In-situ observation of bulk 3D grain evolution during plastic deformation in polycrystalline Cu

•Non-destructive measurement of volumetric microstructure evolution is demonstrated.•Bulk grain evolution with strain is examined in ∼5000 3D tracked grains.•Orientation gradients are strongly correlated with grain size.•Lattice reorientation suggests substantial influence of local neighborhood.•3D evolution data is invaluable for input/validation of crystal plasticity models. We present a non-destructive in-situ measurement of three-dimensional (3D) microstructure evolution of 99.995% pure polycrystalline copper during tensile loading using synchrotron radiation. Spatially resolved three-dimensional crystallographic orientation fields are reconstructed from the measured diffraction data obtained from a near-field high-energy X-ray diffraction microscopy (nf-HEDM), and the evolution of about 5000 3D bulk grains is tracked through multiple stages of deformation. Spatially resolved observation of macroscopic texture change, anisotropic deformation development, and the correspondence of different crystallographic parameters to defect accumulation are illustrated. Moreover, correlations between different crystallographic parameters, such as crystal rotation evolution, short- and long-range orientation gradient development, microstructural features, and grain size effects are investigated. The current state of data mining tools available to analyze large and complicated diffraction data is presented and challenges associated with extracting meaningful information from these datasets are discussed.