Development of texture inhomogeneity in sheets from Zr-based alloys under high-temperature rolling

Abstract

Deformation processes under hot rolling of sheets from Zr-based alloys for chemical and nuclear industries are considered by data of the layer-by-layer X-ray texture analysis. An essential texture inhomogeneity of studied sheets testifies, that the deformation conditions in successive layers prove to be rather various depending on the distance of layer from the surface and promote operation of different mechanisms of plastic deformation, including crystallographic slip in the low-temperature -phase with HCP crystalline lattice and in the high-temperature -phase with BCC crystalline lattice as well as noncrystallographic mutual shifts of grains by their boundaries. The latter is conditioned by development of dynamic recrystallization or phase transformations, observed by texture features of corresponding layers. The real temperature of concrete layers deviates from the nominal one within ( + )-region of Zr-Nb phase diagram due to the heat sink to rolls and local heating by deformation. Changes in reductions per pass and in the total number of passes allow to weaken the texture component, produced by rolling in -phase and unfavorable for mechanical properties of the sheet.