Texture Changes in the Plastic Deformation Zone Near the Fracture Surface of the Zr-1% Nb Alloy Sheet

Abstract
A wave of local plastic deformation moves in front of any crack and is responsible for strain hardening and rotation of crystalline lattice within the layer adjacent to the fracture surface. It was found by X-ray diffractometric study, that a directional reorientation of grains takes place near the fracture surface, leads to formation of the specific cristallographic textures and controls the further movement of the crack. The fracture anisotropy of the rolled zirconium alloy correlates with the character of observed texture changes in the plastic deformation zone and can be predicted using the texture formation models by taking into account a variety of α-Zr deformation micromechanisms. Alternative activation of prismatic slip or twinning depending on the tension direction determines both the thickness and the structure features of the plastic deformation zone near the fracture surface.