A slip-gradient-based dislocation density crystal plasticity model for predicting GND evolution and grain-scale plastic deformation in a tantalum oligocrystal

This work presents crystal plasticity finite element (CPFEM) simulations to investigate the grain-scale plastic deformation in an oligocrystalline tantalum specimen subjected to different strain levels, using initial crystallographic orientations derived from electron backscatter diffraction (EBSD) data. A dislocation density-based constitutive model considering the contributions of statistically stored dislocations (SSDs) and geometrically necessary dislocations (GNDs) is employed to describe the evolution of slip resistance during the deformation. The predicted stress–strain response shows reasonable agreement with literature-reported data. The simulations reveal pronounced accumulation of GNDs at grain boundaries, with density decreasing towards grain interiors and increasing systematically with strain. The influence of initial crystallographic orientation on deformation heterogeneity and texture evolution is also investigated and compared with reported data.