these materials, specifically focusing on the role of Geometrically Necessary Dislocations (GNDs). We employ a phenomenological Crystal Plasticity (CP) model on a cubic Representative Volume Element (RVE). The simulations capture the effect of crystallographic orientations, grain boundaries, and dislocation mechanisms on the deformation of polycrystalline RVE. To account for the complex behavior at grain boundaries, a diffused interface model is proposed. This model homogenizes the deformation behavior within the grain boundary region to capture more effectively the hardening due to dislocation pile-up, providing a more realistic representation of the interaction between grains. Our findings provide insights into the influence of grain boundaries on the overall strain hardening and deformation response of polycrystalline materials.