Slip transfer across grain boundaries was studied in annealed polycrystalline Al foils deformed in uniaxial tension by means of the analysis of the slip traces on the specimen surface. Grain orientations and selected grain boundary misorientations were measured on both surfaces of the sample using electron back-scattered diffraction mapping. It was found that most of the grains were within 15° of a cube orientation and approximately half of the grains percolated through the specimen thickness. The Luster-Morris " parameter (that can be computed from the surface grain orientation) was used to assess the likelihood of slip transfer across boundaries. It was found that transfer across grain boundaries was rare in near-cube oriented grains, and convincing evidence was only found when " > 0.97, which corresponds to lowangle boundaries with <15º misorientation. This behavior was explained by the presence of many active slip slips in near-cube oriented grains that favor self-accommodation of the grain shape to the evolving boundary conditions imposed by neighboring grains instead of promoting slip transfer across the boundary. These results indicate that the alignment between slip planes and slip directions across the boundary is not the only important metric to determine the threshold for slip transfer, as the particular details of deformation in each grain (such as the number of available slip systems) also must be considered.

The slip transfer phenomenon was studied at the grain boundaries of pure Aluminum by means of slip trace analysis. Either slip transfer or blocked slip was analyzed in more than 250 grain boundaries and the likelihood of slip transfer between two slip systems across the boundary was assessed. The experimental results indicate that slip transfer was very likely to occur if the residual Burgers vector, ∆b, was below 0.35b and the Luster-Morris parameter was higher than 0.9, and that the ratio of the Luster-Morris parameter and the residual Burgers vector has a threshold above which slip transfer is probable.

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