Evolution of grain-scale microstructure during large strain simple compression of polycrystalline aluminium

Polycrystalline deformation and its modeling by currently used crystal plasticity models has been investigated by means of an experiment involving direct measurement of deformation induced orientation changes. The experiment used a quasi-columnar grained Aluminum (Al) sample, whose lattice orientations were mapped using the Orientation Imaging Microscopy (OIM) technique. The sample was then compressed by 40% (along the axis of the columnar grains) and was found that most of the grains had significant in-grain misorientations in the form of deformation bands with two morphologies - either elongated on the grain scale or nearly equiaxed. The deformation was then simulated using the classical Taylor-type model. A comparison of the predictions with the experimental results showed that the Taylor-type model captured well the tendency to move towards a <110> fiber texture but failed to predict correctly which <110> pole rotated, and also by its implicit assumptions could not predict any in-grain misorientation.