Dislocation structure in different texture components determined by neutron diffraction line profile analysis in a highly textured Zircaloy-2 rolled plate

Abstract

A novel diffraction-based method has been developed to determine the substructure in terms of the fraction of prevailing slip systems and dislocation densities in multiple individual texture components of strongly textured materials. The method was applied to a strongly textured cold-rolled Zircaloy-2 sample, compressed along the normal direction of the rolled plate. Fourteen diffraction patterns were collected by time-of-flight neutron diffraction experiments at seven different purposely selected sample orientations. The diffraction peaks corresponding only to one single texture component out of the four prevailing components were identified and used to construct texture-specific diffraction patterns. The best five such patterns were evaluated by the convolutional multiple whole profile procedure of line profile analysis for the fractions of the prevailing 〈a〉-, 〈c + a〉- and 〈c〉-type slip systems and the corresponding dislocation densities. It is found that in the three texture components with thecaxis not parallel to the normal direction of rolling the average dislocation densities and fractions of slip-system types are the same. However, in the texture component with thecaxis parallel to the normal direction of rolling the fraction of the 〈a〉-type slip system is somewhat smaller than in the other components and that of the 〈c〉-type slip system is somewhat larger than zero. The fractions of the prevailing slip systems are in good correlation with literature data of self-consistent polycrystal plasticity modeling of Zircaloy-2.