Bicrystals with symmetrical <112> tilt boundaries and misorientations of 8.7° (low-angle), 15.4° (transition) and 31.5° (high-angle) were deformed in a channel die in order to study the effect of misorientation upon deformation at grain boundaries. The samples were characterized by strain measurements and micro-texture mapping. The experimental results were compared with finite-element crystal plasticity simulations. Strain heterogeneity was studied at the macroscopic and microscopic levels. Even macroscopically homogeneous areas exhibited microscopic heterogeneity in the form of bands of different sets of glide systems. Clear effects of grain-boundary misorientation upon the deformation kinematics close to the boundaries were observed. The 8.7° grain boundary did not exhibit any orientation change which could be interpreted in terms of free dislocation penetration. The 15.4° and 31.5° bicrystals exhibited orientation changes which were attributed to dislocation pile-ups.

On the Influence of the Grain Boundary Misorientation on the Plastic Deformation of Aluminum Bicrystals. S.Zaefferer, J.C.Kuo, Z.Zhao, M.Winning, D.Raabe: Acta Materialia, 2003, 51[16], 4719-35