Fatigue deformation mechanism of the annealed Zircaloy-4 with texture

Polycrystalline metals with a HCP structure such as Zircaloy-4 show a unique deformation behavior and fracture characteristics under cyclic loading conditions. As the HCP materials have limited slip systems and a tendency to develop a preferred orientation (texture) and twins, they show deformation anisotropy resulting from the texture during plastic deformation. It is widely known that the fully annealed metals usually show cyclic hardening. However, the fully annealed Zircaloy-4 alloy showed cyclic softening under the total strain range less than 1.6%, which was explained by texture-rotation induced cyclic softening model in previous paper. This paper is showing the experimental evidences supported the model in terms of dislocation behavior during fatigue