Investigation of texture and dislocation density in rolled β-brass by X-ray and neutron diffraction

Abstract

In order to calculate the dislocation density from the broadening of diffraction profiles following the theory of Krivoglaz [1,2] and Wilkens [3] it is necessary to know the mean orientation factor χ which depend on the individual slip system, the type and Burgers vector b of the dislocations, the diffraction vector g and the elastic moduli C ij. Because of the deformation of β-brass several slip systems were proposed to appear at different temperatures [4] the idea realized in the present work was to roll β-brass at room temperature (RT) and 300 °C to different strains, to measure the texture and to compare it with simulated textures using the different slip systems. It could be shown that the (211)[11] slip system is preferred especially at higher deformation degrees and also at elevated temperatures. Simulation by using only non-[111] Burgers vectors does not fit the experimental textures at all. If only the (110)[11] slip system is activated the ideal orientation 001〈10〉 decreases with increasing strain which equals the behaviour at low strains at RT and is contrary to that at 300 °C. Accordingly, the dislocation densities were determined by assuming only [111] superdislocations of screw character. The dislocation densities determined with the diffraction vector in normal direction of the rolling plane do not fit the Taylor equation with a fixed constant a of the dislocation interaction which is in agreement to the observed increase of the sphere of the strain field of a single dislocation.