The role of crystallographic orientations on heterogeneous deformation in a zirconium alloy: A combined experimental and modeling study

Abstract

This study explores the effect of crystallographic orientations on the development of residual strains and local misorientations in a polycrystalline Zircaloy-4 during controlled tensile deformation. A combination of experiments (electron backscattered diffraction (EBSD), micro-Laue diffraction) and modeling (crystal plasticity finite element (CPFE)) are used. Data from two sets of grain orientations are analyzed and modeled: orientations within 5° of the exact (0002) basal pole (‘near basal’) and those within 5° of the exact (101‾0) prism pole (‘near prism’). In order to maintain similitude with experiments, the actual experimental microstructures (along with their crystallographic orientations) are used as an input for the CPFE simulations. Minor differences are observed for different measures of local misorientation developments. However, the ‘near basal’ grains show higher spread of grain reference orientation deviation, both in experiments and in CPFE simulations, and correlate with the intergranular strain heterogeneity predicted from CPFE simulations. Simulated trends of residual strains also compare favorably with the micro-Laue measurements. The ‘near basal’ grains have higher residual strains as compared to the ‘near prism’ grains. This observed behavior appears to originate from the elastic anisotropy of the hcp crystals and not from differences in the plastic deformation on the different family of slip systems.