A STUDY OF RESIDUAL-STRESSES IN ZIRCALOY-2 WITH ROD TEXTURE

The development of high grain-to-grain interactions in Zircaloy-2 poly crystals is due to the anisotropy of the thermal, elastic and plastic properties of the constituent grains. These residual stresses modify t he mechanical performance of the material, as well as its response und er neutron irradiation. Here we simulate the evolution of internal str esses in Zircaloy-2 with rod texture, when the aggregate is cooled dow n from the annealing temperature, and also when it is subjected to ten sile and compressive deformation. We implement for that purpose an ela sto-plastic self-consistent scheme that accounts for grain interaction s, and compare our predictions with experimental determinations of res idual strains obtained by neutron diffraction. Our results are in good quantitative agreement with the experimental evidence, and represent a qualitative improvement over the predictions of the more rigid upper -bound approach. We discuss the role that slip and twinning systems pl ay in the macroscopic response of the aggregate and in the evolution o f internal stresses.