Accurate determination of active slip systems using a novel lattice rotation analysis: Quasi-in-situ EBSD/ECCI study on the homogeneous/ heterogeneous deformation of polycrystalline zirconium

The accurate determination of slip systems is crucial for understanding deformation mechanisms of metals in particular, how slip/twining transfer or blocking occurs. This paper proposes a novel crystallographic lattice rotation analysis, which combines quasi-in-situ Electron Back Scatter Diffraction (EBSD) and Electron channeling contrast imaging (ECCI) techniques to precisely predict the active slip system with specific slip directions in polycrystalline Zr. Large data sets for hundreds of grains were quantitatively analyzed by this method to statistically gain deep insight on the deformation mechanism of Zr. Our results show that prismatic (a) slip is the primary slip system in most grains, and pyramidal (a) slip plays a secondary role in coordinating the local stress state of plastic deformation. The predicted slip direction is the same as the direction in which dislocation density increases. This method can serve as a complementary tool to the intragranular misorientation axis (IGMA) method, bridging the gap between macro-mechanical response and microstructural deformation mechanisms.