Development of internal strains in textured Zircaloy-2 during uni-axial deformation

Internal strains can greatly affect the mechanical performance of Zircaloy-2 and the study of their development provides insight into the operating deformation mechanisms. In this study, neutron diffraction was used to track the development of internal strains in three dimensions in samples cut from a rolled Zircaloy-2 slab. The samples were subjected to room temperature compression or tension in situ in the neutron diffractometer with loading along each of the three principal directions of the slab. The recorded intensity changes for the different crystallographic planes also provided information on the grain reorientations during deformation. Strong evidence was found for tensile twinning in tensile tests in the plate normal direction and in compression tests in the transverse and rolling directions. This provides an extensive data set with which to develop and test models for plastic deformation and texture development in polycrystalline Zircaloy-2.