Orientation image-based micromechanical modelling of subgrain texture evolution in polycrystalline copper

An efficient full-field formulation based on fast Fourier transforms (FFTs) for the prediction of the viscoplastic deformation of polycrystals is applied to the study of the subgrain texture and microstructure evolution in polycrystalline Cu deformed under tension. Direct input from orientation imaging microscopy (OIM) images is used in the construction of the initial unit cell. Average orientations and misorientations predicted after 11% tensile strain are directly compared with OIM measurements, showing good agreement. The differences between misorientations of surface grains compared with bulk grains are estimated, and the orientation dependence of intragranular misorientations is studied. Measurements and simulations agree in that grains with initial orientation near 〈1 1 0〉 tend to develop higher misorientations. This behavior can be explained in terms of attraction towards the two stable orientations and grain interaction. Only models that account explicitly for interaction between individual grains, like the FFT-based formulation, are able to capture these effects.