Influence of grain size on orientation changes during plastic deformation

Polycrystalline copper, nickel and iron with grain sizes of 100 μm, 10 μm, 1 μm and about 100 nm were deformed in an in situ deformation stage installed in a scanning electron microscope to study the influence of grain size on orientation changes during plastic deformation. By using the electron back scatter diffraction technique, the microstructural evolution and the crystallographic orientation rotation behaviour taking place during tensile deformation were investigated at three different deformation steps. On the basis of the captured data, domains near grain boundaries show different orientation changes as compared to the inner region of a grain, especially in samples with grains larger than 10 μm. At grain sizes smaller than 1 μm, this distinctive difference between the near grain boundary region and the interior of grains disappears. In summary, it could be shown that orientation changes in grains larger than 1 μm differ significantly from the behaviour in submicrometer and nanocrystalline materials.