Anisotropic yielding behavior and associated mechanism of cold rolled and annealed Zircaloy-4 alloy thin sheets under tensile condition

Abstract

The significant yielding anisotropy of cold rolled and annealed Zircaloy-4 (Zr-4) alloy thin sheets was investigated by performing uniaxial tensile tests along the two typical directions, the rolling direction (RD) and transverse direction (TD). The associated deformation mechanism was determined by the combined analysis of critical resolved shear stress (CRSS) and calculated Schmid Factor (SF) value that dependent on crystallographic texture. Prismatic <a> slip was demonstrated to be the dominant deformation mechanism for the material yielding. Results revealed that the specific crystallographic orientation of the Zr-4 alloy caused by rolling texture, influences the activities of prismatic <a> slip by affecting their SF, which was depending on the geometric relationship between loading direction and crystallography, thereby leading to the anisotropic deformation. Quantitative analysis of this dominant deformation mode showed that the variety of prismatic <a> slip activity with the loading direction gave rise to the yielding anisotropy of Zr-4 alloy sheets under tensile condition.