TEXTURAL AND STRUCTURAL REGULARITIES OF DEFORMATION BY ROLLING OF Zr-2.5%Nb ALLOY

A review of studies of regularities of changes in the crystallographic texture of the longitudinal and cross rolling of the Zr-2.5%Nb alloy is given. Accordingly with this, plates were made from longitudinal fragments and rings of a tube 15.01.5 mm from the fuel assemblies of Russian RBMK reactors. The plates were annealed at 580 °C for 3 h. X-ray studies of texture changes with the degree of deformation of the plates by rolling were carried out. The principle of method of inverse pole figures was used with the calculation of the Kearns texture coefficients, as well as measurements of tilt curves (0002) was. Non-uniformiity of deformation during straightening of the tube blanks was taken into account. It is found that the main rotations of crystallographic c-axes in the plates at any rolling direction are carried out in the plane corresponding to the cross-section of the original tube. Existence of an initial stage of increased textural changes during deformation of the plates is found, what is qualitatively and quantitatively related to activity of tensile twins of the {1012}[1011] system. Regularities in texture changes at the subsequent moderate stage of deformation with the participation of compression twins are considered. The purely twinning nature of the textural doublet, which latter is characteristic of the rolling texture of metals of the titanium subgroup, is explained. It is noted and explained a fact that during cross rolling of plates (made from tube rings), textural changes occur at a rate twice as high as during longitudinal rolling. As considered, all similar regularities can be carried out for the metals of the titanium subgroup.