Investigation of Near Grain Boundary Gradient Zones Using HRDIC and HREBSD

It is well known that deformation behavior in polycrystalline materials is modified significantly in the region of grain boundaries (GBs), in comparison to the response at the center of grains. This study observes various aspects of deformation response in FCC nickel and BCC tantalum using high-resolution digital image correlation (HRDIC) and high-resolution electron backscatter diffraction (HREBSD). Contrasting behavior is observed in terms of slip band nucleation and propagation, modification to active slip systems near GBs, strain and orientation gradients and geometrically necessary dislocation (GND) distributions, and transmission across GBs. Correlations between local microstructural features and deformation response in the near-boundary gradient zones are analyzed. The insights are used to assess the performance of crystal plasticity type models and inform the next generation of simulation approaches.