Analysis of Slip Transfer Across Grain Boundaries in Ti Via Diffraction Contrast Tomography and High-Resolution Digital Image Correlation: when the Geometrical Criteria Are Not Sufficient

High-resolution digital image correlation was employed to analyze the occurrence of slip transfer across grain boundaries in pure Ti. The microstructure was characterized in 3D through diffraction contrast tomography and electron backscatter diffraction. The prismatic slip activity was captured in the shear strain maps at different strains, and the grain boundaries were classified according to the occurrence/absence of slip transfer. Different geometrical slip transfer criteria were tested, and, in general, the slip transfer likelihood increased when the slip systems across the boundary were well-aligned. Nevertheless, a detailed analysis of selected grain boundaries revealed that slip transfer could be triggered or impeded depending on the local stresses acting on the neighborhood, regardless of the alignment between the slip systems. The microstructural and deformation patterns where the geometrical criteria are not enough to predict slip transfer are assessed.