Texture Evolution During Compression in Zircaloy-2

Abstract

The deformation of Zircaloy-2 is influenced by many factors; one being bulk texture. The texture can greatly affect the development of both the macro-mechanical (e.g. stress-strain curve) and micro-mechanical behavior (e.g. intergranular stresses). Thus studies on texture evolution are of practical significance. This introduces our current work on texture development during uniaxial loading of warm rolled Zircaloy-2 slab. As manufactured, most basal poles are orientated along the normal direction (ND), with a spread of ±50° towards the transverse direction (TD) and ±30° towards the rolling direction (RD). The { 0211 } normals are moderately concentrated in RD. Compression tests were performed in-situ during neutron diffraction to follow the development of lattice strain and intensity for eight diffraction peaks, with two tests each for compression along ND, TD and RD. Pole figures were then measured for the deformed samples. In this paper, we report the results for compression along RD. The development of intensity measured in two perpendicular directions during compression along RD showed that tensile twinning occurred during the deformation, which was confirmed by the subsequent texture measurement. Modeling work was performed with a visco-plastic self-consistent model (VPSC), assuming that prism slip, basal slip, pyramidal slip and tensile twinning are the active deformation mechanisms. The model successfully reproduced the macroscopic stress-strain responses, and also predicted the final texture reasonably well. Although further work is needed to refine the results, the model predicts reasonably well tensile twinning activity, and the twinning-induced reorientation of basal poles from ND to RD, and prism poles from RD to ND.