A methodology to study crystal plasticity inside a compression test sample based on image correlation and EBSD

Modified compression tests in a coarse-grained austenitic stainless steel have been carried out in order to examine the crystal plasticity behavior for large plastic deformations. The measurements of local in-plane strains provide deeper insight into the deformation process on the local scale. These measurements are performed by digital image correlation technique (DIC) in combination with local crystal orientation measurements by using the electron backscatter diffraction technique (EBSD). Split test samples are prepared to track the strong microstructural changes during deformation, which is done incrementally in 10% steps up to 60% total macroscopic strain. The clear correlation of local strains with crystal orientation changes – e.g. in the case of mechanical twinning – permits to identify the acting deformation mechanisms. Such, experimentally determined local strain maps can be used for verification of crystal plasticity finite element method simulations (CPFEM).

Research Highlights
► Method to study large strain crystal plasticity inside an austenitic FeCrNi-alloy.
► Correlation of local strain analyses with crystal orientation measurements.
► Deformation mechanism changes locally from dislocation glide to mechanical twinning.
► Suitable to study grain–grain interactions, slip system activation and grain boundary effects.
► Provide essential data for crystal plasticity FEM studies.