Modeling lattice strain evolution during uniaxial deformation of textured Zircaloy-2

An elastoplastic self-consistent model was used to interpret the experimental lattice strain evolution previously reported for testing in three directions of a thick polycrystalline Zircaloy-2 slab. The model was used to infer the underlying deformation mechanisms. The influences of prism 〈a〉 slip, basal 〈a〉 slip, pyramidal 〈c + a〉 slip and tensile twinning were considered. The critical resolved shear stresses and hardening parameters for each mode were obtained by simultaneously fitting the macroscopic flow curves, Lankford coefficients and internal elastic strain development for all diffraction peaks, for the combination of three measurement directions and three loading directions, for compression and tension. The effects of dislocation interactions during deformation and hardening between deformation modes were considered. Tensile twinning inferred from the intensity changes of the diffraction peaks and its activity was qualitatively reproduced by the simulations for compression in the plate rolling and transverse directions and tension in the plate normal direction.